Abstract:
The pump assembly comprises means defining a fluid retention chamber having an inlet opening and an outlet opening therein, and check valve means adjacent the inlet and outlet openings, which are operative to limit the fluid flow therethrough to relatively inward and outward of the chamber, respectively, when there is a fluid pressure differential thereacross. The pump assembly also comprises hollow pulse generating means in the chamber, having a volume of less than that of the chamber, but including a normally contracted, resiliently flexible portion which is responsive to a fluid pressure pulse in the hollow of the pulse generating means, to flex in relation to the normally contracted condition thereof. It also comprises inpulsing means which are operative to impart a fluid pressure pulse to the hollow of the pulse generating means, to cause the flexible portion of the pulse generating means to flex and impart a fluid pressure output pulse to a fluid medium retained in the chamber.

Description:
THE INVENTION IN GENERAL 
     This invention relates to a pump assembly, and more particularly, to one wherein means such as a servo pump are employed to impulse a bladder-like device which in turn impulses a retention chamber to pressurize a fluid retained therein. The servo pump may be operated to provide a single, sustained pulse; or it may be operated to provide intermittent pulses which are interspaced with alternate intake or suction pulses in the chamber. 
     There is no necessity for contact between moving parts in the pump assembly, and the assembly can produce a high capacity flow, even of heavily slurried liquids. The assembly is also reducible to a highly compact form, and it can be directly driven by the servo pump, or it can be remotely operated at great distances from the site of the servo pump, including at great depths in the surface of the earth, as for example, when it is used as a down-the-hole pump. The assembly is also convertible in part to other purposes, including earth drilling. For example, as shall be seen, the assembly combines a conduit and an interior pulse generating mechanism, and if desired, the pulse generating mechanism can be removed from the conduit to enable the conduit to be used for these other purposes, such as for earth drilling purposes. Alternatively, the mechanism may be maintained in the conduit, and operated either concurrently with the drilling operation, or alternately therewith. 
     Other advantages will also become apparent as the invention is described in more detail. 
     According to the invention, the pump assembly comprises means defining a fluid retention chamber having an inlet opening and an outlet opening therein, and check valve means adjacent the inlet and outlet openings, which are operative to limit the fluid flow therethrough to relatively inward and outward of the chamber, respectively, when there is a fluid pressure differential thereacross. The pump assembly also comprises hollow pulse generating means in the chamber, having a volume of less than that of the chamber, but including a normally contracted, resiliently flexible portion which is responsive to a fluid pressure pulse in the hollow of the pulse generating means, to flex in relation to the normally contracted condition thereof. It also comprises impulsing means which are operative to impart a fluid pressure pulse to the hollow of the pulse generating means, to cause the flexible portion of the pulse generating means to flex and impart a fluid pressure output pulse to a fluid medium retained in the chamber. 
     The chamber defining means may be rigid such that the volume of the chamber remains the same as the resiliently flexible portion of the pulse generating means undergoes flexure therein. Or the chamber defining means may include a relatively shiftable portion which is interconnected with the pulse generating means and responsive to flexure of the resiliently flexible portion thereof to vary the volume of the chamber. 
     The pulse generating means and the chamber may be coaxial with one another; or they may have relatively offset axes. Also, the pulse generating means and the inlet and outlet openings may be coaxial with one another so that the fluid passes about the pulse generating means in flowing between the openings; or the pulse generating means and the openings may have relatively offset axes so that the fluid bypasses the pulse generating means in flowing between the openings. However, in the latter case, the inlet and outlet openings themselves are preferably coaxial with one another. 
     The impulsing means may include a servo pump which is operatively interconnected with the hollow of the pulse generating means. Also, the hollow of the pulse generating means may have a mandrel-like finger inserted therein, which occupies a substantial portion thereof. The finger may be closed to the hollow, or it may be open to the hollow and the servo pump may be operatively interconnected with the hollow through the opening of the finger. 
     In certain of the presently preferred embodiments of the invention, the pulse generating means is accordian-like in construction, and is connected at one end to the chamber defining means. Where the chamber defining means is rigid, the volume of the chamber remains the same as the pulse generating means deflects in accordian-like fashion. Where the chamber defining means includes a relatively shiftable portion, that portion is preferably interconnected with the other end of the pulse generating means, so that it is responsive to the lengthwise deflection of the same to vary the volume of the chamber. Where the hollow of the pulse generating means has a finger inserted therein, the finger is preferably coaxial with the pulse generating means. Where the finger is open to the hollow, and the servo pump is interconnected with the hollow through the opening of the same, the servo pump preferably includes a piston-like member which is reciprocably guided in the finger to impart the fluid pressure pulse adjacent the opening. Also, the finger is preferably cantilevered into the hollow from the one end of the pulse generating means, and the opening of the finger is adjacent but spaced from the other end thereof. The resiliently flexible portion of the pulse generating means is disposed about the outer periphery of the finger, and the finger has longitudinally extending flutes in the outer peripheral surface thereof, to enable the fluid in the hollow to move lengthwise of the finger when the resiliently flexible portion of the pulse generating means assumes the contracted condition thereof. 
     The servo pump may be operative to impart intermittent fluid pressure pulses to the hollow of the pulse generating means; or it may impart only a single pulse, whereafter the pulse is sustained by the servo pump. This will depend, of course, on the utility to which the invention is applied. 
     One utility for the invention is as a small diameter, large capacity down-the-hole pump. In this and other such cases, the chamber defining means may take the form of an elongated pipe having spaced partitions therein defining the chamber together with the pipe. The inlet and outlet openings are located in the partitions, and the servo pump is interconnected with the hollow of the pulse generating means by an elongated feed pipe passing through the bore of the chamber defining pipe and communicating with the hollow through the partition having the inlet opening therein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These features will be better understood by reference to the accompanying drawings wherein three of the aforementioned embodiments are illustrated. 
     In the drawings, FIG. 1 is a vertical cross section of one embodiment in use as a down-the-hole pump; 
     FIG. 2 is another such view in a different operative state; 
     FIG. 3 is an exploded perspective view of the pump assembly; 
     FIG. 4 is a part vertical cross section of the second embodiment; 
     FIG. 5 is a part longitudinal cross section of the third embodiment; and 
     FIG. 6 is a cross section along the line 6 -- 6 of FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring first to the embodiment in FIGS. 1 - 3, it will be seen that the pump assembly comprises an elongated carrier pipe 2 which may or may not be assembled from a plurality of coaxial sections, and in either event, the distal end of which is occupied by a flanged plug 4 which is inserted in the end and keyed or otherwise fixed to the pipe. The plug 4 has an annular recess 6 in the upper end thereof, and there is a series of symmetrically arranged ports 7 opening into the lower end of the plug from the recess. The ports are controlled by an elastomeric valve ring 8 which is disposed in the bore 9 of the pipe 2 and yieldably biased into engagement with the recess 6 in the plug. The bias is provided by a coiled spring 10 which is interposed between the valve ring 8 and an annular washer 12 which is seated on an expansible C-ring type clip 14 that is interengaged in a groove 16 (FIG. 1) in the inner peripheral wall 17 of the pipe above the plug. 
     The pump assembly also comprises an interior pulse generating mechanism 18 which is operative to produce fluid flow through the carrier pipe 2. The mechanism 18 includes a smaller diameter feed pipe 20 which is inserted in the proximal end portion of the carrier pipe and equipped with a bushed enlargement or head 22 on the distal end thereof. The head 22 is slidably insertable in the bore 9 of the carrier pipe, and when the mechanism is suitably positioned in the bore at a level above the plug 4, the head is pinned or otherwise fixed to the wall 17 of the pipe to form a sealed head wall or partition therein. The partition is ported, however, in that the head 22 has an annular recess 24 in the upper end thereof and there is a series of symmetrically arranged ports 25 opening into the bottom of the head from the recess. As with the plug 4, moreover, the ports 25 are controlled by an elastomeric valve ring 26 that is spring loaded into engagement with the recess by a washer 27-seated coiled spring 28. 
     The bushing 30 on the head 22 is an extension of the feed pipe 20, and supports an elongated resiliently flexible sleeve 32 which is suspended from the head into the chamber 34 defined by the head 22 and the plug 4. The upper end of the sleeve is tightly secured within an annular recess 36 in the bushing 30, to seal the sleeve to the head, and an annularly recessed cap 38 is similarly secured over the lower end of the sleeve to plug and seal that end as well. The sleeve has a hollow finger 40 upstanding in the bore thereof. The finger is tightly secured within an annular recess 41 in the upper end of the plug, so as to be sealed to the plug, and is slightly smaller in diameter than the bore of the sleeve, so as to develop a thimble-like cavity or hollow 42 therewithin. The hollow 42 communicates with the feed pipe 20 through the head and an air impulse servo pump 44 is interconnected with the feed pipe to supply intermittent fluid pressure pulses to the hollow 42, or alternatively, a single pulse which is then sustained by the servo pump. Each pulse inflates the sleeve 32 in the manner of FIG. 2, and causes it to swell into engagement with the wall 17 of the carrier pipe. The pulse also causes the sleeve to contract in the lengthwise direction, and therefore, the finger 40 is considerably shorter in length to accommodate to the contraction without abutting the bushing 30. Of course, depending on the magnitude of the pulse, the sleeve 32 may swell to a diameter of less than that of the wall 17, so that the sleeve does not engage the wall in all cases. In every case, however, the input pulse to the sleeve has the effect of generating an output pulse in the chamber 34, thus pressurizing the fluid medium in the chamber and causing it to open the valve 24, 26 and escape through the same into the proximal end portion of the bore 9 of the carrier pipe 2. Simultaneously, the output pulse maintains the valve member 8 in closed condition; but upon cessation of the input pulse to the sleeve, the valve 6, 8 is opened and more fluid enters the chamber through the ports 7 to be pumped into the proximal end portion of the bore 9 on the next input pulse. 
     The distal end 4 of the pump assembly may be inserted in a hole 46 and immersed in the fluid to be pumped, such as a body of water 48 standing in the bottom of the hole. Or an intake pipe (not shown) may be added to the end of the assembly to reach the fluid. 
     Either a gas or liquid may be employed to pulse the sleeve 32. When a gas is used, the hoop tension in the sleeve may be relied upon to collapse it to the contracted condition of FIG. 1 after each pulse. However, when a liquid is employed, a suction effect must be generated in the sleeve alternately with the input pulses, to assure that the fluid in the chamber 34 collapses the sleeve at a practical rate. 
     The pump chamber 34 needs no priming inasmuch as the initial input pulses clear the chamber of any air, whereafter the resulting vacuum induces the liquid to enter the chamber through the valve 6, 8. 
     In FIG. 4, the bottom of the chamber 34 is closed by an annular member 62 which is interconnected with a cap 50 on the lower end of the sleeve 32, to vary the volume of the chamber as the sleeve flexes lengthwise during pulsing. The cap 50 is extended lengthwise of the sleeve to accommodate a T-valve 52 having a ball-check valve member 54 in the bore 56 thereof. The ball cooperates with an opening 58 at the lower end of the cap, and there are four symmetrically arranged ports 60 about the upper end of the bore which communicate with the chamber 9 or 34. The annular member 62 is disposed at a level below the ports, and takes the form of an annular diaphragm 62 of the rolling type having one or more inverted U-shaped folds 64 therein. The diaphragm is interconnected with the wall 17 of the pipe 2 whereby on contraction of the sleeve, the volume of the chamber is reduced by the fact that the diaphragm follows the sleeve and effectively shortens the length of the chamber. 
     Alternatively, a piston may be mounted on the lower end of the sleeve and slidably engaged with the wall 17 for this purpose. However, the diaphragm is preferred because it avoids the problem of moving parts which contact one another. 
     In FIGS. 5 and 6, the pump assembly includes a housing 66 which defines an elongated chamber 70 having eccentrically opposing nipples 72 and 74, respectively, on the opposite ends thereof. One of the nipples, 72, is ported and check valve controlled in the manner of the plug 4 in FIGS. 1 - 3, to perform as an inlet valve; whereas the other nipple, 74, is ported and check valve controlled in the manner of the head 22 in FIGS. 1 - 3, to perform as an outlet valve. Eccentric of the chamber, and on the opposite side thereof at the outlet end of the chamber, there is a third nipple 76 which has a bushed enlargement or head 78 thereon, that is similar to the head 22 in FIGS. 1 - 3, but unported. The nipple 76 is a separate fitting which is secured to the housing in an opening 80 so that the head 78 projects into the chamber. The head in turn is equipped with an elongated resiliently flexible sleeve 82 which has a plug 84 at the free end thereof. Interiorly, the sleeve is also equipped with a finger 86 which performs as a filler in the manner of the finger 40 in FIGS. 1 - 3. However, in this instance the finger is secured to the head and is open-ended adjacent the plug. Also, the finger has a piston 88 slidably engaged therein, the drive rod of which, 90, is slidably engaged in the bore 92 of the nipple 76. A hydraulic fluid 94 is captive in the sleeve and is compressed by the piston on its inward stroke, there being longitudinally extending flutes 96 in the exterior surface of the finger whereby the fluid moves lengthwise of the sleeve to inflate it as shown. Conversely, on its outward stroke, the piston generates a suction effect which collapses the sleeve around the exterior surface of the finger, as shown by the dot-dash condition of the sleeve in FIG. 5. Where the assembly is used as a force pump, the drive force for the piston is provided by a reciprocating drive mechanism (not shown) which is interconnected with the rod 90. Otherwise, such as where the assembly is used as a simple pressure applicator, the piston may be driven by a ram drive mechanism, also not shown. 
     Alternatively, the sleeve 32 or 82 may be secured at its ends to the surrounding walls of the chamber 34 or 70, and the walls may be equipped with one or more ports through which the inflation fluid is introduced and/or compressed around the sleeve, to flex the sleeve under tension inwardly of its diameter, rather than outwardly of its diameter as in FIGS. 1 - 6. 
     The sleeve 32 or 82 is preferably a braided wire reinforced elastomeric material. One such material is made by the Kleber Company of Paris, Cedex 16, France. Alternatively, the material can be expanded rubber or some other material which is suited to the function of the sleeve. 
     When the pulse generating mechanism 18 is employed in a convertible assembly, the subassembly 22, 26, 27, 28 is adapted as a piston-like member which is slidably engageable in the bore of a pipe such as the pipe 2, and equipped with latch means which are operative to interengage and lock the member to the pipe at a selected location therein. For example, see U.S. Pat. No. 3,292,717 for an example of such a latch means. The plug assembly 4, 8, 10, 12 may be adapted as a similarly equipped piston-like member which is engageable in the pipe at a more advanced location; or the pipe itself may be equipped with a preassembled plug assembly; or a single pipe section may be so equipped for insertion in a pipe string; or the sleeve 32 may have a piston-like member on the lower end thereof which is adapted to form the necessary lower chamber defining partition. 
     In some down-the-hole applications a column of liquid or similar medium may be used to maintain a piezometric head in the sleeve 32 or 82, which is substantially equal to the hoop tension of the same, so that on application of pressure to the medium the sleeve will immediately undergo expansion. That is, the height of the column can be set to assume a state of equilibrium with the hoop tension in the sleeve and any external pressure on the same, so that the applied pressure has an immediate effect on the sleeve. This also has the advantage of providing a constant relationship between the magnitude of the respective impulses and outpulses, such that the pump can be used to meter a steady flow. 
     Likewise, other means can be employed to equalize the flow from the pump. For example, the pump may be operated in conjunction with one or more other similar pumps to produce a smoother flow pattern, as for example, by interconnecting them through a swashplate or a shuttle valve.