CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to co-pending U.S. Provisional Patent Application

No. 62/064,819 filed on October 16, 2014, the entire content of which is incorporated herein by reference.

BACKGROUND

[0002] A reciprocating compressor is a positive displacement machine wherein a piston draws compressible fluid into a cylinder on a down stroke and discharges compressible fluid by compressing the compressible fluid on the upstroke. Multiple reciprocations of the piston cause a volume of compressible fluid to be discharged. The fluid can be exhausted into a fixed volume holding tank thereby increasing the pressure inside the holding tank. The piston, in this application, continues its reciprocation until a desired pressure is reached in the holding tank. As the compressible fluid inside the holding tank is discharged out of the holding tank, the piston is reciprocated as needed to maintain a desired operating pressure. The fluid when discharged from the tank can be used in various applications.

[0003] Components for reciprocating compressors can include a valve that allows the fluid to flow into a cylinder on the down stroke and a valve that allows the compressible fluid to exhaust out of the cylinder during the upstroke. The valves experience many cycles during their operating life and when a valve fails or begins to cease to operate effectively, the efficiency and effectiveness of the compressor significantly deteriorates. Figures 1 and 2 illustrate a prior configuration of a concentric valve head assembly 100 engageable, as a retrofit, with a cylinder head 101. The head assembly 100 and the retrofit of the head assembly 100 to cylinder 101 are disclosed in WO 2013/070330 Al . The head assembly 100 includes valve head 103. A seal 105 is between head 103 and cylinder 101. The valve head 103 can also be called a cylinder head 103. The head has an intake port 107 and a discharge port 109. A concentric valve 111 is housed within the valve head 103. A valve clamp 113 secures concentric valve 111 within valve head 103 and is secured to the head 103 with fasteners 115. Seals 117 establish a sealing engagement between the clamp and the head. Valve head 103 is removably coupled to cylinder 101 with head fasteners 119. The head 103 replaces, as a retrofit, another type of head as shown and described in WO 2013/070330 Al .

SUMMARY

[0004] In one aspect, a two way concentric valve head assembly has a sidewall which has a side surface which delimits a hollow in an interior of a two way concentric valve head. An intake port opens through the sidewall and into an intake channel. A discharge port opens through the sidewall from a discharge channel. An inclined structure delimits the intake channel. An interface also delimits the intake channel and is in sealing engagement with the inclined structure. A path traversing an entirety of an axially delimiting perimeter of the inclined structure is curved; a line joining opposite sides of the path is angled relative to a central axis of the head at an angle of at least 104 degrees. In any event it is more than 90 degrees.

[0005] In another aspect, a two way concentric valve head has a sidewall which has a side surface which delimits a hollow in an interior of the two way concentric valve head. An intake port opens through the sidewall and into the hollow. A discharge port opens through the sidewall. An inclined structure is continuous about a central axis of the head and delimits the hollow. The inclined structure forms a continuous delimiting perimeter about the axis. A continuous path traversing the continuous perimeter of the inclined structure is oblong, and a major axis of the oblong path is angled relative to the central axis of the head at an angle of at least 104 degrees. In any event it is more than 90 degrees.

[0006] In another aspect, an interface is adapted for sealing engagement with a two way concentric valve head. The interface is inclined and continuous about a central axis and has a continuous perimeter about said axis. A continuous path traversing the continuous perimeter of the inclined structure is oblong, and a major axis of the oblong path is angled relative to said central axis at an angle of at least 104 degrees. In any event it is more than 90 degrees. The central axis is a central axis of a sphere having a diameter formed along the major axis of the oblong path. The diameter of the sphere is the diameter of the oblong path taken along the major axis. [0007] In another aspect, a two way concentric valve head assembly includes a valve head supporting a two-way concentric valve. The valve head has a sidewall having an intake port and a discharge port and defining a hollow interior having an surface sloped relative to a central axis of the valve head and extending radially inwardly from an interior surface. A valve clamp includes an intake channel fluidly coupled to the intake port, a discharge channel fluidly coupled to the discharge port, and an interface in sealing engagement with the sloped surface to divide the intake channel and the discharge channel.

[0008] Other features and aspects of the disclosure will become apparent by

consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a perspective view of a prior art embodiment of a two way concentric valve head assembly engageable with a cylinder.

[0010] FIG. 2 is a cross-section of the prior art embodiment of the two way concentric valve head assembly taken along the view line 2-2 of FIG. 1.

[0011] FIG. 3 is an isometric view of a cross section of a two way concentric valve head assembly; the section is taken along an axis of the valve head of the assembly.

[0012] FIG. 4 is a first side facing view of the cross-section of the valve head of the two way concentric valve head assembly of FIG. 3.

[0013] FIG. 5 is an isometric view of a cross-section opposite the cross-section of the valve head of the two way concentric value head assembly of FIG. 3, with the section taken along the axis of the valve head.

[0014] FIG. 6 is a first end isometric view of the valve head of the two way concentric valve head assembly of FIG. 3.

[0015] FIG. 7 is a first side facing view of a cross-section of the valve clamp of the two way concentric valve head assembly of FIG. 3, with the section taken along an axis of the valve clamp. [0016] FIG. 8 is an isometric view, of a cross-section opposite the cross-section of FIG. 7 of the valve clamp of the two way concentric valve head assembly of FIG. 3, with the section taken along the axis of the valve clamp.

[0017] FIG. 9 is a first end isometric view of the valve clamp of the two way concentric valve head assembly of FIG. 3.

[0018] FIG. 10 is a first end isometric view of a cross-section of the valve of the two way concentric valve head assembly of FIG. 3.

[0019] FIG. 11 is a schematic drawing of an inclined structure of the valve head taken along the central axis of the valve head; axes indicate a major axis and a central axis of the inclined structure.

[0020] FIG. 12 is a schematic drawing of an interface adapted for sealing engagement with the inclined structure of FIG. 11, in which the interface is inclined relative to a central axis of a valve clamp; the schematic shows the major and central axis of the of the interface.

[0021] Before any embodiments are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of supporting other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

[0022] The following detailed description references the accompanying figures that illustrate specific embodiments. The embodiments are intended to describe aspects in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the invention. The description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. [0023] FIG. 3 provides an example of a removable concentric valve head assembly 200 that fits with a reciprocating compressor piston cylinder, like cylinder 101. It can, of course, be used to retrofit a cylinder in a manner as described in WO 2013/070330 Al . It can be used to retrofit cylinder 101 and replace head assembly 100 with assembly 200. It can also be used to fit with a cylinder as an original equipment part. The concentric valve head assembly 200 includes a valve head 202; a concentric valve 204 housed within valve head 202; and valve clamp 206 that secures concentric valve 204 within valve head 202. Valve head 202 can also be called cylinder head 202. The clamp 206 and head 202, as explained more fully below, are in sealing engagement with each other and each have surfaces and structures which delimit an intake channel 208 and a discharge channel 210 which are fluidly sealed off from one another. The intake channel 208 and discharge channel 210 are in an interior of the head 202. The

compressible fluid, such as ambient air, travels along a flow path in the intake 208 channel delimited by the head 202 and valve clamp 206. It flows through valve 204. From the valve 204 it enters the cylinder, such as cylinder 101. The fluid exits the cylinder and valve 204. After it exits from valve 204 it travels along a flow path in the discharge channel 210 and exits out of the head 202.

[0024] As explained in more detail below, the head assembly 200 has an inclined, continuous, and elliptical structure or sloped surface 232 at the interior of the head and delimiting the intake 208 and discharge channel 210. It further has an inclined structure 238 delimiting intake port 234 which opens into intake channel 208. Also it has an inclined, continuous and elliptical interface 250 in sealing engagement with structure 232 and carried by a part of valve clamp 206. The structures allow for the discharge channel 210 to have a larger volume proximate a discharge entry 236a of discharge port 236 than the volume proximate the entry in the previous removable two way concentric valve head design. They also allow for a central portion of an exit 234b of intake port 234 to be less offset in the axial direction from a central portion of the entry 236a of the discharge port 236 than in the previous two way removable concentric valve head design. The head 202 of the present configuration has significantly less weight than the previous removable two way concentric valve head design. It also has a significantly smaller height, as measured in an axial direction from a first end 224 to a second end 228 of the head 202 than the previous removable two way concentric valve head design.

[0025] Now in more detail, the head 202 has a first side 212, which is an exterior side, formed by a sidewall 214. The head has a second side 216. The second side 216 is an interior side. The second side 216 is opposite the first side 212 and is formed by sidewall 214. The interior side 216 delimits the interior of the head. The second side 216 has a first side surface 218 which delimits a hollow 220 in the interior of the head. The delimiting includes the radial direction. Surfaces other than surface 218 delimit the hollow. The first surface 218 forms a perimeter delimiting the hollow in the radial direction. It is around and about head central axis 230. The intake channel 208 and discharge channel 210 are merged into and formed from and with the hollow. They are at the interior of the head 202. The hollow 220 has a first opening 222 which opens through a first portion of the head. The first portion can be called an upper portion of the head. The opening 222 is through the first end 224 of the head. The first end is at a top of the head. The hollow 220 has a second opening 226 which opens through a second portion of the head. The second portion can be called a lower portion of the head. The opening is at the second end 228 of the head which is at a bottom of the head. The first 224 and second 228 ends are axially spaced. The central axis 230 passes through the hollow 220, first opening 222 and second opening 226. The axis 230 passes through a center of the first 222 and second 226 opening. The upper and lower portions of the head overlap the side wall 214. The intake port 234 and discharge port 236 are at and open through the first 212 and second 216 side, the sidewall 214 and surface 218. They open into the hollow 220. The intake port 234 opens into the intake channel 208. The discharge port 236 opens out of discharge channel 210. A straight line extending into the intake 234 and discharge 236 port intersects axis 230. The intake 234 and discharge 236 port are formed without, exclusive of and separate from the first 222 and second 226 opening.

[0026] The inclined structure 232 and interface 250 are in sealing engagement when the interface 250 is in operational engagement with the valve head 202. The sealing engagement fiuidly seals the intake channel 208 from the discharge channel 210. Interface 250 has a first end 251. It also has a second end 253 opposite the first end in an axial direction. The interface 250 can be called a flange. The interface 250 is carried by and part of the valve clamp 206. [0027] A guide 252 is joined to the interface 250. The guide 252 has a receiver 257 at a first end 258 of the guide 252. The guide 252 is joined to the interface 250 at the receiver 257. The receiver can be called a mouth 257. The receiver leads to an interim portion 255 of the guide. The guide 252 also has a base portion 254 which forms a valve sealing portion. The base portion 254 is at a second end 256 of the guide 252. The interim portion 255 is between the mouth 257 and base 254. The guide 252 also delimits the intake channel 208 and the discharge channel 210. It delimits in both the axial and radial direction.

[0028] Now in more detail, the inclined structure 232 is between said first side 212 and said axis 230. It is at the interior of the head 202. It delimits a portion of the hollow 220. It delimits a portion of the hollow 220 in the radial direction. It also delimits a portion of the hollow 202 in the axial direction. The inclined structure 232 surrounds the portion of the hollow 220 it delimits in the radial direction and forms a void space. The surrounding is continuous. It forms an oblong, oval and elliptical perimeter about the void space. The inclined structure has a first open end 242 and an opposite second open end 244 axially spaced from the first open end 242. Each open end opens into the area of the hollow, void space, delimited by the inclined structure in the radial direction. Inclined structure 232 extends in a direction away from the first surface 218 and towards the axis 230. The direction of extension can be said to be a radial direction. Structure 232 is integral with and seamless with the first surface 218. It extends from the first surface 218. The inclined structure 232 is continuous about and around the axis 230. It is oblong and oval. It is elliptical. It is between intake 234 and discharge 236 ports. The inclined structure 232 extends from proximate intake port 234 to proximate discharge port 236. The inclined structure 232 delimits the intake channel 208 and the discharge channel 210. It delimits the intake 208 and discharge 210 channels in the axial direction. It also cooperates with the interface 250 to fluidly seal off the fluid in the discharge channel 210 from the fluid in the intake channel 208. Thus it cooperates to fluidly seal the discharge channel 210 from the intake channel 208. The intersection of structure 232's long and short axis is eccentric to axis 230. The inclined structure can be said to be eccentric to axis 230. A path can be drawn traversing the entirety of a portion of the inclined structure which is continuous about and around axis 230. The continuous portion traversed can be at and follow a continuous perimeter which is about and around the axis 230. It can be a radially delimiting perimeter or an axially delimiting perimeter of the inclined structure. The path is oblong, oval and elliptical and continuous about and around the axis 230. The path lies in a single plane. The plane in which the path completely lies, and the major axis of the oblong path, are each angled relative to the axis 230 at an angle 246 of 106 degrees. The angle should be between 104 and 108 degrees and at least 104 degrees. A central axis of the oblong formed by the structure or path is angled relative to the axis 230 at an angle 248 of 16 degrees. The angle should be between 14 andl8 degrees and at least 14 degrees. The axis of the oblong is through the intersection of the major and minor axes of the oblong and perpendicular to both. Put another way, the inclined structure, along a straight line drawn in a direction form the intake port to the discharge port and to span across the void space delimited by the structure and to intersect opposite sides of the structure, is angled relative to the axis 230 at an angle of 106 degrees. The angle should be between 104 and 108 degrees and at least 104 degrees. In any event it is more than 90 degrees. Although the axis 230 forming the angles in connection with the inclined structure has been defined relative to the head, it can also be defined relative to the inclined structure 232. Axis 230 can be the central axis of a sphere having a diameter formed along the major axis of the ellipse or oblong formed by the path or structure. The sphere's diameter is the diameter (length) of the oblong or ellipse taken along its major axis. The sphere is formed with the oblong or ellipse. The inclined structure 232 can be called a flange, a partition, a border, and a guide.

[0029] Now in more detail, the interface 250 is inclined, oblong, oval and elliptical. It is continuous about and around axis 260. It delimits the intake 208 and discharge 210 channels. It delimits in the axial direction. The interface 250 is proximate the inclined structure 232 when the interface 250 is in operational engagement with the head 202. The interface 250 is joined to, integral with, and seamless with the receiver 257 of the guide 252 at a surface of the mouth which delimits the intake channel 208. A path can be drawn traversing the entirety of a portion of the interface 250 which is continuous about and around axis 260. The continuous portion can be at and follow a continuous perimeter about and around the axis 260 such as a radially delimiting perimeter or an axially delimiting perimeter of the interface 250. The path is oblong, oval and elliptical and continuous about and around axis 260. The path lies in a single plane. The plane in which the path completely lies, and the major axis of the oblong path, are each angled relative to axis 260 at an angle 261 of 106 degrees. The angle should be between 104 and 108 degrees and at least 104 degrees. In any event it is more than 90 degrees. A central axis of the oblong extending in the axial direction through the intersection of the oblong's major and minor axes and perpendicular to both is angled relative to the axis 260 at an angle 263 of 16 degrees. The angle should be between 14 andl8 degrees and at least 14 degrees. Put another way, the interface 250 is inclined along a straight line spanning across the opposite sides of interface 250 from an intake side 265 of the interface to a discharge side 267 of the interface. The interface 250 along the line is angled relative to the axis 260 at an angle 261 of 106 degrees. The angle should be between 104 and 108 degrees and at least 104 degrees. In any event it is more than 90 degrees. The discharge side 267 of the interface is the portion of the interface at the discharge side of the head, and the intake side 265 is the side at the intake side of the head when the interface 250 is in operational engagement with the head 202. The axis 260 is the central axis of the valve clamp and is coextensive with the axis 230 when the head and clamp are in operational engagement. Although axis 260 is the axis of the valve clamp it can also be defined relative to the interface 250. It is the central axis of a sphere having a diameter formed along the major axis of the ellipse or oblong formed by the path or structure. The diameter of the sphere is the diameter (length) of the oblong or ellipse taken along its major axis. The sphere is formed with the oblong or ellipse.

[0030] Structure 238 delimits a portion of the intake port 234. It extends in a direction away from entry 234a into the intake port 234 and towards axis 230. The structure 238 comprises a first inclined surface 238a and a second inclined surface 238b. Each surface 238a and 238b is inclined and extends to intake exit 234b of intake port 234 and beyond the exit 234b towards axis 230. Each surface delimits said hollow 220. Each surface is oppositely facing. Surface 238a faces towards the first end 224 of head 202 and surface 238b faces towards second end 228 of head 202. Each surface 238a and 238b is angled relative to the axis 230 at an angle of 130 degrees. The angle should be between 128 and 132 degrees and at least 128degrees. The oblique structure 232 joins to the inclined port delimiting surface 238a. It can be joined at a rounded junction. The structure 232 and surface 238a are integral and seamless with each other.

[0031] Inclined structure 232, inclined interface 250 and inclined structure 238 of intake port 234 cooperate to create a less tortured flow path with fewer obstacles than were present in the previous design. For instance there is no step between discharge port entry 236a and exit 236b. There is no surface redirecting or diverting the path of any of the fluid between the entry 236a and exit 236b of the discharge port. There is no surface redirecting or diverting the path of any of the fluid between the entry 236a and exit 236b of the discharge port to travel at an incline of more than 3 degrees relative to a plane perpendicular to and intersecting axis 230. There is no surface between the entry 236a and exit 236b of the discharge port inclined at an angle of more than 3 degrees relative to the plane perpendicular to and intersecting axis 230. With respect to the intake port 234, there is no surface re-directing or diverting the path of any of the fluid between the entry 234a and exit 234b of the intake port 234 to travel at an incline of more than 40 degrees relative to the plane perpendicular to and intersecting axis 230. There is no surface between the entry 234a and exit 234b of the intake port 234 inclined at an angle of more than 40 degrees relative to the plane perpendicular to and intersecting axis 230. Also, the offset between the central portion of exit 234a and entry 236a is no more than 2 percent of the maximum inner diameter, ID, of head 202. The maximum inner diameter is delimited by surface 218.

[0032] With respect to the intake 208 and discharge 210 channel, they have increased volume where most needed, proximate their respective intake 234 and discharge 236 ports. The intake channel volume delimited by the head and/or interface and/or guide on the intake side of the head is at least 1.2 times the intake channel volume delimited by the head and/or interface and/or guide on the discharge side of the head. This means the intake channel volume delimited by the inclined structure 232 on the intake side of the head is at least 1.2 times the intake channel volume delimited by the inclined structure on the discharge side of the head. Also the discharge channel volume delimited by the head and/or interface and/or guide on the discharge side of the head is at least 1.2 times the discharge channel volume delimited by the head and/or interface and/or guide on the intake side of the head. The discharge channel volume delimited by the inclined structure 232 on the discharge side of the head is at least 1.2 times the discharge channel volume delimited by the inclined structure on the intake side of the head. The intake side of the head is a section of the head completely forming the intake port 234. The discharge side of the head is a section of the head completely forming the discharge port 234. The sections fall on opposite sides of a plane coextensive with axis 230. The plane is also coextensive with an axis perpendicular to axis 230. The perpendicular axis extends between the intake and discharge port. The plane divides the head in half. The axis perpendicular is coextensive with the minor axis of the oblong formed by surface 218. The sections of the head each form a head half.

[0033] Further the head when assembled with the valve clamp and valve has a total gas volume which includes the total intake gas volume added to the total gas discharge gas volume. The ratio of the total intake gas volume is total gas volume of the head is at least 1.2. The ratio of the total discharge volume to the total volume of the head is at least 1.75.

[0034] The change in volumes improves compression efficiency by requiring less work to draw fluid into and out of the cylinder, such as cylinder 101. The efficiency improves, at least in part, because the configuration serves to reduce the pressure drop between intake port 234 and discharge port 236 of the valve head assembly 200 thereby reducing the energy needed to operate the compressor. It also reduces the amount of heat generated from fluid flow during operation.

[0035] The improvement means the height of the compressor measured in the axial direction from head first end 224 to head second end 228 can be reduced from the previous design while maintaining the same or a little bit better efficiency of the previous design. The reduction in height translates to a reduction in weight. The ratio of the height of the head 202 to a maximum ID of the head is no more than 0.4. The ratio of the height of the head 202 to a maximum ID of the cylinder for which the head is adapted to fit, such as cylinder 101 is no more than 1. The weight of the head in kilos is no more than 27 kilos to fit a cylinder having a max ID of no less than 5.5 inches. The maximum ID of head 202 is delimited by surface 218.

[0036] Now referring back to the inclined structure 232 in more detail, the inclined structure 232 has a surface 232b delimiting the intake channel 208 in the axial direction. The surface 232b, facing in a direction away from the second opening 226 and towards the first opening 222, is inclined like the structure it forms, is elliptical, continuous about and around axis 230, and proximate to intake port 234 and to discharge port 236. The surface 232b is joined to, integral with, and seamless with a portion of the head first surface 218. The inclined structure has a surface 232c facing in a direction away from the first opening 222 and towards the second opening 226. It is inclined like the structure it forms, is elliptical, continuous about and around axis 230. It is proximate to the intake port 234 and the discharge port 236. The inclined surface delimits a portion of the discharge channel 210 in the axial direction. The surface is joined to, integral with and seamless with a portion of the head first surface 218. Surface 232a formed by inclined structure 232 is oblong, oval, continuous about and around axis 230, and elliptical. It is joined to, integral with, seamless with, and between surface 232b and surface 232c. It is proximate to intake port 234 and discharge port 236. It is inclined like the structure it forms. The surface 232a delimits the hollow 220 in the radial direction and faces towards axis 230. It surrounds and delimits the void space having openings 242 and 244.

[0037] The interface 250 has a surface 250b which is inclined, continuous about and around axis 260, oblong, oval, and elliptical, and faces away from the interface second end 253 and in the axial direction. The surface 250b is proximate and coupled to the surface 250a of interface 250. It is seamlessly coupled. The surface 250b is proximate to and in fluid connection with the surface 232b of inclined structure 232 when the interface 250 is in operational engagement with head 202. The interface 250 has a surface 250c and a surface 25 Oe which are each inclined, oblong, oval, elliptical, and continuous about and around axis 260. Each faces away from first end 251 and in the axial direction. Surface 250c is joined with, integral with, and seamless with a surface 25 Od of the interface 250. Surface 25 Od is oppositely facing from surface 250a. Surface 25 Oe is proximate to surface 250a. Surface 250a faces in the radial direction. Surface 250a is inclined, oblong, oval, elliptical, and continuous about and around axis 260. Surface 250a faces and is proximate surface 232a of the inclined structure 232. A deformable and resilient member 286, such as an O-ring, in a groove 288 establishes the sealing engagement between the interface 250 and inclined structure 232. The grove 288 is formed with surface 250a. The deformable member 286 is between the inclined structure 232 and interface 250 and surface 250a and surface 232a. The sealing engagement seals off the fluid in the intake channel 208 from the fluid in the discharge channel 210.

[0038] Surfaces 325a, 325b delimiting a portion of the discharge channel 210 have first ends which are proximate entry 236a of discharge port 236. The surfaces 325a, 325b at a second end are distal from the entry 236a. The surfaces 325a and 325b each extend from the first to the second ends. The portion of each surface at the first end is further from the axis 230 in the radial direction than the respective portion of each surface at the second end. The portion of surface 235 a at the first end proximate entry236a and the portion of surface 235b at the first end proximate entry 236a are on opposite sides of entry 236a. Each of surfaces 325a and 325b form part of first surface 218.

[0039] Surface 218 also includes surfaces 326a and 326b. The surfaces 326a and 326b are arranged relative to the intake port exit 234b in the same manner as surfaces 325a and 325b are arranged, as described above, relative to the discharge port entry 234a.

[0040] Now referring to further structure of the assembly, a first plurality of legs 270 couples a head 272 of the valve clamp 206 to the interface. A second plurality of legs 274 joins the interface 250 to a base 276 of the valve clamp 206. The valve base 276 is a valve engagement structure of the valve clamp 206. The first legs 270 extend between the interface 250 and the valve clamp head 272. Each of the first legs 270 at a leg first end 270a is joined to, integral with, seamless with and terminates into the interface 250. Each of the first legs at a second end 270b is joined to, integral with, seamless with and terminates into an insert 272a of the clamp head 272. The first plurality of legs 270 is spaced apart about and around the axis 260 of the valve clamp. A void space is between each adjacent pair of spaced apart legs 270. The void spaces are merged with the hollow 220 and form part of the intake channel 208. The second plurality of legs 274 is spaced apart and about and around the axis 260. A void space is between each adjacent pair of the spaced apart second legs 274. The void spaces are merged with the hollow 220 and form part of the discharge channel 210. The second legs 274 extend between the interface 250 and the base 276. Each of the second legs at a leg first end 274a is joined to, integral with, seamless with and terminates into the interface 250. Each of the legs 274 at a second end 274b is joined to, integral with, seamless with and terminates into the base 276.

[0041] Insert 272a of the valve clamp is a head engagement structure. The insert 272a is axially spaced from the interface 250. When the interface is in operational engagement with the head 202, the insert 272a is proximate the head 202 and a surface 278 of the head 202. It is in sealing engagement with the head at the surface 278. The surface 278 is a second surface of the head. The second surface 278 is proximate the head first opening 222. It is part of the first portion of the head. A deformable and resilient member 280, such as an O-ring, in a groove 282 of the insert 272a establishes the sealing engagement with the second surface 278. The grove is formed with a surface 284 of the insert facing away from the axis and towards the second surface 278. The surface facing away 284 is proximate the second surface 278. The deformable member 280 is between the insert 272 and second surface 278 of the head. More particularly it is between the surface 284 and surface 278. The sealing engagement seals off the fluid in the hollow 220 from the environment, such as atmospheric pressure. More particularly it seals off the fluid in the intake channel 208 from the environment such as pressure at atmosphere. Thus it fluidly seals intake channel 208 from atmosphere. As stated the deformable member 286 in groove 288 is between surface 250a and surface 232a. The deformable and resilient members 280, 286 are interchangeable. The grooves 282, 288 may be machined using two separate methods. A simple lathe will be sufficient to machine the groove 282 in insert. However, because of the angled and elliptical configuration of interface 250 about axis 260, surface 250a cannot be machined using a simple turning method or lathe. Therefore, the use of a computer numerical control (CNC) machine is suggested for manufacturing the eccentric groove 288 in surface 250a.

[0042] The base 276 holds the two way concentric valve 204 in place on a head seat 290.

The head seat 290 is at the lower portion of head 202 and proximate head second opening 226. The head seat is formed in a separate piece from the portion of the head having the intake and discharge port and intake channel and discharge channel. An O-ring 340 seals the seat piece to the rest of the head. An O-ring 341 seals valve 204 to a sidewall of seat 290. The base 254, valve sealing portion, is in sealing engagement with valve 204. A seal 292, such as a flat gasket type seal, between base 254 and valve 204 establishes the sealing engagement between the valve and base 254. The guide at its base 254 seals off fluid from and partitions the valve intake portion 204a and the discharge portion 204b of the valve. The intake portion 204a of the valve forms the valve intake and it is rimmed by the discharge portion 204b of the valve. The discharge portion 204b forms the discharge of the valve 204. Fluid enters the valve 204 at the intake and exits the valve at the discharge. Concentric valve 204 is a single modular element that performs dual functions and replaces the necessity of two one way valves. Concentric valve 204 is divided into intake portion 204a and a discharge portion 204b. The concentric valve 201 has a circular shape in which intake portion 204a occupying the inner ring of concentric valve 204. Concentric valve 204 includes two circular plates combined in one element. First plate 204c is at the top. Second plate 204d is at the bottom. The two plates can be called circular discs. The construction of concentric valves is known in the art. As shown, a portion of the circular valve plate 204d at the bottom of concentric valve 204 is seated on valve seat 290 which can also be called head seat 290. Valve clamp 206 is inserted within the hollow 220. Valve clamp base 276 holds the valve 204 in place.

[0043] The head 272 of the valve clamp has a top cover 272b that may include coupling tabs. A recessed portion can be between each tab. Apertures 294 extend through the cover 272b at each tab. To secure concentric valve 204 within valve head 202 with valve clamp 206, a plurality of clamp fasteners 296 are inserted through apertures 294 of top cover 272b of valve clamp 206 and into apertures 298 at a surface 300 of the first portion of the head. The surface 300 faces away from the second opening 226; it faces in the axial direction and is proximate the first opening 222 and at the first end 224of the head. The fastener 296 in cooperation with the clamp 206 serve to removably couple valve clamp 206 to valve head 202 and sealingly engage the base 254 of guide 252 with the valve 204 at valve plate 204c and securely engage the valve clamp base 276 to the valve 204 at the valve plate 204c The seal 292 is also between the base 276 and plate 204c. The configuration of the top cover 272b ensures that the fasteners 296 fit in- between head fasteners 302 when fasteners 302 are in an installed position in apertures 304 and the head 202 is coupled to a cylinder such as cylinder 101.

[0044] Still referring to further structure of the assembly 200, the first side 212 of head

202 may include annular ribs 306 around its circumference and may also include vertical ribs 308 spanning substantially from first end 224 to second end 228 of the head. The pattern of ribs 306 and 308 may serve in part to increase the stiffness of sidewall 214. They may also provide for heat exchange with outside air/environment.

[0045] The head assembly may include a pressure unloading assembly which includes a spring loaded actuator 310 whose main function is to move fingers 312 down thus holding the intake portion 204a of valve 204 open and thus stopping the compression process. Air flows back out the intake when the actuator is activated.

[0046] Valve head assembly 200 can be used to retro-fit existing piston cylinders 101 of a reciprocating compressor assembly in figure 1 by replacing valve head assemblies existing with the head. The existing valve head is replaced with the valve head assembly 200 in a manner described in WO2013/070330 Al . [0047] The use of radial, radial direction, radial delimiting, axial, axial direction, axially delimiting are relative to axis 230 and/or 260 depending on context. Something that is radially delimiting is a boundary facing in a direction, either way along, an axis coextensive with a radius. Something that is in the axial direction faces a direction along an axis extending in the direction of axis 230/260. The inclined structures and inclined surfaces referenced herein are oblique relative to axis 230 and 260.

[0048] From the foregoing it will be seen that this invention is well adapted to attain all ends and object hereinabove set forth together with the other advantages which are obvious and which are inherent to the structure.

[0049] It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is

contemplated by and is within the scope of the claims.

[0050] Since many possible embodiments may be made without departing from the scope of the invention, it is to be understood that all matter herein set forth or shown in the

accompanying drawings is to be interpreted as illustrative and not in a limiting sense.