BACKGROUND ART One technique used to drill a wellbore involves rotational drilling in which a drill string is rotated to actuate a drill bit at the remote end of the drill string. The rotating bit cuts through subterranean formations opening a path for the drill pipe that follows. Another technique involves using a motor, as opposed to rotating the drill string, to actuate the drill bit. The motor responds to drilling fluid forced through a central passageway of the drill string to the motor. The drilling fluid exits the motor and returns to the surface via an annular space, or annulus, that is located between the drill string and the wellbore.

It is usually desirable to obtain information about one or more downhole conditions as drilling progresses. For example, it may be desirable to know the wellbore inclination angle, wellbore magnetic heading and/or the tool face orientation of the bottom- hole assembly to ensure that drilling is progressing in the right direction. Other useful information includes radioactivity of the formation to discriminate between sands and shale, resistivity and porosity of the formation to determine if oil is present.

These downhole conditions are typically measured by sensors located as near as possible to the bit. A downhole measurement while drilling (MWD) mud pulser transmits these measurements to the surface of the well by modulating the already present stream of drilling fluid that circulates down the central passageway of the drill string and up through the annulus. Sensor measurements are typically encoded in the stream by selectively restricting the flow of drilling fluid. As a result of these restrictions, the encoded data takes on the form of pressure pulses. Sensors at the surface of the well decode these pressure pulses to recover the downhole information from the mud stream.

Current MWD mud pulsers suffer from a variety of problems associated with leakage and wash out resulting from the use of set screws in the collar wall to hold the actuator assembly in position, mechanical failures on printed circuit boards due to resonant excitation of normal modes of oscillation of the boards and components mounted thereto, as well as expensive and complex construction of the turbine and actuator assemblies resulting from the need to build components capable of withstanding the pressures and stresses applied during their use downhole.

DISCLOSURE OF THE INVENTION In one aspect the invention features a combination of one or more novel components that can be used in an oil well drilling operation. The components include a novel hydraulic system for supplying hydraulic fluid for operating a MWD mud pulser or similar tool, a novel pipe or collar structure for supporting and retaining an actuator assembly at predetermined positions, a novel inlet valve and containing accumulator reservoir combination for supplying fluid to the actuator, a turbine assembly having novel fin and/or stator configuration, a novel electrical connector assembly for electrically connecting the turbine assembly to the actuator assembly, a novel circuit board mounting assembly, and a novel valve assembly.

Another aspect of this invention relates to each of these novel components individually as they may relate to use in a MWD oil tool or in other oil tool equipment. In this aspect, the novel hydraulic system comprises an accumulator provided with a reservoir and a pressure operated, one way inlet valve wherein the valve is structured to permit hydraulic fluid, under pressure, to be added to the reservoir and the accumulator is structured to maintain fluid pressure in the reservoir. The novel collar structure comprises one or more collars which separately or together are provided with two interior shoulder sections, the first for supporting an oil tool, such as connected turbine and actuator assemblies at a first location and the second for retaining the tool at a second location downhole of the first location. The novel turbine assembly for generating rotary power from the flow of drilling fluid through the turbine assembly comprises a stator constructed to have a passageway arranged to receive electrical

wires passing through the turbine assembly, and a rotor mounted for rotation within the stator. In another embodiment, only one of the turbine assembly stator and rotor are constructed having curved fins. The novel circuit board mounting assembly comprises a circuit board mounting body having a mounting surface for receiving the circuit board and a clamping device adapted to engage portions of the circuit board not containing the printed circuit, preferably at least a portion of which shall be the peripheral edges of the circuit board, and most preferably a substantial portion of the peripheral edges, to clamp the circuit board to the mounting surface. The novel valve of the MWD oil tool positioned in a first fluid flowpath comprises a cylinder that has a passageway for a second flowpath and a radial opening that is configured to establish fluid communication between the two flowpaths, a restrictor that is located in the passageway and a control that is adapted to, without entirely blocking fluid communication between the radial opening and the passageway, actuate the restrictor to selectively restrict flow of a fluid between the radial opening and the passageway to create a first pressure state and a second pressure state in the fluid.

In another aspect of this invention, methods using the novel MWD oil tool components are provided to obtain and transmit desired downhole drilling measurement data to the surface.

DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a drilling assembly.

Figure 2 is a vertical cross-sectional view of a portion of the drilling assembly of Figure 1.

Figures 3 and 3A are schematic views of a turbine assembly of the drilling assembly of Figure 1.

Figure 4 is a exploded perspective view of the turbine assembly of Figure 3.

Figure 5 is a vertical cross-sectional view of the actuator assembly of the drilling assembly of Figure 1.

Figure 6 is an exploded perspective view of the actuator assembly of Figure 5.

Figure 7 is a vertical schematic view of the mud valve assembly of Figure 1.

Figure 8 is an exploded perspective view of a portion of the

mud valve assembly of Figure 7.

Figure 8A is an end view of the inner sleeve of Figure 8.

Figure 9 is a hydraulic diagram of the downhole tool assembly.

Figures 10 and 11 are perspective views of the connectors.

Figure 12 is a cross-sectional view of the connectors when mated together.

Figure 13 is an exploded perspective view of the circuit board assembly.

Figure 14 is a schematic view illustrating connection of the actuator and turbine assemblies.

Figure 15 is a cross-sectional view of an alternate preferred embodiment of a turbine/actuator assembly.

Figure 16 is a cross-sectional view illustrating an alternate embodiment used to prevent vertical movement of the turbine/actuator assembly in a collar.

Figure 17 is a cross-sectional axis taken along line 17-17 of Figure 16.

Figure 18 is a cross-sectional view of an alternate embodiment of the mud valve.

BEST MODE OF CARRYING OUT THE INVENTION The novel components of this invention may be used separately or in combination in a variety of oil well drilling tools. Without intent to limit the scope of this invention their preferred embodiment shall be described when used in a MWD mud pulser. Referring to the drawing wherein like reference characters are used for like parts throughout the several views, a drill string 10 (see Figure 1) is suspended in a wellbore 12 and supported at the surface 14 by a drilling rig 16. The drill string 10 includes a drill pipe 18 coupled to a downhole tool assembly 20. The downhole tool assembly 20 includes multiple (e. g., twenty) drill collars 22, a measurement-while-drilling (MWD) tool assembly 1, a mud motor 24, and a drill bit 26. The drill collars 22 are connected to the drill string 10 on the uphole end of the drill collars 22, and the uphole end of the MWD tool assembly 1 is connected to the downhole end of the drill collars 22. The uphole end of the mud motor 24 is connected to the downhole end of MWD tool assembly 1. The downhole end of the mud motor 24 is connected to drill bit 26.

The drill bit 26 is rotated by the mud motor 24 which responds

to the flow of drilling fluid, or mud, which is pumped from a mud tank 28 through a central passageway of the drill pipe 18, drill collars 22, MWD mud pulser 1 and then to the mud motor 24. The pumped drilling fluid jets out of the drill bit 26 and flows back to the surface through an annular region, or annulus, between the drill string 10 and the wellbore 12. The drilling fluid carries debris away from the drill bit 26 as the drilling fluid flows back to the surface. Shakers and other filters remove the debris from the drilling fluid before the drilling fluid is recirculated downhole.

The drill collars 22 provide a means to control the force of the drill bit 26 against the formations, enabling the drill bit 26 to crush and cut the formations as the mud motor 24 rotates the drill bit 26. As drilling progresses, there is a need to monitor various downhole conditions. To accomplish this, the MWD tool assembly 1 measures and stores downhole parameters and formation characteristics for transmission to the surface using the circulating column of drilling fluid. The downhole information is transmitted to the surface via encoded pressure pulses in the circulating column of drilling fluid.

One common MWD tool assembly is the MWD mud pulser. In general, a MWD mud pulser comprises in operative connection an actuator assembly and a valve assembly. In the preferred embodiment illustrated in Figure 2, from top to bottom, the components housed within the MWD mud pulser 1 include a bull plug 100, an upper rubber fin centralizer 300a, a survey measurement assembly 200, a lower rubber fin centralizer 300b, an interface assembly 400, a turbine assembly 500, an actuator assembly 600 and a valve assembly 700.

The bull plug 100 diverts the drilling fluid and protects the upper end of upper rubber fin centralizer 300a. The rubber fin centralizers 300a and 300b coaxially center the survey measurement assembly 200 and the interface assembly 400 that are housed within non-magnetic drill collar 2.

The survey measurement assembly 200 may include, for example, survey sensors, a microprocessor, microprocessor control program, and such additional supporting electrical circuitry (not shown) for producing electrical signals representative of downhole information that may be of interest. These electrical signals, via the

interface assembly 400, control a spool valve 647 (see Figure 5), within the actuator assembly 600. The spool valve 647 controls the flow of hydraulic fluid to a rotary actuator 657, which in turn, controls a valve sleeve 703. (See Figure 7).

Referring to Figure 7, the valve sleeve 703 may be shifted between positions of low resistance (referred to as the open position) and high resistance (referred to as the closed position, though not totally restricting the flow) to the flow of the drilling fluid. Shifting the valve sleeve 703 from an open position to a closed position and then back to an open position generates a momentary pressure increase, or pressure pulse, which is detectable on the surface with a pressure sensor. Detected pressure pulses may be decoded in order to reconstruct the information of interest. Thus, in response to the electrical signals generated by the survey measurement assembly 200, pressure pulses are generated in the drilling fluid corresponding to the information of interest and the sequence of pressure pulses carries this information which is recoverable at the surface.

Referring to Figures 2 and 6, circuitry within the interface assembly 400 rectifies and regulates the three phase AC output of alternator 625. The regulated power is distributed to the survey measurement assembly 200 and the actuator assembly 600.

Drilling fluid flows through the drill string 10 and past the stabilizer 300a, the survey measurement assembly 200, the stabilizer 300b, the interface assembly 400, and then, into the inlet ports 510 (see Figure 3) of the turbine assembly 500.

Referring to Figure 3, as the drilling fluid flows past the turbine rotors 538 the drilling fluid exerts a force on the turbine rotors 538 which causes a rotation of a drive shaft 539. The drive shaft 539, which is mechanically coupled to the actuator assembly 600, provides mechanical power to drive the alternator 625 and a hydraulic pump 634 (see Figure 5). Electrical power provided by the alternator 625 powers the electrical systems, and hydraulic power provided by the hydraulic pump 634 powers the rotary actuator 657 which opens and closes the valve 700.

More detailed descriptions of components of the MWD mud pulser 1, such as the turbine assembly 500, the actuator assembly 600, the valve assembly 700, the connectors 550 and 608, and the printed circuit board assembly 202, as well as the method for assembling

the MWD mud pulser, are found below in the respective sections.

1. Turbine Assembly Referring to Figures 3 and 4, the turbine assembly 500 is the system prime mover; that is, the turbine provides the rotary power to drive the alternator 625 and the hydraulic pump 634. The turbine assembly 500 is mechanically and electrically coupled and keyed to the actuator assembly 600. Broadly, the turbine assembly 500 includes a stator 536 and a rotor 538 mounted for rotation within the stator 536. Stator 536 is provided with at least one passageway or conduit 557 arranged to receive and permit electrical wires from the connector 518 to pass through the turbine assembly 500 to the connector 550. The passageway may be sealed and may be pressurized. It may extend in substantially a straight line generally parallel to the axis of the turbine assembly 500. The turbine assembly 500 may also include at least one port 512g positioned and constructed to receive fluid and which is communicating with the passageway. The port 512g may include a pressure operated, one-way valve, such as valve core 514 and may be closed by a removable plug 515.

In a preferred embodiment the assembly of the turbine assembly 500 begins with the installation of a feed-through connector 518. Wires are soldered to both ends of feed-through conductors 518a on the connector 518, the two 0-rings 517 are installed in the 0-ring grooves 518b on the body of connector 518, and then the connector 518 is installed in a weldment 512. In the course of installing the connector 518, the wires on the top side of connector 518 are fed from the lower end of the weldment 512 through a hole 512a in the center of weldment 512 up to and through the upper end of weldment 512. The connector 518 is seated in gland 512e, and the wires on the up-hole side are trimmed and soldered to connector 501. The 0-ring 502 is installed on the outside of the connector 501, and the wires are folded and stuffed into the upper end of weldment 512 as the connector 501 is installed in the upper end of weldment 512.

The connector 501 is keyed to the upper end of weldment 512 by set screws 516. The connector 518 is a high pressure, high temperature connector designed to protect connector 501 and the balance of the electronics installed above connector 501.

Connector 518 may be eliminated if connector 501 is designed to withstand the downhole operating conditions. The connector 518 is held in place by the interference between the body of connector 518 and tapered ring 519. The tapered ring 519 is, in turn, held in place by accumulator housing 525.

The interface assembly 400 is connected to the top end of the weldment 512 via threaded nut 506. One of the two 0-rings 511 is installed in 0-ring gland 512c on the upper end of the weldment 512, and nut 506 slipped onto the upper end of the weldment 512b.

The two half-shells 504, which are installed in groove 512f and held together by 0-ring 503, hold the nut 506 in place on the weldment 512. The second of the two 0-rings 511 and 0-ring 505 are installed in conjunction with the installation of the rubber fin centralizer 300b.

The drilling fluid is directed through the turbine assembly 500 via a diverter 510 which slides over the upper end of weldment 512. The diverter 510 is keyed in place with dowel pins 513 and held in place on top of the weldment 512 by a nut 508. The 0-ring 507 is installed in an interior gland of nut 508, and the nut 508 slides over the upper end of weldment 512 and is threadedly attached to the weldment 512. The 0-ring 507 keeps debris out of the threaded area below the 0-ring 507. The drilling fluid may be extremely abrasive and diverter 510 is a disposable part that absorbs the wear caused by the incoming drilling fluid.

The turbine accumulator includes elements 521,522,523,524 and 525. The turbine accumulator provides a means to maintain a net positive pressure, with respect to the hydrostatic pressure of the column of drilling fluid, in the interior cavities of the turbine. The snap ring 520, which is installed in an interior groove of accumulator housing 525, is a means to stop the upward displacement of piston 522. The two 0-rings 524 are installed in the two 0-ring grooves on the lower end of housing 525, and the accumulator housing 525 slides into the cavity within 512 from the lower end.

The wires on the lower side of feed-through connector 518 are fed down through the cavity within the weldment 512 and into cross holes 512c as shown in Figure 4. As housing 525 slides into place the wires running from connector 518 are worked into the grooves 525a running along the outside of 525. The relative alignment of

the grooves 525a and the cross holes 512c is maintained by dowel pins 526 which engage the slots 525b on the accumulator and slots 512d on the weldment. After this assembly has been completed, the wires on the lower side of connector 518 run laterally down to the top of grooves 525a, alongside the accumulator housing in grooves 525a and into the cross holes 512c. The accumulator housing 525 holds tapered ring 519 and connector 518 in place via the interference of the parts. The accumulator housing 525 is, in turn, held in place by the interference between housing 525 and the upper bearing housing 533.

The upper end of shaft 539 is secured by bearing 532 which is seated in upper bearing housing 533. The housing 533 surrounds the bearing 532, disc springs 529 (that go in on top of the bearing 532), the piston 528 and an 0-ring 527. The 0-ring 527 goes in the 0-ring groove on piston 528 and slides into the opening 533b of housing 533. On each side of the housing 533, near the outer edge, are two 0-ring glands 533a. An 0-ring 530 fits in each of these glands 533a. The glands 533a are associated with the passageway 557 that extends through the turbine assembly 500 to provide the means to run wires from connector 518 to connector 550. On the underside of housing 533 is a gland for shaft seal 534. Other shaft seals may be used in this application. Seal 534 is a lip seal which may be encapsulated in a stainless steel housing. Seal 534 is held in place by snap ring 535. The seal 534 seals the passage between the housing 533 and the shaft 539.

Below the upper bearing housing 533 are two turbine stators 536 and two turbine rotors 538. The rotors 538 are keyed to shaft 539 via key 540. The bottom rotor slides over the upper end of shaft 539 and shoulders up on the raised area 539a on shaft 539.

The turbine stack is assembled by sliding the lower rotor 538 onto the shaft 539 from the upper end of the shaft 539 and then sliding the lower stator 536 over the lower rotor 538 from the upper end of shaft 539. Next, the upper rotor 538 slides onto the shaft 539 from the upper end of shaft 539 and is axially fixed in position by a snap ring 537. The rotors are axially positioned on shaft 539 between the raised area on the area 539a on the shaft 539 and the snap ring 537 located in snap ring groove 539b. Then the upper stator 536 slides over the upper rotor 538 from the upper end of shaft 539.

Each rotor 538 has evenly spaced fins 538a that are circumferentially located on the body of the rotor 538. Each stator 536 of the turbine assembly has evenly spaced ports 536a that are circumferentially arranged about the stator 536. The ports 536a form passages through the stator 536 that run axially along the body of the stator 536 while the passages through the rotor fins 538a are defined as"cupped"blades. In traditional turbine design, the fins on both the rotor and stator are"cupped," and more specifically, they are"cupped"in the opposite direction.

The rotors and stators of the traditional design are manufactured in a casting process which is burdened by large financial investment in the castings. Unlike traditional designs, by making the ports 536a through the stator straight while maintaining a "cupped"profile for the rotor blades, the rotor and stator can both be manufactured in small volume at a significantly reduced cost.

Below the lower turbine stator is a seal plate 541. On the underside of the seal plate 541 is a gland for shaft seal 542. The seal 542 is a lip seal which may be encapsulated in a stainless steel housing. The seal 542 is held in place by snap ring 543.

The seal 542 seals the passage between the seal plate 541 and the shaft 539. The 0-ring 544 seal is one of several seals that is employed to seal the internal cavity of the turbine assembly 500.

Seal plate 541 is also provided with 0-ring glands 541a through which passageway 541a extends and is alignable with passageway 557 to provide the means to run wires from connector 518 to connector 550.

The lower weldment 546 features a means to secure the lower end of shaft 539, porting through the weldment 546 for wireways, means to key the turbine assembly to the pulser collar 4, and means to couple, electrically and mechanically, the turbine assembly 500 and the actuator assembly 600. The porting through weldment 546 is through passageway 546c which extend axially down to intersect a diagonally drilled passageway 546d, shown in Figure 3, which extends axially downwardly and radially inwardly to intersect drilled passageway 546e. Drilled passageway 546e extends from the intersection with passageway 546d to the lower end of the weldment 546. The weldment 546 is made up of two pieces to form the diagonal hole through the part.

The turbine assembly components, upper weldment 512, bearing housing 533, two stators 536, seal plate 541 and lower weldment 546 are held together by the cap screws 549. An advantage of this segmented assembly is that the bolts hold the assembly together so the assembly can be removed as a unit. The drilled passageways through the components are aligned with respect to one another and wires are fished through the wireways. As the components are brought together the upper end of shaft 539 engages seal 534 and bearing 532. Seal plate 541 and lower weldment 546 slide over the lower end of shaft 539, and seal 542 and bearing 545 engage the shaft 539 just below the raised area 539a. The bolts 549 hold together the upper weldment 512, lower weldment 546 and all of the intervening components. The bolts 549 go through the lower weldment 546 and through the seal plate 541, the two stators 536 and the upper bearing housing 533, and the bolts 549 are threadedly anchored in the upper weldment 512.

The wires, which are pulled through the passageways in the course of assembling the turbine assembly, are cut to length and soldered to the terminals 550a on the connector 550. The connector 550 is attached to the lower end of weldment 546 with bolts 551, and the excess wire is folded over into pockets 546f of the lower weldment 546 and potting material or lacing cord is used to secure the wires in the pockets 546f.

Referring to Figure 3A, the sleeve 552 provides the means to mechanically attach the turbine assembly 600 to the actuator assembly 500.0-ring 547 is installed and sleeve 552 is slipped over the lower end of the weldment 546. The sleeve 552 is held in place by balls 554. A passage 550j along the side of connector 550 and a passage 546g along the lower end of the weldment 546 provides the means to load the balls 554 in the cavity formed by inner ball race 546h and outer ball race 552a. To load the balls, the turbine assembly is turned upside down and tilted slightly. The balls are dropped through the passages 550j and 546g, and the balls fall through the passages 550j and 546g into the cavity formed by inner ball race 546h and outer ball race 552a. The balls are held in place by a keeper 555 which is inserted into the passages 550j and 546g. Keeper 555 is in turn held in place by a screw 556.0-ring 553 is installed in an interior gland on sleeve 552 and provides a means to seal the passage between the threaded end of the sleeve

552 and the upper, threaded end of pressure housing 664.

The turbine assembly 500 includes a passageway through which electrical wires extend from connector 501 to connector 550. This passageway extends from the upper end of weldment 512 down through the center of weldment 512, along the outside of housing 525 in the cavity formed by groove 525a, through the diagonally drilled passageway 512c, through each of the passageways 533c, 536a, 536b, 541a, 546c, 546d, 546 and 546a, and 546i.

The electrical wiring through the turbine assembly provides the means to power the electronics located above the turbine assembly 500 with the alternator 625 which is located below the turbine assembly 500 in the actuator assembly 600. The electrical wiring through the turbine assembly 500 also provides the means to control the power to the solenoids within the spool valve 647. The spool valve 647 in turn controls the position, either open or closed, of the assembly valve 700.

Referring to Figure 2, pulser collar 4 is provided with an inner annular shelf or shoulder 4a having an upper surface on which lower weldment 546 rests. Thus turbine assembly 500, as well as actuator assembly 600 and valve assembly 700 are supported with pulser collar 4 by shoulder 4a. To prevent vertical movement and to retain the supported components in a fixed location, pulser collar 4 is provided with valve collar 5 as explained in more detail below. To key the turbine assembly 500 within the pulser collar 4, the dowel pins 548 of the lower weldment 546 are configured to align with mating ports 4c (see Figure 2) that are formed in the shelf 4a.

An alternative embodiment of the combined turbine and actuator assemblies is depicted in Figure 15. In this embodiment, lower end of the turbine assembly 500'is adapted to provide the means to directly couple alternator 625 to lower weldment 546'. This embodiment eliminates any need for connectors 550 and 608 as well as items 602-607 and 609-619 shown in Figures 3-6 and Figures 10- 11. Alternator coupling 623 is replaced by an alternatively constructed coupling 623'. In the course of attaching the alternator 625 to lower weldment 546', the splined end (external spline) of shaft 539'engages the splined (internal spline) end of coupling 623'. This embodiment provides for the replacement of the turbine accumulator elements 521-525 and the actuator accumulator

667 with a bladder assembly 560, whose housing 560a replaces the flow diverter 510 of the Figures 3-4 design.

In this alternative embodiment of the turbine assembly 500', the upper end weldment 512 is replaced by upper turbine end 512' and the bladder assembly 560 comprising bladder housing 560a and bladder 560b. The bladder 560b, which is made of a non-permeable elastomer such as buna or viton, is retained on housing 560a with lacing cord 561 to form an annular cavity 570 between bladder housing wall 560c and bladder 560b. Bladder housing 560a is provided with an upper and lower annular raised lip 560d and 560e positioned to situate lacing cord 561 between one of the upper or lower raised lips 560d or 560e and a corresponding raised annular upper or lower flange 560f and 560g, respectively of bladder housing 560a. In this embodiment, lacing cord 561 is fixed in position to maintain bladder 560b in sealing contact with bladder housing 560a. Bladder housing 560a is sized to provide for an annular space 575 between the inside wall surface of collar 4'and the outside wall surface of bladder 560b. Bladder housing passageways 572a, 572b and 572c connect annular cavity 570 to wire passageway 562 to provide for hydraulic communication between annular cavity 570 and the other fluid internal chamber of the combined turbine assembly 500'and actuator assembly 600'. Bladder 560b is sized and constructed of an elastomer which accommodates any changes in fluid volume resulting from the contraction or expansion of the fluids to include trapped air inside the turbine assembly 500'or actuator assembly 600'. The entire turbine assembly 500'is held together with cap screws 549 which are threadingly secured in bladder housing 560a.

Referring now to Figures 16 and 17, ports 571 positioned at the base of the bladder housing 560a also provide for hydraulic balance between the annular cavity 570 and annular space 575.

Features incorporated into upper turbine end 512'provides the electrical and mechanical means to connect interface assembly 400 to the turbine assembly 500'. Turbine assembly 500'features an alternative embodiment in which the upper turbine end 512' incorporates a means to electrically and mechanically attach an additional finned centralizer 300a to the upper end of the turbine assembly 500'. The upper end of this finned centralizer in turn provides the means to electrically and mechanically connect the

interface assembly 400 to the turbine assembly 500'.

The assembly of turbine assembly 500'begins with the installation of connector 501'. Wires 559 of a suitable length are soldered to the connector 501', 0-ring 502 is installed on connector 501 and connector 502 is slid into position within connector bracket 563. As described previously, a passageway 562 extending from connector 501'through lower weldment 546', is made up of inner-connecting passageways 562a-562e which flow through the various components comprising the turbine assembly 500'. The remaining construction and method of assembly is substantially similar to that described with respect to the Figures 3-4 design. In the last phase of the assembly of turbine assembly 500', the bladder housing 560a is secured to the balance of the turbine assembly with cap screws 558.

2. Actuator Assembly The actuator assembly 600 provides hydraulic power to operate the mud valve and also provides electrical power to the electronics. Actuator assembly 600 connects to the turbine assembly 500 which provides the rotary power to drive the alternator 625 and the hydraulic pump 634. In general, the hydraulic system forming part of actuator assembly 600 comprises an accumulator 667 and a pressure operated, one way inlet valve, such as valve core 606. The accumulator is structured to maintain the fluid pressure in its reservoir, and the valve is arranged to allow hydraulic fluid to be added, under pressure, to the reservoir.

Referring to Figures 5 and 6, a preferred sub-assembly of the actuator assembly 600 includes components 602 through 619 that provide a means to seal the upper end of actuator assembly 600 within pressure housing 664. This sub-assembly also provides the means to electrically connect alternator 625 and spool valve 647 to connector 550 on the lower end of turbine 500 and to mechanically couple alternator 625 and hydraulic pump 634 to drive shaft 539 of turbine assembly 500.

The bearing 603 is installed in the top of connector 608 and held in place by a snap ring 602. An 0-ring 609 and a dowel pin 610 are installed in the lower end of the connector 608 and the non-rotating portion of the face seal 612 is inserted in the lower

end of the connector 608. The 0-ring 609 seals the passage between the connector and the non-rotating portion of the face seal 612.

The rotating portion of the face seal 612 slides over the upper end of shaft 615 and is held in place by set screws (not shown). The 0-ring 613 within the face seal 612 seals the passage between the face seal 612 and the shaft 615. Lower bearing 617 slides over the lower end of shaft 615, and shaft 615 is held in place via the opposed bearing 603 by securing bracket 619 to connector 608 with cap screws 604. Cap screws 604 run through the 0-rings 607 and are anchored in threaded holes 619a in bracket 619.0-rings 607 seal the passage between cap screws 604 and connector 609.

The coupling 601 provides the means to couple shaft 615 to turbine shaft 539. The coupling 601 is threadedly attached to the upper end of shaft 615. In the course of attaching the turbine assembly 500 to the actuator assembly 600, the splined (external spline) end of shaft 539 engages the splined (internal spline) end of coupling 601.

The coupling 623, keys 616 and 624, and set screws 622 provide the means to couple shaft 615 to alternator shaft 625a. Coupling 623 is installed on shaft 615 and bracket 619 is secured to alternator 625 with cap screws 621 and washers 620. Set screws 622 secure the coupling 623 to shaft 615 and alternator shaft 625a.

Bracket 628, keys 626 and 633, and coupling 631 provide the means to couple hydraulic pump 634 to the alternator 625. The coupling 631 is secured to the shaft 625b via set screws 632 installed in the upper end of coupling 631, and bracket 628 is attached to the lower end of alternator 625 by means of cap screws 629. Set screws 632 installed in the lower end of coupling 631 secure coupling 631 to the shaft of the hydraulic pump 634.

The bracket 639 provides the means to secure the hydraulic pump 634 to spool valve 647. The bracket 639 also houses a relief valve 641 and strainer 637. The 0-ring 638 and strainer 637 are installed in port 639a and secured in place with snap ring 636.

0-ring 640 is installed on the relief valve 641, and the relief valve 641 is installed in bracket 639 from the lower end of the bracket 639. The relief valve is held in place by washer 642 and snap ring 643. The port through which the relief is installed is sealed off by plug 645 and 0-ring 644. Port 639c is sealed with an expanded plug 665. The bracket 628, pump 634, bracket 639 and

spool valve 647 are held together by cap screws 630.0-rings 635 and 646 are installed along the high pressure conduits through bracket 639 and spool valve 647 to maintain the integrity of the fluid flow to the spool valve.

An accumulator 667 is formed from 0-rings 648, piston 649, disc springs 650 and a bracket 652. The accumulator provides the means to store within the actuator assembly 600 a small reserve volume of fluid and to offset the hydrostatic pressure due to the column of fluid in the drill string 10.0-rings 648 are install on piston 649, and the disc springs 650 and piston 649 are inserted in bracket 652. Grooves 652a in the upper end of bracket 652 provide the means for hydraulic communications across the end of the bracket 652.

The rotary actuator 657 and bracket 652 are secured to spool valve 647 with cap screws 660. Plug 655 and 0-rings 651,653,654 and 656 are installed in the course of attaching bracket 652 and rotary actuator 657 to spool valve 647.0-rings 651 and 656 seal the fluid paths between the spool valve 647 and rotary actuator 657.0-ring 653 seals the passage between bracket 652 and plug 655, and 0-ring 654 seals the passage between rotary actuator 657 and plug 655.

0-rings 658 and 659 are installed on the lower end of rotary actuator 657, and lug 663 is threaded onto the lower end of rotary actuator 657.0-rings 658 and 659 seal the passage between the lug 663 and rotary actuator 657.

0-rings 614 and 662 are installed in conjunction with the installation of the pressure housing 664. In general the method for implementation of the hydraulic system includes submerging the hydraulic system in a tank of hydraulic fluid, applying a vacuum to the fluid to remove air from the hydraulic system, releasing the vacuum and mounting the pressure housing over the hydraulic system while the system remains submerged. Once the system is charged, it can then be assembled with other components, such as turbine assembly 500.

In the preferred embodiment, the actuator assembly 600, less the pressure housing 664, is placed in a horizontal tank filled with hydraulic fluid. Via the coupling 601, the alternator 625 and hydraulic pump 634 are rotationally driven in order to functionally check the system and to chase the air out of the hydraulic system.

After removing the air from the hydraulic lines in the assembly, the assembly is removed from the horizontal tank and lowered into a vertical tank filled with hydraulic fluid and the tank is sealed.

A vacuum is pulled on the tank in an effort to remove any additional trapped air. A predetermined vacuum level (e. g., a 28 inch vacuum) is held on the tank for a predetermined duration (e. g., 15 to 20 minutes), and then the vacuum is released. With the actuator assembly remaining submerged in the vertical tank, the pressure housing 664 is slipped over the actuator assembly and threaded onto lug 663. The actuator assembly 600 is then removed from the vertical tank and the valve core 606 is installed.

The accumulator 667 is charged with hydraulic fluid in the final stages of preparing the tool for use. Externally, a hydraulic pump is attached to the connector 608 via a port 608k, and hydraulic fluid is pumped into the system, charging the system to a nominal pressure of, for example, 250 psi. In the process of charging the system, piston 649 is moved downwardly compressing springs 650. After charging the actuator assembly 600, the charging apparatus is removed, and valve core 606 checks the back flow of hydraulic fluid. Plug 605 is installed in connector 608 to provide an added degree of security. The top of plug 605 is flush with the surface so that it does not interfere with the make up of the connectors 608 and 550.

A hole through the shaft 657a of rotary actuator 657 and through plug 655 provides the means to check the charge on the accumulator, as well as the means to communicate the hydrostatic pressure due to the drilling fluid to the interior of bracket 652.

A rod inserted through shaft 657 facilitates a measurement of the location of piston 649 with respect to an external reference such as, for example, the lower end of lug 663. With regard to the second function, hydraulic communication between the drilling fluid on the outside of the actuator assembly 600 and the hydraulic fluid on the inside of the actuator assembly 600 provides the means to limit the pressure across the rotary actuator shaft seal (not shown) and the 0-ring seals 607,609,613,614,658,659,661 and 662 to a pressure which is no greater than the accumulator charge.

That balance is established by movement of piston 649. Thus, a method for use of a hydraulic system is disclosed utilizing an accumulator having a reservoir filled with hydraulic fluid and a

piston having a position indicative of a pressure level of the hydraulic fluid. The method includes determining the position of the piston, and based on the position, determining the pressure level of the hydraulic fluid.

Four grooves on brackets 652 and 639 are bolt passageways.

This grooved structure reduces the need for deep hole drilling, thus enhancing the manufacturing process.

The slots 647a and 639b form a flow path for the circulating hydraulics fluid and a wire conduit for the wires that connect the solenoids of valve 647 to the connector 608.

Wires extend from spool valve 647 to the connector 508 and extend from the alternator 625 to the connector 508. To take out slack in the wires, the wires run alongside of the bracket 619 and are folded into the pocket 619b and held in place by 0-rings 618 or lacing cord (not shown). Similarly, wires that run alongside of the bracket 628 are held in place by 0-rings 627 or lacing cord.

Referring again to Figures 15-17, an alternate embodiment of actuator assembly 600'is illustrated. The assembly of the alternator 625, pump 634, bracket 639, and spool valve 647 is as described above. Since the actuator accumulator 667 is removed in this embodiment, the rotary actuator 657'is directly secured to spool valve 647 with cap screws 668.0-ring 669 seals the passage between rotary actuator 657'and plug 670'. The fluid paths between rotary actuator 657'and spool valve 647 are sealed via O- rings 671. In this embodiment the threaded nose of rotary actuator 657 as shown in Figures 5-6 is replaced by a cylindrical nose 672 adapted to receive 0-rings 673. Corresponding change to lug 663 give rise to lower lug 663'having a cylindrical bore 674.0-rings 675 seal the passageway between the nose of rotary actuator 657' and the internal bore 674 of lower lug 663'. This arrangement provides for a means to install the lug 663'as the last step in the process of assembling the turbine assembly 500'to actuator assembly 600'.

After the actuator components have been assembled and attached to the lower end of weldment 546'the wires 559, which run from connector 501'through turbine passageway 562 within the turbine assembly 500'and out the lower end of weldment 564', are connected to alternator 625 and spool valve 647. Pressure housing 664' (shown having two female threaded ends) is then slipped over the

lower end of the actuator assembly 600'and threadingly attached to weldment 564'. The connected turbine and actuator assemblies are turned upside down, evacuated, filled with hydraulic fluid and the lug 663'is threaded onto the lower end of pressure housing 664'.

3. The Valve Assembly Referring to Figures 7 and 8, the lower end of a lug 663 receives the outer sleeve 701 of a mud valve 700. The inner sleeve 703 is attached to an actuator coupling 702 with hex head bolts 705 which are secured in threaded holes 702b by lock washer 704. The splined coupling 702 engages the splined end 657a of actuator shaft 657 and provides the means to roughly align the flow slots 703b of the inner sleeve with the flow slots 701a of the outer sleeve.

Slots 703a (see Figure 8A), in the upper end of inner sleeve 703 provide the means for a precise alignment of slots 703b of the inner sleeve with respect to the slot 701a of the outer sleeve.

As a matter of practice, the adjustment of the inner sleeve 703 with respect to the outer sleeve 701 takes place after outer sleeve 701 has been made up to the actuator assembly 600 and the turbine assembly 500 and actuator assembly 600 have been coupled together and installed in the pulser collar 4. After this adjustment has been completed, then valve collar 5 is made up to pulser collar 4.

Valve collar 5 is provided with an inner, annular shelf as shoulder 5a having a lower surface 5b preferably shaped to permit nut 707 to seat on surface 5b when it is threaded onto outer sleeve 701.

The inner valve sleeve 703 and spacer sleeve 706 are held inside 701 by nut 707. Spacer sleeve 706 maintains the axial alignment of inner sleeve slots 703b with respect to the outer sleeve slots 701a. The nut 707 also retains the pulser assembly within pulser collar 304 and in conjunction with shoulder section 4a prevents vertical movement of the connected assemblies. Set screws 708 are installed in threaded holes 707a and pulled down against the end 701b of outer sleeve 701. The set screws 708 prevent nut 707 from backing off while tool assembly 1 is in service. The use of a single collar having two co-operating inner extending shoulder sections, or two collars, such as pulser collar 4 and valve collar 5 to support and retain an oil tool in a fixed position within a pipe is one feature of this invention.

Figure 7 is a section view of the mud valve. The primary components of the mud valve assembly are outer sleeve 701, inner sleeve 703, and valve collar 5. Drilling fluid flow proceeds downstream from the turbine assembly 500 through the annular passage between the outer wall of the actuator assembly 600 and the inner wall of the pulser collar 4. With slots 701a and 703b aligned, the drilling fluid flows radially inwardly, as indicated by the arrow C in Figure 7, into the central axial flow passage 709 and down through the internal passage 709 within 5 to the mud motor and out the bit.

Mud flow through the turbine assembly 500 provides rotary power to drive the actuator assembly 600, and in turn, the actuator assembly 600 provide the means to rotate the shaft 657a of rotary actuator 657. Rotation of shaft 657a causes the inner sleeve 703 of valve assembly 700 to rotate the small openings 703c of inner sleeve into alignment with slots 701a of the outer sleeve. This valve position is referred to as the closed valve position. In the closed position, the flow area through the valve is decreased, and thus, the pressure drop across the valve is increased. The actuator assembly 600 also provides the means to rotate the inner sleeve back to the original position, which is referred to as the open valve position, where inner sleeve slots 701a are aligned with the outer sleeve slots 703b.

Figure 18 depicts an alternate embodiment of the mud valve.

The inner valve sleeve 703 and spacer sleeve 706, which are described with reference to Figures 7-8, are respectively replaced by inner valve sleeve 703'and spacer 706'. The first principal differences between inner valve sleeves 703 and 703'are the slots in inner valve sleeve 703 consist of axial slots 703b and circumferential slots 703c (See Figure 8) whereas inner valve sleeve 703'incorporates only axial slots 703b'. The second principal difference is the outside diameter of 703'is only slightly less than the inside diameter of outer sleeve 701 whereas outer sleeve 703'provides for substantial clearance (of the order of 0.1") between the inner valve sleeve 703'and the outer valve sleeve 701. The difference between spacers 706 and 706'is the upper end of spacer 706 is turned down and the upper end of spacer 706'is slotted. In this embodiment, when the valve is in the "open position", the flow path is substantially the same as that

described above. In the"closed position"there is a significant distinction in the fluid flow paths associated with the two embodiments. In Figures 7 and 8 embodiment, the flow path is through slot 701a and circumferential slot 703c. In the Figure 18 embodiment, the flow path is through slot 701a, circumferentially around to slot 703b'and then through slot 703b', as well as through slot 701a, axially along a path to slot 706a'and then through slot 706a'. This embodiment is much more tolerant of lost circulation material.

A microprocessor within instrument package 200 makes measurements of parameters of interest and encodes those measurements as a sequence of valve positions. The mud valve may be closed and subsequently opened after, for example, one second to create a pressure pulse which is transmitted through the continuous column of drilling fluid within the drill string. The sequence of valve positions, and thus, the pressure pulses, is correlated to the encoded measurements. At the surface the pressure pulses may be detected and decoded to obtain the measured values of the parameters of interest.

Referring to Figure 9, the hydraulics equipment incorporated into the actuator assembly 600 provides the means to operate mud valve 700. The prime mover PM, which in this case is the turbine assembly 500, drives hydraulic pump 634. Fluid leaving the pump 634 flows to the spool valve 647 or the relief valve 641. Spool valve 647 is a four-way, three position tandem valve. With neither solenoid actuated, the spool is centered with P ported to T. With solenoid 647b actuated, the spool is shifted to connect P to A and B to T. In this configuration, fluid flows from the hydraulic pump 634 through the spool valve 647 to the A port of the rotary actuator 657 and thus, shifts the position of rotary actuator 657.

As the rotary actuator 657 reaches the rotational extreme, the fluid flow to A ceases, line pressure builds, the relief valve opens at a predetermined pressure (i. e., 600 psi), and fluid flows across relief valve 641. As the vanes within the rotary actuator 657 shift positions, fluid flows out of the B port to T and back to the inlet of the pump through strainer 637. With solenoid 647c actuated, the spool is shifted to connect P to B and A to T. Fluid flows from hydraulic pump 634 to the B port of the rotary actuator 657 and shifts the rotary actuator 657 in the opposite direction.

As the rotary actuator 657 reaches the rotational extreme, the fluid flow to B ceases and fluid flows across relief valve 641.

As fluid flows into port B, fluid flows out of port A to T and back to the inlet of hydraulic pump 634 through strainer 637.

Accumulator 664 or bladder assembly 500 provides the means to maintain a small net pressure, with respect to hydrostatic pressure of the column of drilling fluid, on the actuator assembly 600. The pressure compensation afforded by the accumulator provides an assurance that the pressure across the 0-ring seals 607,609,613, 614,658,659,661 and 662 and the shaft seals (not shown) within rotary actuator 657 do not exceed the initial charge pressure of the accumulator. Hydraulic fluid stored within the accumulator 667 serves as a small reserve volume of fluid to compensate for small fluid losses across the seals, particularly the face seal 612.

4. The Connector Assembly Referring to Figures 10,11 and 12, the connectors 550 and 608 are configured to align with each other along a common central axis in order to establish electrical continuity across the connectors and to mechanically interlock the connectors. The mechanical connection restricts rotation of the connectors 550 and 608 about the common central axis with respect to each other and keeps the connectors engaged to each other. The connectors 550 and 608 provide the means to electrically connect the turbine assembly 500 to the actuator assembly 600.

Connectors 500 and 608 each have a similar design, with the differences pointed out below. Connector 550 has an annular body 550a with a central passageway 550d through which the rotary drive of the alternator and hydraulic pump passes. The central passageway 500d is coaxial with the central axis of the body 550a.

The interlocking connection between the connectors is formed from mating surfaces of the connectors. The body 550a of connector 550 has a raised, annular ridge 550n that partially extends around the central passageway 550d at the end of the body 550a. The ridge 550n forms an interlocking"clam shell"connection with a corresponding ridge 608n of connector 608 when the two connectors are mated. The end of the connector 550 has a bullet nose 550c which surrounds the central passageway 550d of connector 550. The bullet nose 550c is configured to engage annular passage 608d of

connector 608. In this manner, the two ridges interlock with each other to prevent the connectors from rotating, one with respect to the other. The bodies of the connectors are locked together so as to minimize the relative motion of the connectors. In turn this minimizes the static and vibrational loading at the pin and socket interconnects.

The ridge 608n has embedded electrical sockets 608g that are configured to mate with corresponding pins 550e that protrude from body 550a near the end of the connector 550. The pins 550e are parallel to the central axis of the body 550a and extend from a portion of the end that receives the ridge 608n.

The pins, 550e and 608e, and the sockets, 608g and 550g, provide the means to electrically connect wires 550i of the turbine assembly and wires 608i of the actuator assembly. To accomplish this, the connector 608 has internal conductive rods 608h that are embedded in the body 608a and extend longitudinally from end to end of the body 608a. The conductive rods 608h are eccentric to the central passageway 608d and are mechanically secured and electrically isolated from the body 608a by an outer, insulative glass seal 608f. The sockets 608g are mechanically supported by a nylon sleeve 608p. Small drilled holes in the opposite end of each of conductive rods 608h provide the means to mechanically and electrically secure wires 608i to conductive rods 608h. The wires 608i are soldered to conductive rods 608h via the drilled holes in the end of the rods.

Similar to connector 608, connector 550 has internal conductive rods 550h that are embedded in the body 550a and extend longitudinally from end to end of the body 550a. The conductive rods 550h are eccentric to the central passageway 550d and are mechanically secured and electrically isolated from the body 550a by an insulative glass seal 550f. Near the mating end of the body 550a, pins 550e are extensions of the conductive rods 550h and are adapted to mate with the sockets 608g. Near the other end of the body 550a, conductive rods 550h extend beyond the body 550a. Small drilled holes in the ends of conductive rods 550h provide the means to mechanically and electrically secure wires 550i to conductive rods 550h. The wires 550i are soldered to conductive rods 550h via the drilled holes in end of the rods.

The connector 550 also has sockets 550g that are configured

to mate with corresponding pins 608e of the connector 608. The pin and socket features of the one connector parallel the pin and socket features of the other.

Among the other features of the connectors, the body 550a of the connector 550 has four holes 550m that permit the bolts to pass through the body 550a. The holes 550m are parallel and eccentric to the central passageway 550d of the body 550a. The holes 550m are aligned with corresponding threaded holes 546j of the lower weldment 546 (see Figure 3). The body 550a also has a keyway 550j that is exposed on the outside of the body 550 and extends along the longitudinal length of the body 550. The keyway 550j, along with a corresponding keyway 546g in the lower end of weldment 546, forms a passageway for loading balls 554. Threaded hole 550k provides a means to secure the ball keeper 555 with the screw 556.

The body 608a of connector 608 has four holes 608j that permit bolts to pass through body 608a. The holes 608j are parallel and eccentric to the central passageway 608d of the body 608a. The holes 608j are aligned with corresponding threaded holes 619a in bracket 619 (see Figure 9). The 0-ring glands within holes 608j provide the means to seal the passage between the bolts and the connector body 608. The ports 608k and 608q are connected by a hole drilled through the body 608. Both ports are threaded to receive pipe fittings such as a pipe nipple or a pipe plug. Pipe plug 605 (see Figure 6) is installed in the port 608k after the actuator assembly has been charged. Within the drilled hole connecting the two ports, 608k and 608q, is a gland 608r designed to seal the port by threadedly securing valve core 606 (see Figure 6) in the port.

The valve core 606 and seat may be tested by threadedly attaching port 608q of connector 608 to a hydraulic test stand.

In some embodiments, the bodies 550a and 608a of the connectors are made of metal and in other embodiments, the bodies 550a and 608a are made of an insulative material, such as PEEK.

In the embodiments where PEEK is used, the conductive rods passing through the body of the connector are sealed directly to the body of the connector. Thus, the need for the glass seals is eliminated.

5. The Printed Circuit Board Assembly The novel circuit board mounting assembly comprises a circuit board mounting body having a mounting surface for receiving the circuit board and a clamping device adapted to engage portions of the circuit board not containing the printed circuit, preferably at least a portion of which shall be the peripheral edges of the circuit board, and most preferably a substantial portion of the peripheral edges, to clamp the circuit board to the mounting surface. One preferred embodiment of the circuit board of this invention is illustrated. In Figure 13 a printed circuit board mounting assembly 202 is adapted to mount a printed circuit board 218 on the upper surface of a section 214 of a chassis 204. The chassis 204 includes two sets of upstanding quarter circular sections 206 which define between them a region 214 for receiving the printed circuit board 218. Preferably, region 214 will be generally flat to match the bottom surface of circuit board 218.

A plurality of upstanding guides 210 extend from the four corners of the region 214 to guide the printed circuit board into position on the surface 214. In addition, a plurality of screw holes 208 are adapted to receive screws (not shown).

If traces on printed circuit board 218 directly contact region 214, the cover 226, or any other part of the mounting assembly 202, then a pair of electrical insulators 220a and 220b sandwich printed circuit board 218. The lower insulator 220b may be a continuous sheet of insulating material which is easy to manufacture to the desired shape. One such material would be the same insulating material from which circuit boards are conventionally constructed.

It is also possible to use materials, such as Teflons, although they have proven to be more difficult to manufacture, with a plurality of apertures 222b alignable with apertures 216 in printed circuit board 218. Similarly, the insulator 220a includes apertures 222a which mate with the apertures 222b and 218 in the insulator 220b and the printed circuit board 218, respectively.

Insulators 222a and 222b include openings 224a and 224b to accommodate any electrical components which extend outwardly from the surface of the printed circuit board 218. A semicircular cover 226 includes a plurality of screw holes 230 which mate with the holes 208 in surface 214. In addition, an opening 228 is provided to permit electrical wires to feed between the elements 206 and

onto the printed circuit board 216.

When the assembly 202 is made up, the elements 220a, 218, and 220b are sandwiched on top of the surface 214 held in alignment by the upstanding pins 210. The whole assembly is sandwiched onto the surface 214 by the cover 226 which is threadedly connected by screws (not shown) to the surface 214. In this way, the printed circuit board 218 is uniformly clamped around its peripheral edge to the chassis 204. This peripheral clamping of the printed circuit board 218 serves to shift the mechanical modes of vibration of the printed circuit board and the components attached to the board to a higher frequency, into a frequency range where the energy available to excite the resonant modes of the printed circuit board and components is substantially reduced. Thus, the clamping of the printed circuit board reduces the effect of mechanical vibration which otherwise causes damage to the printed circuit board, solder joints and electrical components attached to the printed circuit board. Clamping the printed circuit board 216 serves to increase the useful life of the printed circuit board 216 and the components mounted thereon. Although clamping along the peripheral edges of the circuit board is a preferred embodiment, this invention contemplates clamping at other sections of the circuit board free from the electrical components and wire traces.

The object is to minimize the mechanical vibration and to avoid high local stresses that are associated with securing the printed circuit board along the edge at a few places with for example, screws and threaded holes. This is achieved by uniformly clamping the printed circuit board around the periphery.

6. Assembly of the MWD Mud Pulser As stated above, the turbine assembly 500 and actuator assembly 600 are designed to couple together mechanically and electrically. Referring to Figure 14, as turbine assembly 500 is coupled to actuator assembly 600 the splined end of shaft 539 first engages the matching splined coupling 601. Then, the connector 550 on the lower end of turbine assembly 500 engages the connector 608 on the upper end of actuator assembly 600. As connector sleeve 552 is threaded onto the pressure housing the two connectors, 550 and 608, are pulled together, and the pins 550e (608e) engage the sockets of 608g (550g). Continuing to thread connector sleeve 552

onto the pressure housing, the nose 550d of connector 550 engages the opening 608d of connector 608.

Referring to Figures 3 and 4, to charge the turbine assembly 500 with hydraulic fluid, the assembly 500 is placed in a vertical position and filled with hydraulic fluid via port 514a of the upper weldment 512. As hydraulic fluid is introduced into the system, the fluid displaces air trapped inside the assembly 500. This displaced air exits the assembly 500 through another port 514a (not shown) in the upper weldment 512. Once the air is substantially displaced, as evidenced by a flow of hydraulic fluid, a valve core 514 (e. g., a Shrader valve core) is installed in each of the ports 514a of the upper weldment 512. A plug 515 is then installed in one of the ports 514a above the valve core 514, and the hydraulic charging tool is attached to the other port 514a to charge the accumulator in the assembly 500 to a predetermined pressure (e. g., 100 p. s. i.). The charging tool is then removed from the port 514a, and a plug 515 is then installed in this port 514a to seal the assembly 500.

The assembly, including the interface assembly 400, turbine assembly 500, actuator assembly 600 and outer valve sleeve 701 which is threadedly attached to the lower end of lug 663, are installed in pulser collar 4. The entire assembly slides into pulser collar 4 and the dowel pins 548 of the turbine assembly 500 are made to engage the mating ports 4c that are formed in the shelf 4a. Besides holding the turbine assembly 500, the shelf 4a also prevents the bolts 549 of the assembly 500 from backing out. Per the alignment procedure discussed above, the inner valve 703 is inserted through the open end of outer valve sleeve 701 and the inner valve 703 is aligned with respect to the outer sleeve 701.

The valve collar 5 slides over the outer valve sleeve 701 on the lower end of the assembly, and the valve collar 5 is threadedly attached to the lower end of pulser collar 4. The inner valve sleeve 703, spacer sleeve 706 and the entire pulser assembly are secured by a nut 707, which is made up to the lower end of outer valve sleeve 701. The set screws 708 prevent nut 707 from backing off while the MWD tool assembly 1 is in service.

Referring to Figure 16, an alternative embodiment is disclosed for securing and retaining the turbine assembly 500'and connected actuator assembly 600'within collar 4'in a fixed position.

Collar 4'is provided with an annular inner shelf or shoulder 4a' sized to permit lower weldment 546'to sit on shoulder 4a'with actuator assembly 600'extending below shoulder 4a'. Dowel pins 548 are provided as described with reference to the Figure 2 embodiment to prevent turbine assembly 500'from rotating on shoulder 4a'. Positioned on the upper surface of bladder housing 560a is a force loading assembly to exert a downhole directed load to turbine assembly 500'. In a preferred embodiment, the force loading assembly comprises disc springs 574 which axially load bladder housing 560a when the lower end 3a'of collar 3'presses against spacer 573 when collar 3'is threadedly attached to collar 3'. This embodiment permits substantially greater loads to be asserted against bladder housing 560a to hold or fix the turbine assembly 500'against shoulder 4a', than can be applied by nut 707 in the Figure 7 embodiment.

The assembly of the MWD tool assembly 1 is continued by attaching bull plug 110, rubber fin centralizer 300a, survey measurement assembly 200 and rubber fin centralizer 300b to the upper end of the pulser assembly (which is the upper end of the interface assembly 400). The cross-over sub 3 and the non-magnetic drill collar 2 slide over the upper end of pulser assembly and are threadedly attached to the upper end of pulser collar 4.

Other embodiments of the invention would be obvious from the teachings and disclosures above and such embodiments are within the scope of the invention, as defined by the following claims.