WITHIN ROTATING MEMBERS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. provisional application Serial No. 62/622,411 filed January 26, 2018, and entitled“Rotating Control Devices and Methods to Detect Pressure Within Rotating Members,” which is hereby incorporated herein by reference in its entirety for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

BACKGROUND

[0003] Field of the Disclosure

[0004] The present disclosure relates generally to drilling systems and to rotating control devices for such systems. More particularly, the disclosure relates to systems and methods for monitoring annular seals between concentric fluid conduits as they rotate relative to each other.

[0005] Background to the Disclosure

[0006] In applications requiring the transmission of fluid under relatively high pressure, it is sometimes necessary to interconnect a rotatable conduit with a stationary conduit, and to provide annular seals therebetween to prevent leakage of the pressurized fluid. One such application is in drilling operations where a drill pipe or another tubular member passes through a rotating control device (RCD), where the outer housing of the RCD remains stationary while an internal sleeve and annular seals surround and rotate along with the drill pipe. The annular seals allow the drill pipe to move axially into or out from a wellbore without fluid leakage. When it is thought that a seal failure has occurred -whether actual or perceived- drilling operations are halted so that the seals can be inspected and possibly replaced. However, drilling costs are very high, such that downtime must be avoided or minimized as much as possible. Consequently, systems and apparatus that can definitively indicate that a seal failure is imminent or has occurred would be welcomed by the industry.

p l BRIEF SUMMARY OF THE DISCLOSURE

[0007] These and other needs in the art are addressed in one embodiment by a rotating control device (RCD) for a well comprising: a housing having a through-bore extending along a central axis, a housing wall, and a sensor disposed at a sensor position in the housing and extending into the housing wall. The RCD includes a sleeve comprising a sleeve bore aligned with the central axis and configured to rotate about the central axis, within the through-bore of the housing, as well as a pressure-responsive assembly coupled to the sleeve and configured to generate a response to a pressure of fluid within the sleeve bore. The pressure-responsive assembly is coupled to the sleeve at a location such that it passes the sensor position periodically as the sleeve rotates within the through-bore. The sensor is configured to detect the response of the pressure-responsive assembly.

[0008] In some embodiments, the pressure-responsive assembly includes a pressure- responsive element in fluid communication with the sleeve bore; and the pressure-responsive element is configured to be free of sliding engagement with the sleeve when responding to a change in pressure in the sleeve bore.

[0009] In some embodiments, the pressure-responsive assembly comprises a first piston slidingly disposed inside a piston cartridge and configured to move from a first position to a second position relative to the piston cartridge in response to an activation pressure in the fluid within the sleeve; wherein the sensor is configured to detect the presence of the first piston when the first piston is in the second position and passes the sensor position; and wherein the piston is separated from the sleeve by the piston cartridge.

[0010] The sleeve may further include an outer surface, and a first piston port extending from the sleeve outer surface, with the first piston port being in fluid communication with the sleeve bore. In some embodiments, the pressure-responsive assembly is disposed in the first piston port with the first piston in fluid communication with the sleeve bore; wherein the first piston is configured to slide without contacting the first piston port.

[0011] In some embodiments, the rotating control device further comprises a burst disc coupled to the piston cartridge and disposed to seal the first piston from the fluid within the sleeve until the fluid reaches or exceeds a prescribed pressure.

[0012] In some embodiments, the rotating control device further comprises a plurality of pressure-responsive assemblies, each pressure-responsive assembly coupled to the sleeve at a different location such that it passes the sensor position periodically as the sleeve rotates within the through-bore; wherein each pressure-responsive assembly is configured to generate a response to a particular pressure of the fluid within the sleeve bore; and the sensor is configured to detect the responses of each of the plurality of pressure-responsive assemblies.

[0013] In some embodiments, the pressure-responsive assembly comprises a transducer configured to emit a first wireless signal including pressure data corresponding to the pressure of the fluid within the sleeve; wherein the sensor comprises a receiver and transmitter device configured to receive the pressure data from the transducer when the transducer is within a detection range of the sensor, and wherein the receiver and transmitter device is configured to transmit the pressure data beyond the housing.

[0014] Also disclosed is an RCD including: a housing comprising a first bore extending along a central axis, and a sensor port extending to the first bore, the sensor port disposed at a discrete circumferential location about the central axis; a sensor disposed within the sensor port; a rotating sleeve assembly (RSA) extending at least partially within the first bore. The RSA includes: a rotating sleeve configured to rotate about the central axis relative to the housing and comprising a sleeve outer surface, a second bore coaxially aligned with the first bore, and a first piston port extending from the sleeve outer surface to the second bore; and a first piston disposed within the first piston port and configured to reciprocate between a first position and a second position in response to a change in pressure of fluid within the second bore. The first piston port and the first piston are disposed at a location in the rotating sleeve that passes the sensor periodically when the rotating sleeve rotates relative to the housing; and the sensor is configured to detect the first piston when the first piston rotates past the sensor and is in its second position.

[0015] In some embodiments, the rotating sleeve further comprises a plurality of piston ports, and the RSA comprises a plurality of pistons, each piston being disposed within one of the plurality of piston ports and configured to reciprocate between a first position and a second position in response to a change in pressure of a fluid within the second bore; wherein each piston of the plurality of pistons is biased towards its first position and each piston port and each piston are disposed at a location in the rotating sleeve that passes the sensor during each rotation when the rotating sleeve rotates relative to the housing. The sensor is configured to detect each piston when the piston rotates past the sensor and the piston is in its second position; and wherein each piston includes a sensing portion that is in fluid communication with the second bore, each sensing portion having a wettable face area that differs from the wettable face area of another of the plurality of pistons.

[0016] In some embodiments, the RSA further comprises a rotational speed indicator coupled to the rotating sleeve at a location that passes the sensor during each rotation when the rotating sleeve rotates relative to the housing; and wherein the sensor is configured to detect the rotational speed indicator when the rotational speed indicator rotates past the sensor.

[0017] In some embodiments, the plurality of piston ports, the plurality of pistons, the sensor port, the sensor, and the rotational speed indicator are all aligned parallel to a plane that extends perpendicular to the central axis.

[0018] In some embodiments, the RSA further comprises a burst disc disposed to seal the first piston port at a location between the second bore and the first piston.

[0019] In some embodiments, the RSA further includes a piston assembly comprising: a piston cartridge disposed at a fixed location within the first piston port; and the piston slidingly disposed in the piston cartridge; wherein the piston is separated from the sleeve by the piston cartridge. The first piston may be configured to be free from sliding engagement with the first piston port. The sensor may be one configured to detect the first piston by a phenomenon selected from a group consisting of: proximity, magnetic field, Hall Effect, contact, induction, capacitive interaction, and photoelectric interaction.

[0020] Also disclosed is an RCD comprising: a housing having a through-bore extending along a central axis and a sensor positioned at a first axial position; a sleeve configured to rotate within the through-bore of the housing; and a piston coupled to the sleeve and configured to move from a first position to a second position in response to a pressure change of a fluid within the sleeve, the piston being coupled to the sleeve at a location such that it passes by the first axial position periodically when the sleeve rotates within the through-bore. The first piston is configured to be free from sliding engagement with the sleeve, and the sensor is configured to detect the piston when the piston is in the second position. In some embodiments, the sensor is positioned at a discrete circumferential location about the central axis, and in some embodiments, the RCD includes a piston assembly comprising: a piston cartridge disposed at a fixed location in the sleeve, wherein the piston is slidingly disposed in the piston cartridge and the piston is separated from the sleeve by the piston cartridge.

[0021] In some embodiments, the RCD incudes: a plurality of piston assemblies, each piston assembly comprising: a piston cartridge disposed at a fixed location in the sleeve and including a fluid communication bore, a location that passes by the first axial position periodically when the sleeve rotates; and a piston slidingly disposed in the piston cartridge and separated from the sleeve by the piston cartridge, the piston including a piston neck slidingly and sealingly received within the fluid communication bore, the piston configured to move from a first position to a second position in response to a pressure change of a fluid within the sleeve; wherein each piston neck of the plurality of piston assemblies has a different wettable face area than another of the piston necks.

[0022] In some embodiments, the RCD further comprises a rotational speed indicator coupled to the rotating sleeve at a location that passes the sensor during each rotation of the sleeve relative to the housing; wherein the sensor is configured to detect the rotational speed indicator when the rotational speed indicator rotates past the sensor.

[0023] A method for operating a rotating control device is disclosed and includes: providing a housing having a through-bore, a housing wall, and a sensor disposed at a sensor position in the housing; disposing a sleeve within the through-bore of the housing, the sleeve configured to rotate about the central axis of the housing and comprising a sleeve bore aligned with that axis; coupling a pressure-responsive assembly that includes a pressure-responsive element to the sleeve at a location such that the pressure-responsive assembly passes the sensor position periodically as the sleeve rotates within the through-bore, and such that the pressure- responsive element is in fluid communication with the sleeve bore. The method further incudes: disposing a tubular string sealingly within the sleeve bore; rotating the tubular string and the sleeve with respect to the housing; and, using the sensor, detecting a response of the pressure-responsive assembly when pressure in the sleeve bore reaches an activation pressure; performing a system action when the sensor detects a response of the pressure- responsive assembly. The detecting may include measuring periodically the pressure in the sleeve bore. Further, where the detectable member is coupled for movement with a piston disposed in a cartridge, the detecting may include detecting radial movement of the pressure- responsive element relative to the cartridge and the sleeve.

[0024] Thus, embodiments described herein include a combination of features and characteristics intended to address various shortcomings associated with certain prior devices, systems, and methods. The various features and characteristics described above, as well as others, will be readily apparent to those of ordinary skill in the art upon reading the following detailed description, and by referring to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a detailed description of the disclosed exemplary embodiments, reference will now be made to the accompanying drawings:

[0026] Figure 1 shows cross-sectional side view of an embodiment of a rotating control device having a pressure-responsive assembly mounted in a rotating sleeve in accordance with principles described herein;

[0027] Figure 2 shows an enlarged, cross-sectional side view of the rotating control device of Figure 1;

[0028] Figure 3 shows cross-sectional top view of the rotating sleeve of the rotating control device of Figure 2;

[0029] Figure 4 shows a cross-sectional side view of the pressure-responsive assembly of

Figure 2;

[0030] Figures 5A and 5B show perspective views of a cap covering the external end of the pressure-responsive assembly in Figure 2;

[0031] Figure 6 shows an enlarged cross-sectional side view of the rotating control device of Figure 1 with the pressure-responsive assembly in a deactivated state;

[0032] Figure 7 shows an enlarged cross-sectional side view of the rotating control device of Figure 1 with the pressure-responsive assembly in an activated state;

[0033] Figure 8 shows another embodiment of a pressure-responsive assembly in accordance with principles described herein;

[0034] Figure 9 shows another embodiment of a rotating control device having a pressure- responsive assembly mounted in a rotating sleeve in accordance with principles described herein; and

[0035] Figure 10 is a flow diagram showing a method for operating a rotating control device configured for use in an oil well system in accordance with principles described herein.

NOTATION AND NOMENCLATURE

[0036] The following description is exemplary of certain embodiments of the disclosure. One of ordinary skill in the art will understand that the following description has broad application, and the discussion of any embodiment is meant to be exemplary of that embodiment, and is not intended to suggest in any way that the scope of the disclosure, including the claims, is limited to that embodiment.

[0037] The figures are not drawn to-scale. Certain features and components disclosed herein may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness. In some of the figures, in order to improve clarity and conciseness, one or more components or aspects of a component may be omitted or may not have reference numerals identifying the features or components. In addition, within the specification, including the drawings, like or identical reference numerals may be used to identify common or similar elements.

[0038] As used herein, including in the claims, the terms“including” and“comprising,” as well as derivations of these, are used in an open-ended fashion, and thus are to be interpreted to mean“including, but not limited to... ” Also, the term“couple” or“couples” means either an indirect or direct connection. Thus, if a first component couples or is coupled to a second component, the connection between the components may be through a direct engagement of the two components, or through an indirect connection that is accomplished via other intermediate components, devices and/or connections. The recitation“based on” means“based at least in part on.” Therefore, if X is based on Y, then X may be based on Y and on any number of other factors. The word“or” is used in an inclusive manner. For example,“A or B” means any of the following:“A” alone,“B” alone, or both“A” and“B.” [0039] In addition, the terms“axial” and“axially” generally mean along or parallel to a given axis, while the terms“radial” and“radially” generally mean perpendicular to the axis. For instance, an axial distance refers to a distance measured along or parallel to a given axis, and a radial distance means a distance measured perpendicular to the axis. Furthermore, any reference to a relative direction or relative position is made for purpose of clarity, with examples including “top,” “bottom,” “up,” “upper,” “upward,” “down,” “lower,” “clockwise,”“left,”“leftward,”“right,” and“right-hand.” For example, a relative direction or a relative position of an object or feature may pertain to the orientation as shown in a figure or as described. If the object or feature were viewed from another orientation or were implemented in another orientation, it may then be helpful to describe the direction or position using an alternate term. DETAILED DESCRIPTION OF THE DISCLOSED EXEMPLARY EMBODIMENTS

[0040] The present disclosure involves monitoring potential fluid leakage between a rotatable conduit and a stationary conduit that are interconnected. Leakage between the rotatable conduit and the stationary conduit is inhibited by seals that may rotate with the rotatable conduit or may remain stationary with the stationary conduit, but eventually, a seal may fail, allowing leakage. Gathering information so as to know when a seal fails or predict failure can be challenging. Commonly, fluid leakage is avoided by preventative maintenance. Various embodiments disclosed herein provide indication of fluid leakage past a seal. These embodiments include a pressure-responsive element or assembly, for example a pressure sensor or a movable piston, coupled to a rotating member and arranged in fluid communication with a zone where leakage may occur.

[0041] Referring to Figure 1, in an exemplary embodiment, a well system 90 includes equipment for various well operations 92, including a rotating control device (RCD) 100, governed by a control system 94. RCD 100 extends along a central axis 101 and is configured to receive sealingly a tubular member, which in this example is a pipe 102, which may be part of a string of tubular members. Device 100 is suitable as a member of a wellhead over a borehole of a well, such as a hydrocarbon well. Device 100 includes an outer housing 110 holding a sensor 120 and includes a rotating sleeve assembly (RSA) 125 received within housing 110. RSA 125 holds a pressure-responsive assembly within housing 110, generally aligned with sensor 120 along axis 101. In this embodiment, the pressure- responsive assembly is a piston assembly 200. Sensor 120 is configured to detect the presence of the assembly 200 as a result of one or more pressure conditions that may exist in sleeve assembly 125 as sleeve assembly 125 or pipe 102 causes assembly 200 to rotate relative to housing 110 and sensor 120.

[0042] Housing 110 includes a housing wall or tubular body 111 extending along the central axis 101 from a lower end 112 to an upper end 113, having an outer surface and a through- bore 114. Through-bore 114 is centered on axis 101 and defines an inner wall. Housing 110 also includes a sensor port 116 extending along a central axis 117 through tubular body 111 to the through-bore 114. Housing 110 also includes a plurality of fluid ports 118 also extending radially through tubular body 111 to the through-bore 114, and being axially spaced from port 116. Sensor 120 is disposed in sensor port 116, extending toward the through-bore 114. The axial position of port 116 and sensor 120 may be measured from any convenient location such as a surface at the housing’s upper end 113 or a surface at its lower end 112. The location of port 116 in housing 110 defines a sensor position for sensor 120. The sensor position may be further defined by the depth of sensor 120 within port 116 or the proximity of the inner end of sensor 120 to the surface of through-bore 114. Port 116 and sensor 120 are positioned at a discrete axial location along central axis 101 and at a discrete circumferential location about axis 101.

[0043] Rotating sleeve assembly RSA 125 extends at least partially within the through-bore 114 of housing 110. RSA 125 includes a rotatable sleeve 130 received within a bearing assembly 180 to rotate about axis 101 relative to the housing 110, a speed indicator 131 received in sleeve 130 at a location along axis 101 that is aligned with sensor 120 of outer housing 110, and piston assembly 200 received in sleeve 130 at the same location along axis 101 as speed indicator 131. Consequently, assembly 200 is also axially aligned with sensor 120 so it can be detected by sensor 120. Sleeve 130 and pipe 102, when installed, are configured as rotatable conduit, and housing 110 is configured as a stationary conduit.

[0044] Sensor 120 is configured to detect the presence of speed indicator 131 and to detect the presence of piston assembly 200 by any known technology, capability, or phenomenon, which may be selected from the sensor group consisting of: proximity, magnetic field, Hall Effect, contact, reed, induction, capacitive interaction, and photoelectric interaction, as examples. In Figure 1, speed indicator 131 and piston assembly 200 each include a magnet, and sensor 120 includes Hall Effect sensor; although, various other embodiments include another type of speed indicator 131, piston assembly 200, or another type of sensor 120.

[0045] Rotating sleeve 130 includes a sleeve outer surface 134 and a bore 136 extending from a lower end 132 to an upper end 133. In Figure 1, rotating sleeve 130 is formed from an upper sleeve member 140 coupled to a lower sleeve member 160 by a sleeve coupling 165. Referring to both Figure 1 and Figure 2, a collar 168 is coupled to sleeve member 140 at upper end 133, and an upper packing element 170A extends downward from the bottom of collar 168, into member 140. Collar 168 is generally tubular, being open at both ends to receive pipe 102 therethrough. A lower packing element 170B extends downward from sleeve member 160 at lower end 132. Packing elements 170A,B are configured to seal around the circumference of pipe 102, isolating the bore 136 from an upper portion of collar 168 and from upper and lower portions of bore 114 in housing 110, to prevent fluid leakage from these regions. The seal of packing elements 170A,B is maintained even as sleeve 130 and pipe 102 rotate relative to housing 110 during operation. In at least some modes of operation, rotation of pipe 102 causes sleeve 130 to rotate due to the gripping action of elements 170A,B. Collar 168, packing elements 170A,B, and bore 136 provide a sealable through-passage for a tubular member, e.g. pipe 102, to extend or pass through housing 110, which in some arrangements leads into a borehole. Bore 136 is configured to be an isolated chamber when a tubular member is installed.

[0046] Upper sleeve member 140 extends from a threaded lower end 142, which attaches to sleeve coupling 165, to upper end 133, which attaches to collar 168. Sleeve member 140 includes a radially protruding annular shoulder 146 located between ends 142, 133, a port 148 extending into shoulder 146 along a central axis 149 coplanar with central axis 117 of port 116, and a piston port 152 extending into shoulder 146 along the same axis 149 but opposite port 148. Some misalignment between axis 149 and 117 is acceptable in various embodiments depending on the sensitivity of sensor 120. Port 148 is configured to receive speed indicator 131 at a fixed position along port axis 149, disposing speed indicator 131 at a fixed distance from axis 101, being generally flush or adjacent to outer surface 134. Whenever sleeve 130 rotates the indicator 131 to the circumferential position of sensor 120, the magnet of indicator 131 is at a fixed distance from sensor 120 within its detection range (e.g. a prescribed distance). Repeated movement of speed indicator 131 past sensor 120 provides a measurement of the rotational speed of sleeve 430 with respect to housing 110. Thus, sensor 120 is configured as a speed sensor.

[0047] A shown in Figure 3, in the current embodiment, shoulder 146 of sleeve member 140 includes a plurality of ports 152 aligned on a common plane with port 148. Each port 152 extends from outer surface 134 to the bore 136 and includes first, second, and third portions each having a different diameter and resulting in a first shoulder 154A and a second shoulder 154B, both facing radially outward. Shoulder 154A is proximal bore 136 and distal outer surface 134 of sleeve 130, while shoulder 154B is proximal outer surface 134. Each port 152 is configured to receive a piston assembly 200 at a selected or fixed location. In Figure 3, piston assembly 200 threaded within port 152 and is disposed against shoulder 154A. Thus, the current embodiment of rotating sleeve 130 includes a plurality of piston assemblies 200. In Figure 3, rotating sleeve 130 includes three piston ports 152 and three piston assemblies 200. As stated above, one of the piston ports 152 is aligned along the same central axis 149 as port 148. The other two ports 152 are aligned and extend along a second central axis 149 coplanar with and perpendicular to the first axis 149. Piston assemblies 200 in ports 152 and speed indicator 131 in port 148 are aligned parallel to the cross-sectional plane shown in Figure 3, which extends perpendicular to the central axis 101 of device 100. Some embodiments have other orientations for a port 152 or the multiple ports 152.

[0048] Referring again to Figure 1, bearing assembly 180 includes a bearing housing 182 that is coupled within housing 110 to remain stationary, a bearing sleeve 184 coupled to sleeve 130 to grasp and rotate with sleeve 130, and bearing 186 coupled between housing 182 and sleeve 186. In this example, bearing 186 includes two opposing sets of tapered roller bearings to resist axial thrust in either vertical direction from, for example, pipe 102.

[0049] In Figure 1, control system 94 is coupled to sensor 120 of RCD 100 by a communication conductor or cable 192. Control system 94 of well system 95 governs the well operations 92 and monitors responses from sensor includes RCD 100. For example, during operation, as speed indicator 131 periodically passes sensor 120, control system 90 determines the rotational speed of sleeve 130 with pipe 102. If a leak occurs through one of the seals 170A, 170B, and the fluid pressure in bore 136 rises to an activation pressure (described below) for one of the piston assemblies 200, the corresponding piston 250 and magnet 284 will move radially outward to a second position. Sensor 120 will detect this response, and control system 94 will perform a system action, causing a change to a well operation 92, such as activating an indicator 194, storing process data electronically, reducing the flow of drilling mud, reducing drilling speed, or another action. Indicator 194 may produce an audible or visual warning and may be a stand-alone device or may be incorporated into a graphical user interface, as examples. In some instances, when the pressure in bore 136 rises further, another piston assembly 200 (e.g. Figure 3) experiences an activation pressure, causing the corresponding piston 250 and magnet 284 to move radially outward to a second position. Sensor 120 will detect this additional response and may perform another system action, such as modifying the performance of indicator 194 or performing one of the other system actions describe above.

[0050] Referring now to Figure 4, piston assembly 200 extends along a central axis 201 from a first end 202 to a second end 203 and includes a piston 250 slidingly received within piston cartridge 210 and held by a piston nut 230. Piston cartridge 210 includes a cylindrical body 212 that includes a threaded region 214 on its outer surface proximal but spaced apart from end 203, a fluid communication bore 216, a counter bore 218 extending from bore 216, a threaded counter bore 219 extending from bore 218 to end 203, and an annular face seal 222 p. l l at end 202 to engage shoulder 154A of port 152 (Figure 3). In Figure 3, piston cartridge 210 is threaded within port 152 of rotatable sleeve 130 and is disposed at a fixed location against shoulder 154A. Referring again to Figure 4, the base of bore 218 forms a shoulder 220 facing end 203 where bore 218 intersects with bore 216. The base of bore 219 forms a shoulder 221 facing end 203 where bore 219 intersects with bore 218. Bores 216, 218, 219 are concentric about axis 201. Piston nut 230 is received within cartridge 210 and includes a base 232 configured to couple threadingly to counter bore 219, a neck 234 extending from base 232 distal or opposite end 203, a through-bore 236 extending axially through base 232 and neck 234, and a tool socket 238 formed in through-bore 236 proximal at end 203. Base 232 is configured to couple threadingly to counter bore 219 and butt against shoulder 221. In this configuration, bore 219 includes straight threads, but in some embodiments bore 219 includes another type of thread, such as tapered pipe threads.

[0051] Piston 250 extends along central axis 201 from a first end 252 to a second end 253. Piston 250 includes a base portion 254 extending from second end 253, a shoulder portion 256 extending from base portion 254, a piston neck 258 extending from shoulder portion 256, and a counter bore 272 extending into the outer end of base portion 254 at second end 253, opposite neck 258. Base portion 254, shoulder portion 256, and neck 258 are each round and concentric about axis 201. Shoulder portion 256 has a larger diameter than base portion 254 and neck 258. Assembled as shown, neck 258 is slidingly received within bore 216, shoulder portion 256 slidingly received within bore 218, and base portion 254 extends from bore 216 to bore 218. A clearance is provided between circumference of shoulder portion 256 and bore 218 to allow a fluid, such as air, that is trapped in cartridge 210 to move axially from side to side of portion 256 as piston 250 reciprocates during operation. An annular seal 274 is disposed about the circumference of neck 258. A resilient member, which in this embodiment is a spring 280, is received about piston base portion 254 and about neck 234 of nut 230. Spring is held between the nut’s base 232 and piston shoulder portion 256. The outer end of piston 250 includes a detectable portion or member, which in this example is a magnet 284. Magnet 284 is threadingly received into the piston’s counter bore 272 and includes a shouldered end 288 that is located outside and beyond piston 250, toward end 203. The combined length of piston 250 and magnet 284 is shorter than the length of cartridge 210.

[0052] Referring again to Figure 3, the three piston assemblies 200 are threaded into piston ports 152, and a threaded cartridge cap 290 is installed within the outer end of each port 152 adjacent shoulder 154B. Each piston assembly 200 is configured to be assembled and then installed as a single unit into a port 152. Caps 290 prevent or discourage liquids, slurries, or contaminants in bore 114 from contacting piston assembly 200. Cap 290 provides piston assembly 200 with pressure compensation with respect to a fluid in through-bore 114 of housing 110. The fluid may be, for example, located above device 100. Cap 290 is configured to isolate or insulate piston assembly 200 from the pressure or presence of that fluid. Figure 5A and Figure 5B provide an outside and an inside view of a cap 290. In some embodiments, cap 290 includes a material that is non-magnetic, a polymer, or a non-metal.

[0053] Figure 6 and Figure 4 show a resting or deactivated state for a piston assembly 200. Figure 6 shows a close-view of the assembly 200 installed in sleeve 130 of device 100. Piston assembly is assembled such that spring 280 is partially compressed between piston nut 230 and piston shoulder portion 256, which presses shoulder portion 256 radially inward toward cartridge shoulder 220. Piston neck 258 is in fluid communication with bore 136 and performs as a sensing portion of piston 250, making piston 250 a pressure-responsive element. Seal 274 on neck 258 prevents fluid communication between bore 136 and the other portions 254, 256 of piston 250. As a result, the exposed or wettable face area of neck 258, which is proximal the end 202, governs the response of piston 250 to fluid pressure in bore 136. The exposed or wettable face area is the net surface area at end 252 of piston 250 that is configured to be in fluid communication with port 152 or bore 136 and is perpendicular to axis 149. Thus, in some embodiments, in which piston end 252 is no perpendicular to axis 149, whether end 252 be flat or curved, the exposed or wettable face area is a calculable area that projected to be perpendicular to axis 149. On piston 250, the arrangement of neck 258 and seal 274 to engage piston cartridge 210 and not to engage port 152, configures piston assembly 200 to respond to pressure independently of any diameter of port 152. In addition, the inclusion of neck 258 and seal 274 configures piston assembly 200 to respond to pressure independently of the dimensions of structural portions of piston 250 (e.g. portions 254, 256), structural portions that, for example, provided the mounting of piston 250 within a housing bore (e.g. bore 218 of cartridge 210 or port 152) or interact with spring 280.

[0054] Referring still to Figure 6, any fluid in bore 136 is at a pressure Pl that is too low to exert sufficient force against piston neck 258 to overcome the force of spring 280, and thus piston 250 remains unmoved. The piston’s shoulder portion 256 is axially spaced apart from neck 234 on nut 230. Piston neck 258 is adjacent, and in this embodiment, is flush with end

202. Piston magnet 284 is displaced axially inward from end 203 of piston cartridge 210 or nut 230 and is displaced axially inward from outer surflace 134 of sleeve 130. In this state, piston 250 and, consequently, magnet 284 are disposed at a resting or deactivated position with respect to housing 210 or sleeve 130, evaluated along the aligned axes 149, 201. With magnet 284 in a deactivated position, the radial distance 295A between magnet 284 and sensor 120 is greater than the detection range of sensor 120 when piston axis 201 is aligned with or adjacent the sensor port axis 117, as is the case in Figure 6. Therefore, sensor 120 ignores magnet 284 when sleeve 130 rotates relative to housing 110.

[0055] Figure 7 shows another close-view of the same piston assembly 200 within sleeve 130, showing an activated state for piston assembly 200. In response to a prescribed pressure of the fluid in bore 136, spring 280 is compressed. The fluid pressure P2 within bore 136 in Figure 7 is greater than pressure Pl of Figure 6. Pressure P2 is equal to or greater than a prescribed threshold pressure value and may be called an“activation pressure” for the piston assembly 200. In general, the activation pressure or a range of activation pressures to which assembly 200 responds is be predetermined by the configuration of assembly 200. In Figure 7, the increased pressure has acted against the end face of piston neck 258, causing piston 250 and magnet 284 to move to radially outward, to an activated position with respect to piston housing 210 or sleeve 130, evaluated along the axes 149, 201. When the fluid pressure within sleeve 130 rises to the value P2, assembly 200 responds by piston 250 moving from a deactivated position to an activated position. In the activated position, magnet 284 is closer to end 203 of piston cartridge 210 or nut 230 and is closer to outer surface 134 of sleeve 130. Shoulder portion 256 of piston 250 contacts neck 234 on nut 230, which acts as a“stop,” limiting the leftward movement of piston 250. When magnet 284 is in its activated position, and when piston axis 201 is aligned with or is adjacent the sensor port axis 177, as is the case in Figure 7, then the radial distance 295B between magnet 284 and sensor 120 is within the detection range of sensor 120. Therefore, during operation, sensor 120 will produce a signal in response to its proximity to magnet 284, each time magnet 284 rotates past sensor 120. Piston 250 remains in the activated position as long as the pressure in bore 136 remains above the prescribed pressure of the piston assembly. Spring 280 biases piston 250 toward the innermost deactivated position and causes piston to move to this or to an intermediate deactivated position when pressure in bore 136 drops below the prescribed pressure. Thus, piston 250 and magnet 284 are configured to reciprocate within cartridge 210 between a deactivated position and an activated position in response to fluid pressure within bore 136 of sleeve 130. For example, the fluid pressure may rise from rising from a value of Pl to a value of P2 and cause the piston to move. Piston assembly 200 is configured such that piston 250, including seal 274, does not engage slidingly the piston port 152 when responding to a change in pressure in the sleeve bore 136. Piston 250 is separated from sleeve 130 by piston cartridge 210. In the embodiment of Figure 6 and Figure 7, piston 250 does not contact piston port 152 in any position of piston 250.

[0056] The movement of piston 250 between a deactivated position and an activated position is based on the wettable face area of piston neck 258, the“spring constant” of spring 280, any preloading on spring 280, the pressure inside bore 136, and, in some embodiments, the pressure in the through-bore 114 of housing 110 at piston port 152. In some embodiments or some instances, an intermediate activation pressure that is greater than pressure Pl but less than pressure P2 moves magnet 284 an intermediate position that is within the detection range of sensor 120 without piston 250 moving fully to its radially outermost position, not sufficiently displaced to contact neck 234 on nut 230. This type of intermediate position qualifies as another activated. Similarly, it is possible for piston 250 to be disposed away from the innermost deactivated position that is shown in Figure 6 and still have magnet 284 outside detection range of sensor 120 when piston axis 201 is adjacent or aligned with port axis 117. Any such intermediate position of piston 250 relative to sleeve 130 may also be called a deactivated position, wherein magnet 284 is undetectable by sensor 120.

[0057] In at least some embodiments, sensor 120 is selected to produce an output signal having a strength or a value that varies based on the distance between sensor 120 and piston 250, e.g. magnet 284, when piston axis 201 is adjacent or aligned with port axis 117 and magnet 284 is in one of a plurality of activated positions. Sensor 120 may be an inductive- type proximity sensor, for example. When piston 250 is moved along axis 201 to an intermediate activated position within the detection range of sensor 120 (as explained above), the strength or value of the signal produced by sensor 120 may be less than a maximum strength or value that occurs when piston 250 is in its outermost activated position. In some embodiments, this variation in the output signal of sensor 120 is correlated to pressure values, configuring control device 100 to provide pressure indication or measurement over a range of pressure values rather than just a binary“yes/no” comparison between pressure inside sleeve 130 and a single prescribed pressure value.

[0058] Referring again to Figure 3, the three piston assemblies 200 are additionally labeled with the reference numerals 200A,B,C to distinguish the different diameters and wettable face areas of the necks 258 of each corresponding piston 250A,B,C. Each piston 250A,B,C is shown in its innermost, deactivated position unmoved by the pressure of a fluid that may be in bore 136 when device is unused or is operating. Piston 250A has a neck with the largest diameter of the three pistons, piston 250B has a neck with a smaller diameter, and piston 250C has a neck with a still smaller diameter. In this embodiment, each spring 280 has the same spring constant, a property that correlates the force that will be exerted by a spring to the distance the spring is compressed or stretched, having the units of force per unit length of displacement. The force that a fluid in bore 136 exerts on any of the pistons is proportional to the wettable face area of the piston’s neck 258. Each piston 250A,B,C “sees” or experiences the same fluid pressure from bore 136. However, that fluid pressure exerts a larger force on piston 250A than on either of the other two pistons because the neck 258 of piston 250A has the largest wettable face area exposed to the fluid in bore 136. Similarly, the fluid force exerted on piston 250B is larger than the fluid force exerted on piston 250C, which has the smallest wettable face area exposed to the fluid. Thus, during operation of device 100 (Figure 1), piston 250A will be moved out of a deactivated position and to an activated position by a lower pressure than is required to move piston 250B or piston 250C. Likewise, piston 250B will be moved out of a deactivated position by a lower pressure than is required to move piston 250C.

[0059] Referring to Figure 1 and Figure 3, an operating condition will be considered in which piston assemblies 200A,B,C become sequentially activated and detected by sensor 120. Four pressures will be discussed, wherein a pressure Pl < a pressure P2 < a pressure P3 < a pressure P4. With packing elements 170A,B initially sealed around pipe 102, each piston 250A,B,C is in a deactivated position and is not activated by pressure Pl that exists in bore 136 of sleeve 130. Pipe 102 and sleeve 130, along with packing elements 170A,B, are rotating. Initially, sensor 120 senses only speed indicator 131, which it senses once per revolution. In this example, as the pipe 102 rotates, packing element 170B wears, and fluid, which may be drilling mud for example, begins to leak from the lower portion of through- bore 114 in housing 110, past packing elements 170B, and into bore 136 of sleeve 130. As fluid enters sleeve 130, bore 136 reaches an activation pressure P2 that is able to push piston 250A, which is the piston with the largest neck 258, to an activated position (e.g. Figure 7). Sensor 120 now senses both speed indicator 131 and the magnet 284 on piston 250A as each of these elements periodically move past sensor 120 while sleeve 130 rotates. In at least one embodiment, sensor 120 cannot distinguish between speed indicator 131 and a magnet 284, rather the operator or control system 94 (Figure 1) detects a distinct increase in the detection rate of sensor 120 (e.g., twice as many pulses per second) and attributes this change to piston assembly 200A being activated by a pressure P2 or greater but less that pressure P3. Thus, based on the characteristics of sensor 120 and the arrangements of position indicator 131 and piston assemblies 200 relative to sensor 120, sensor 120 is configured to detect data for two separate operational conditions, the first condition being rotational speed and the second condition being elevated pressure within rotatable sleeve 130. In some embodiments, the rotational speed of the pipe is also measured elsewhere in the well operation system, such as in a top drive or in a kelly table, and the data from sensor 120 is compared against this other measurement of rotational speed to assess whether sensor 120 is detecting speed indicator 131 alone or it is also detecting a magnet 284 in a piston assembly 200. Thus, a real change in rotational speed can be differentiated from a pressure rise within sleeve 130 when evaluating the data of sensor 120.

[0060] As the scenario continues, the pressure of fluid in bore 136 increases to an activation pressure P3 that that is able to push piston 250B to an activated position (e.g. Figure 7). Piston 250A remains in its activated position. Sensor 120 now senses speed indicator 131 and two magnets 284 as these three move past sensor 120 in sequence while sleeve 130 rotates. Again, the operator or the control system 94 interprets the additional data from sensor 120 as resulting from pressure P3 or greater being detected in bore 136, the pressure being less than P4. As fluid continues to push past packing element 170B into bore 136, the pressure in bore 136 increases to an activation pressure P4 that that is able to push piston 250C, which is the piston with the smallest neck 258, to an activated position (e.g. Figure 7). Pistons 250A,B remains in their activated positions. Sensor 120 now senses speed indicator 131 and three magnets 284 while sleeve 130 rotates. The operator or the control system 94 interprets the additional data from sensor 120 as resulting from a pressure P4 or greater being detected in bore 136.

[0061] Referring to Figure 8, another embodiment of a pressure-responsive assembly consistent with the present disclosure and configured for installation in rotating control device (RCD) 100 is a piston assembly 300. An assembly 300 may replace a piston assembly 200 in various embodiments of RCD 100 and sleeve 130. Assembly 300 is shown installed in a piston port 152 of a rotating sleeve 130 with port 152 extending along a central axis 149 from a sleeve outer surface 134 and to bore 136, which extends about a central axis 101. Sleeve 130 includes the features disclosed above, including the figures. Assembly 300 is configured to be assembled into a single, cohesive unit before being installed into port 152.

[0062] Assembly 300 is similar to piston assembly 200 in that assembly 300 includes a piston 350 held within piston cartridge 310 by a piston nut 330. However, piston assembly 300 also includes an end cap 360 that is configured to isolate piston 350 from a fluid in bore 136 until a prescribed pressure is reached in bore 136. Assembly 300 extends along a central axis 301 from a first end 302 to a second end 303. Piston cartridge 310 includes a cylindrical body 312 includes an internally threaded first bore 316 extending from end 302 and a counter bore 218 extending from end 303 to bore 316. The base of bore 218 forms a shoulder 220 facing end 203 where bore 218 intersects with bore 216. Cartridge 310 is threadingly received in port 152 of rotatable sleeve 130 and is disposed at a fixed location against shoulder 154A. Piston nut 330 is externally threaded and includes a through-bore 236 for piston 350 and a tool socket 238 formed concentric or within bore 236. Nut 330 lacks a neck like neck 234 on nut 220 (Figure 4). However, even some embodiments of nut 220 lack a neck 234.

[0063] Piston 350 extends along central axis 201 from a first end 352 to a second end 353. Piston 350 includes a base portion 354 extending from second end 353, a shoulder portion 356 extending from portion 354 to the outer surface of first end 352, and a counter bore 272 within portion 354 at second end 353. Shoulder portion 356 has a larger diameter than base portion 354 and includes a groove to receive a seal 374. A resilient member, a spring 280, is received about piston base portion 254 and is held between nut 330 and piston shoulder portion 356. The outer end of piston 350 includes a detectable portion or member, which in this example is a magnet 284 threadingly received into the piston’s counter bore 272. Spring 280 biases piston 350 and therefore magnet 284 away from assembly end 303 and toward a deactivated position of piston 350 and magnet 284 in cartridge 310, which is the position shown in Figure 8. Some embodiments include a cartridge cap (Figure 5B) installed in the outer end of piston port 152, adjacent surface 134. In some embodiments, nut 330 exerts a preloading compression to spring 280 while piston 350 is in its resting position.

[0064] End cap 360 includes a bore 361 extending along axis 201 from a first end 362 to a second end 363 and includes an outwardly extending annular flange 364, and a burst or rupture disc 366. Disc 366 sealingly covers bore 361 at first end 362. Flange 364 has a face seal 222 that engages shoulder 154A of port 152 proximal bore 136 and distal the outer surface 134 of sleeve 130. The cap’s second end 363 is threadingly received within bore 316 of cartridge 310 and flange 364. Rupture disc 366 is in fluid communication with sleeve bore 136 and is configured to break when it experiences a prescribed pressure differential that may be caused by a fluid within sleeve bore 136 reaching or exceeding an activation or threshold pressure, as discussed above. Rupture disc 366 is an example of a pressure-responsive element that is configured not to engage slidingly the piston port 152 when responding to a change in pressure in the sleeve bore 136.

[0065] As assembled, shoulder portion 356 at piston end 353 is pressed against cartridge shoulder 220 or cap 360 when piston 350 is disposed at a deactivated position as shown in Figure 8. Piston 350, which is a pressure-responsive element, and at least a portion of the outer surface of shoulder portion 356 will be in fluid communication with port 152 and bore 136 if rupture disc 366 breaks. Shoulder portion 356 is a sensing portion of piston 350. If rupture disc 366 breaks due to an activation pressure, piston 350 and magnet 284 will move outward to a second location, and this second location will be within the sensing range of sensor 120 when assembly 300 is rotationally aligned with sensor 120. Piston 350 will return to a deactivated position under the influence of spring 280 when the pressure subsides. Piston assembly 300 is configured such that piston 230, including seal 374, does not engage slidingly the piston port 152 when installed in sleeve 130 and responding to a change in pressure in the sleeve bore 136. Piston 350 is separated from sleeve 130 by piston cartridge 310. In the embodiment of Figure 8, piston 350 does not contact piston port 152 in any position of piston 350.

[0066] Piston assembly 300 is configured to operate like assembly 200 except for the addition of rupture disc 366, which governs at least an initial the response of piston 350 to a change in pressure within bore 136. This differs from assembly 200 in which the wetted area of neck 258 governs the response of piston 250. To configure assembly 300 to respond to a higher or lower pressure within bore 136, a rupture disc 366 having an appropriate pressure rating is selected and installed. The pressure rating of disc 366 can be varied while maintaining a constant, selected diameter for disc 366 and while maintaining a constant, selected diameter for port 152 into which disc 366 is installed. Thus, inclusion of disc 366 configures piston assembly 300 to respond to an activation pressure independently of any diameter of port 152. The inclusion of disc 366, which initially isolates piston 350 from fluid in bore 136, configures piston assembly 300 to respond to an activation pressure independently of piston 350. Thus, this response of piston assembly 300 to pressure within sleeve 130 is independent of the dimensions of structural portions of piston 350 (e.g. the diameter of a portion 354, 356), structural portions that, for example, provide the mounting of piston 350 within a housing bore (e.g. bore 218 of cartridge 310) or that interact with spring 280.

[0067] To use multiple piston assemblies 300 in the configuration of Figure 3 and to have each assembly respond do a different pressure or pressure change, each assembly 300 is provided with a rupture disc 366 having an appropriate pressure rating that differs from the other assemblies 300. In at least some of these embodiments, all springs 280 have the same spring constant. Some embodiments include a rupture disc 366 having a pressure rating of selected from the group of pressure values consisting of: 200; 500; 1,000; 1,500; and 2,000 pounds per square inch (psi), as examples. Some embodiments include a rupture disc 366 having a pressure rating outside this group of pressure values, within suitable engineering limits, while some other embodiments include a rupture disc 366 having a pressure rating that lies between two of the values listed above, for example, a value of 1,255 psi.

[0068] During operation, assembly 300 remains unchanged while a normal operating pressure Pl exists within bore 136. Exposed to pressure Pl, disc 366 remains intact, and piston 350 remains in a deactivated position, as shown in Figure 8. If the pressure of a fluid in bore 136 rises to a selected activation pressure P2 of disc 366, as may occur due to a fluid leak passing through a packing element 170A,B, then disc 366 will rupture. After disc 366 ruptures, fluid pressure from bore 136 exerts a force on the wettable face area of shoulder portion 356, causing piston 350 and magnet 284 to respond by moving outward to an activated position in which magnet 284 is located within the sensing range of sensor 120.

[0069] In at least some embodiments, by selecting an appropriate combination of pressure rating for rupture disc 366, spring constant for spring 280, and wettable face area of shoulder portion 356, piston assembly 300 is configured for piston 350 to move promptly between two discrete locations (e.g. a deactivated position and a fully activated position) without stopping or without pausing at an intermediate position. This configuration can be achieved, for example, by choosing a spring with a sufficiently low spring constant as compared to the pressure rating of the burst disc 366. For example, piston assembly 300 can be configured such that the pressure that can burst the disc 366 can easily overcome the resistance of the selected spring 280. In an example, the two discrete locations are the innermost deactivated position shown in Figure 8 and an outermost activated position of piston 350 (similar to Figure 7). For at least some embodiments, when assembly 300 is configured for discrete positioning of piston 350 and magnet 284, the signal from sensor 120 is cleaner, providing a binary response as pressure rises from Pl to P2, whether slowly or quickly, because magnet 284 is either positioned outside the range of sensor 120 or within the range of sensor 120.

[0070] Without regard to the pressure rating of a burst disc 366, the wettable face area of shoulder portion 356 of piston 350 is initially equal to the cross-section area of bore 361 of end cap 360. The force exerted on piston 350 is proportional to cross-section area of bore 361 multiplied by the fluid pressure of a fluid acting on portion 356. If this force is sufficient to overcome spring 280 and cause piston 350 to move, then the entire end face of portions 356 will become wetted. This increase in wetted area results in the same pressure exerting a larger force on piston 350, causing piston 350 to move faster or further in opposition to spring 280. This property of piston assembly 300 may also be used to configure for piston 350 to move promptly between two discrete locations (e.g. the innermost, deactivated position and a fully activated position) without stopping or without pausing at an intermediate position) and may result in a more-defined response from sensor 120.

[0071] Referring to Figure 9, in an exemplary embodiment, a rotating control device (RCD) 400 extends along a central axis 401 and is configured to receive sealingly a tubular member along axis 401. Figure 9 shows a close view of the upper portion of RCD 400. Device 400 is suitable as a member of a wellhead over a borehole of a well, such as a hydrocarbon well, and may be used in place of device 100 or in addition to device 100. Device 400 includes an outer housing 410 holding a sensor 420 at a selected position along axis 401 and includes a rotating sleeve assembly (RSA) 425 received within housing 410. RSA 425 holds a pressure- responsive assembly within the detection range of sensor 420, at least during a portion of the rotation cycle of RSA 425. In this embodiment, the pressure-responsive assembly is a transducer 490 that senses pressure and wirelessly transmits an electrical signal that is representative of the sensed pressure. Transducer 490, which includes an internally disposed pressure-responsive element, is configured to measure a property of a fluid within RSA 425 periodically or steadily and to produce wireless communication response corresponding to the measured values. Transducer 490 is selected from a group consisting of: a pressure sensor, a temperature sensor, a flow meter, a viscometer, and a pH meter, as examples. In Figure 9, transducer 490 includes a pressure sensor configured to measure pressure over a range of possible pressures in bore 136 and to transmit a periodic or steady wireless response including pressure data. Sensor 420 is configured as a transceiver to receive the wireless response including data from transducer 490 and to generate a second response based on that response from transducer 490. Sensor 420 is configured to transmit the second response by wire or wirelessly to a controller or another device configured to display, store, evaluate, distribute, or otherwise utilize the data from transducer 490. In at least some embodiments, sensor 420 is also configured to exchange (send or receive) other information with transducer 490. This“other information” may include, as examples, any of the following: calibration information, diagnostic information, a power on/off signal, and a sleep/wake signal.

[0072] Housing 410 is similar to housing 110 of device 100 described in reference to Figure 1. For example, continuing to reference Figure 9, housing 410 includes a housing wall or tubular body 111 extending along the central axis 401, having a through-bore 114. Through- bore 114 is centered on axis 401 and defines an inner wall. Housing 410 includes a sensor port 116 extending through tubular body 111 to the through-bore 114. A sensor 120, as previously described, is disposed in sensor port 116, extending toward the through-bore 114. In addition, housing 410 includes a port 416 to receive the sensor 420. Port 416 extends through tubular body 111 to the through-bore 114. Sensor 420 extends from an inner end 422 adjacent the through-bore 114 to an outer end 423 adjacent the outer surface of housing 410. In Figure 9, port 416 extends radially with respect to axis 401 and is axially spaced apart from port 116.

[0073] Rotating sleeve assembly (RSA) 425 is similar to RSA 145 of device 100. For example, RSA 425 extends at least partially within the through-bore 114 of housing 410 and includes a rotatable sleeve 430, configured to rotate about central axis 401 relative to the housing 410. Sleeve 430 is received within a bearing assembly 180, as described above, to rotate about axis 401. RSA 425 also includes a speed indicator 131, which includes a magnet in this example, received in sleeve 430 at a location along axis 401 that is aligned with sensor 120 in outer housing 410. In addition, sleeve assembly 425 includes a transducer 490 received in sleeve 430 at a location along axis 401 that allows transducer 490 to communicate with sensor 420 during at least a portion of a revolution of sleeve 430.

[0074] Like sleeve 130, rotatable sleeve 430 includes a sleeve outer surface 134 and a bore 136 extending along central axis 401 with packing elements coupled adjacent each end of sleeve 430. In Figure 9, rotating sleeve 430 is formed from multiple members coupled. An upper packing element 170A is shown extending downward from the bottom of an upper collar 168, into member 140. Collar 168, the packing elements, and bore 136 provide a sealable through-passage for a tubular member, to extend into or pass through the housing 410, which in some arrangements leads into a borehole. Bore 136 is configured to be an isolated chamber when a tubular member is installed.

[0075] Like sleeve 130, sleeve 430 includes a radially protruding annular shoulder 146 and a port 148 extending into shoulder 146. Port 148 is aligned with sensor port 116 along axis 401. Port 148 is configured to receive speed indicator 131 at a fixed radial distance from axis 401 and being generally flush or adjacent to outer surface 134. Whenever sleeve 430 rotates the indicator 131 to the circumferential position of speed sensor 120, the magnet of indicator 131 is at a fixed distance from speed sensor 120 within its detection range (e.g. a prescribed distance).

[0076] Sleeve 430 also includes a sensor port 452 extending from an outer port-end 453 at the bottom of shoulder 146 to an inner port-end 454 that intersects bore 136. In Figure 9, port 453 includes a 90° turn. A first end 492 of transducer 490 is located within port 452. A second end 493 of transducer 490 is located outside and adjacent the outer port-end 453, extending below shoulder 146. Transducer 490, including its pressure-responsive element, is in fluid communication with bore 136. As shown, a first portion of port 452 and wireless transducer 490 extend parallel to axis 401 for greater clearance of second end 493, meaning the exposed length of end 493 is not limited by the radial distance between shoulder 146 and the adjacent portion of housing 410. The exposed second end 493 of transducer 490 is disposed at a location that gives transducer 490 a wireless communication path to the inner end 422 of sensor 420. For example, in Figure 9, the exposed second end 493 of transducer 490 is disposed along axis 401 adjacent the axial location of inner end 422 of sensor 420, placing transducer 490 in the“line-of-sight” of sensor 420 during at least a portion of the revolution of sleeve 430. During at least a portion of the revolution of sleeve 430, transducer 490 communicates wirelessly with sensor 420 to provide data related to a property of a fluid that is in bore 136, which in this example is pressure.

[0077] Figure 10 shows a method 500 for operating a rotating control device configured for use in an oil well system. Method 500 is applicable for operating an RCD 100, 400, as examples. At block 502, method 500 includes providing a housing having a through-bore extending along a central axis, a housing wall, and a sensor disposed at a sensor position in the housing and extending into the housing wall. Block 504 includes disposing a sleeve within the through-bore of the housing, the sleeve comprising a sleeve bore aligned with the central axis and configured to rotate about the central axis. Block 506 includes providing a pressure-responsive assembly that includes a pressure-responsive element configured to be free of sliding engagement with the sleeve. Block 508 includes coupling a pressure- responsive assembly to the sleeve at a location such that the pressure-responsive assembly passes the sensor position periodically as the sleeve rotates within the through-bore and such that the pressure-responsive element is in fluid communication with the sleeve bore. Block 510 includes disposing a tubular string sealingly within the sleeve bore.

[0078] Block 512 includes rotating the tubular string and the sleeve with respect to the housing, as may be accomplished by a rotary table, for example. Block 514 includes operating the sensor to detect a response of the pressure-responsive assembly when pressure in the sleeve bore reaches an activation pressure. Block 516 includes performing a system action when the sensor detects a response of the pressure-responsive assembly. Various embodiments of method 500 may include fewer operations than described, and other embodiments of method 500 include additional operations.

[0079] Although various embodiments disclosed herein included multiple pistons 250, 350 with each piston coupled to and potentially driven by a spring 280 having a same spring constant as the other springs 280, in some embodiments, a spring coupled to a piston has a different spring constant than does another spring that is coupled to a different one of the multiple pistons. In some embodiments, a first piston is coupled to a spring having a first spring constant, and a second piston is coupled to a spring having a different spring constant, and both pistons have the same neck area or end area exposed to fluid in sleeve bore 136. The first and second pistons respond to different activation pressures on account of the different springs rather than differences in area exposed to bore 136.

[0080] In place of magnet 284, some embodiments include another type of detectable portion or element on a piston 250, 350, corresponding to the sensing capability of sensor 120, as discussed above.

[0081] Referring again to Figure 9, in some embodiments, sensor 420 is also configured to display, store, evaluate, or otherwise utilize the data from transducer 490 in addition to distributing a response. In some embodiments, transducer 490 is a pressure switch, configured to respond to a prescribed value of pressure in bore 136 similar to the response of a piston assembly 200, 300. Some embodiments include multiple transducers 490 installed in a rotating sleeve 430. [0082] While exemplary embodiments have been shown and described, modifications thereof can be made by one of ordinary skill in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations, combinations, and modifications of the systems, apparatuses, and processes described herein are possible and are within the scope of the disclosure. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. The inclusion of any particular method step or operation within the written description or a figure does not necessarily mean that the particular step or operation is necessary to the method. The steps or operations of a method listed in the specification or the claims may be performed in any feasible order, except for those particular steps or operations, if any, for which a sequence is expressly stated. In some implementations two or more of the method steps or operations may be performed in parallel, rather than serially.