Patent Publication Number: US-2005123416-A1

Title: Combined piston fluid motor and pump

Description:
This application claims the benefit of the filing date of U.S. Provisional Application No. 60/527,699, filed Dec. 6, 2003. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates generally to fluid motor devices capable of converting a portion of the energy of a fluid flow into a reciprocating movement. More particularly, the present invention relates to devices comprised of a fluid motor coupled to a fluid pump.  
     BACKGROUND OF THE INVENTION  
      Fluid pumps may be powered by electric motors or by fluid motors. Fluid pumps driven by electric motors have a number of undesirable attributes. For example, in some applications, fluid pumps using electric motors are undesirable for safety reasons. For instance, when pumping solvents, acids, oils, and flammable liquids, it can be disadvantageous or even dangerous to operate high voltage or high current electric motors to drive the pumps. As another example, fluid pumps using electrical motors do not easily start from a stalled condition and stop into a stalled condition. Such intermittent fluid flow is desired in some applications, requiring cyclic starting and stalling of the flow.  
      Current fluid motors and pumps may have valve ports that limit fluid flow through the unit in a manner that results in pressure drop and turbulence through the motor. When a powering fluid is saturated with a gas, for example, gas saturated carbonated water, too much pressure drop and turbulence through a fluid motor may cause the CO 2  to bubble out of the solution, adversely affecting precision as a fluid powered proportioning pump for carbonated water and syrup. In addition, internal valve leakage in the motor while shifting may adversely affect precision as a fluid powered proportioning pump.  
      Three devices that may be representative of the art include: a nonelectric proportional dispenser from Dosatron International of 2090 Sunnydale Blvd., 40 Clearwater, Fla. 33765 (phone: 727-443-5404; fax: 727-447-0591); a brix pump from Shurflo of 12650 Westminister Ave., Santa Ana, Calif. 92706-2100 (phone: 714-554-7709; fax: 714-554-4721); and Dosmatic USA of 1230 Crowley Circle, Carrollton, Tex. 75006 (phone: 972-245-9765 fax: 972-245-9000). These devices use water pressure as the power source to operate a fluid powered, piston proportioning pump.  
     SUMMARY OF THE INVENTION  
      One exemplary aspect of the invention is directed to a device utilizing a fluid motor. The device comprises a housing and a reciprocating piston in the housing. The piston and the housing may be configured to define at least two variable-volume chambers. A multi-port valve may be associated with the piston, and may be in communication with the at least two chambers. A valve actuating mechanism may be configured to actuate the multi-port valve to affect a fluid path in the device. The device may also include a valve engagement-release mechanism configured to maintain the multi-port valve in a position when the valve is not being actuated. An inlet port and an outlet port may be in selective communication with each piston chamber through the multi-port valve.  
      In another exemplary aspect, a method for operating a fluid motor having a first and a second fluid chamber separated by a reciprocating piston is disclosed. The fluid motor may have an inlet port and an outlet port. The method may include introducing fluid to the first chamber through the inlet port, the inlet port being in fluid communication with the first chamber. The volume of the first chamber may be increased by moving the piston. Energy may be stored in a valve actuating means, wherein the energy may be provided by the moving piston. The method may also include shifting a valve member by releasing the stored energy to close the fluid communication between the inlet port and the first chamber, and to place the inlet port and the second chamber in fluid communication. Fluid may then be introduced to the second chamber through the inlet port. The volume of the second chamber may then be increased by moving the piston.  
      The device of the present invention may be used as a fluid motor coupled to a fluid pump. The flow and pressure of a first fluid through a reciprocating piston, fluid motor mechanically coupled to a reciprocating, fluid pump causes a flow and pressure of a second fluid in a predetermined ratio. It is not necessary for the flow and pressure of the first fluid to be the same as the flow and pressure of the second fluid.  
      The device of the present invention may have a utility for a variety of diverse applications without the need of electrical energy. Examples of such applications include, but are not limited to, proportioning, sampling, metering, flow detection, energy recovery, pressure intensification, and pumping. The device of the present invention may have advantages of cost, performance, simplicity and materials sufficient to displace devices in existing applications and enable potential new applications. Typically, two or more streams (liquid or gas) will be proportioned where one stream has a source pressure higher than its destination pressure and serves as an energy source to operate a reciprocating motor and the other streams have a source pressure lower than its destination pressure and use a pump powered by a motor to provide pressure and proportioning.  
      Examples of applications where a fluid pumped or maintained under pressure include the pumping of water, solvents, acids, oils and flammable liquids. As stated above, in some of these applications, an electric motor is disadvantageous for safety reasons. Further, some of these applications require starting from a stalled condition and stopping into a stalled condition and are not easily accomplished with an electric motor. Double diaphragm gas operated pumps may be used. The present invention can use either a pressurized fluid or a pressurized gas.  
      For applications involving both the pressurization of a fluid and the discharge of a pressurized fluid, waste energy may be reclaimed by the present invention. An example is reverse osmosis where the feed water is pressured by a pump to drive the water through a semi-permeable membrane. Most of the pressurized water is discharged to drain with no re-use of pressurization energy. The present invention can use the energy of the pressurized discharge water to provide most of the pressurization of the feed water, consequently reducing the pump and motor requirements for feed water pressurization. For example, this is advantageous where available energy is limited such as on submarines or mobile potable, water purification equipment for soldiers.  
      The system of the present invention may be used in applications where a fluid is de-pressurized and then re-pressured. An example is an ambient pressure solar water heater where ambient temperature, pressurized domestic water is de-pressurized to fill an atmospheric pressure solar collector of the black bag type. Heated water from the collector is re-pressurized to provide flow to faucets and appliances. Use of the present invention, simplifies and lowers the cost of the solar system by using the pressure of the unheated incoming water to re-pressurize the heated collector water in a one to one ratio.  
      The system of the present invention may be used in applications where a small flow of high pressure fluid is desired and a large flow of low pressure fluid is available. An example is a hydraulic intensifier where the energy of a high flow of low pressure hydraulic oil may be used to operate the fluid motor of the present invention which in turn operates a smaller cross section pump to create a low flow of high pressure hydraulic oil. The increase in pressure is proportional to the ratio of the flows and therefore the cross sections of the motor and pump.  
      The system of the present invention may be used in applications where two or more fluids are mixed in a predetermined adjustable or non-adjustable ratio. Examples include: diluting and mixing herbicides and pesticides into water for agricultural spraying, diluting and mixing fertilizer into irrigation water for agricultural and horticultural use, diluting and mixing soap concentrate into water for washing equipment for clothes, dishes, parts and the like, diluting and mixing an oil concentrate into water for machine tool lubrication, and for the addition of chemical into the make-up water of process tanks. The present invention may function in this application by using the flow and pressure of the water as the first fluid for the fluid motor. The additive fluid as the second fluid is pumped by the fluid pump in a ratio proportional to the cross sections of the fluid motor and fluid pump times their effective stroke. The discharge of both may then be mixed.  
      The system of the present invention may be used in applications that require indicating a flow rate or totalizing a flow. The flow to be measured is used as the fluid through the fluid motor. At least one sensor may detect the reciprocating motion of the piston. The signal from the sensor provides information convertible into flow rate or total flow information. A sensor may be provided that can detect the piston motion without direct contact, without a shaft penetrating the housing.  
      The system of the present invention may be used in sampling applications. The fluid to be sampled powers the fluid motor. The fluid pump may draw some of the discharge fluid of the fluid motor as a second fluid. The flow from the fluid pump may be the sample. The sampling ratio may be proportional to the ratio of the cross section of the fluid pump and motor.  
      A common application particularly suited to the present invention is the post mix beverage dispenser. Since pressurized domestic water is almost always available the device of the present invention may be substituted for the compressed, carbon dioxide gas operated “bag-in-the-box” syrup pump by using the domestic water as an energy source and then sending the spent water to drain. Using the energy of the carbonated water to pump and proportion the syrup may make an even more advantageous use of the present invention. In this way, the present invention replaces both the conventional syrup pump and the proportioning part of the dispensing valve, further simplifying the dispenser and lowering its manufacturing cost.  
      The system of the present invention may be used in applications such as fuel cells that use different phases. Compressed air can power the reciprocating motor that powers a fuel pump and a water pump in a desired proportion. The discharge of all three may then be directed into a reformer.  
      The present invention has advantages in these applications because no electricity is required for power or control. The invention operates as a fluid motor, a fluid pump, a combined fluid motor and pump, or proportioning device as needed by the application. The present invention ceases operation when the flow of one or more fluids is ended, and the invention will resume operation when the flow is re-established, i.e. the device is stallable.  
      The present invention may have a fluid motor similar in construction to the common air and hydraulic tie rod design and actuating cylinders. This construction is easy and economical to manufacture and capable of withstanding pressures from 100 psi to thousands. The present invention may be used in applications under such pressures. The present invention may have a hydraulically balanced multi-port valve with substantially no internal leakage when shifting. This feature provides several important advantages over products currently commercially available: (1) The force required to shift the multi-port valve does not vary substantially with either an increasing pressure differential across the motor or increase of the valve port cross sectional area. (2) Therefore, a given valve actuation mechanism and a given valve release mechanism can operate over a wider range of flows and pressures than fluid motors now manufactured. (3) Since there is no design penalty for larger valve port cross sections, a motor of the present invention can be made with large valve ports thereby reducing the pressure drop and turbulence through a motor.  
      Thus, the present invention aids in avoiding at least two problems that limit the utility and applications of other designs: (1) when a powering fluid is saturated with a gas, like carbonated water is, too much pressure drop and turbulence through a fluid motor will cause the CO2 to bubble out of solution and adversely affect precision as a fluid powered proportioning pump for carbonated water and syrup; and (2) a multi-port valve allowing internal leakage while shifting also adversely affects precision as a fluid powered proportioning pump.  
      The present invention may be compatible with embodiments having different features. The present invention describes two exemplary types of valve actuation means: spring and magnetic, although other types of actuation means are considered. In the magnetic, the valve actuating mechanism may include at least two magnets having a polarity oriented in a manner that one magnet repels the other magnet. The present invention also describes three exemplary types of valve release mechanisms: mechanical trigger, mechanical over-the-center, and magnetic, although other types are considered. The present invention may include a stroke compensator to make the ratio of a fluid powered proportioning pump with double acting pump the same in both stroke directions. The present invention contemplates the use of single acting, double acting, external, internal, fixed ratio, adjustable ratio, multiple, and single pumps. The present invention describes a stroke signal means usable for flow control, flow rate measurement and flow totalizing.  
      This invention may provide device functioning as a combined fluid motor and pump of unusual simplicity and low part count.  
      This invention is consistent with requirements for injection molded, polymer parts and automated or mechanized assembly allowing the potential for low cost mass production. It is also consistent with requirements for metallic parts in applications where stresses are too great for polymer parts.  
      This invention has numerous useful embodiments suitable for a wide range of applications. Although the invention may be used with additional features, some exemplary embodiments include the following: 
          (1) fluid motor with end inlet and outlet ports;     (2) fluid motor with a direct or indirect stroke sensor;     (3) fluid motor with shaft and external pump or pumps;     (4) fluid motor without shaft and internal adjustable pump or pumps;     (5) fluid motor with internal and external pumps;     (6) fluid motor with external pump resistant to cross-contamination;     (7) hydraulically unbalanced multi-port valve;     (8) hydraulically balanced multi-port valve;     (9) low leakage multi-port valve; and     (10) stall resistant, hydraulically balanced, low leakage multi-port valve.        

      It is another object of the present invention to provide a device that converts a first fluid flow and pressure into mechanical motion by means of a fluid motor part of the device and using this mechanical motion converts it into fluid flow and pressure by means of a fluid pump part of the device.  
      It is another object of the present invention to provide a fluid motor where the energy for valve actuation is supplied by piston displacement.  
      It is another object of the present invention to provide a fluid motor where the energy for valve actuation is stored and released in springs.  
      It is another object of the present invention to provide a fluid motor/pump where valve actuation is enabled by proximity of the piston to the end of its chamber.  
      It is another object of the present invention to provide a device that operates without need of electrical control or power.  
      It is another object of the present invention to provide a device that will stop and restart in response to a first fluid&#39;s flow and pressure.  
      It is another object of the present invention to provide a device that will stop and restart in response to a second fluid&#39;s flow and pressure.  
      It is another object of the present invention to provide a fluid motor that will stop and restart in response to input fluid flow and pressure.  
      It is another object of the present invention to provide a fluid motor that will stop and restart in response to shaft pressure.  
      It is another object of the present invention to provide accurate, volumetric proportioning of two or more fluids.  
      It is another object of the present invention to provide fluid motor driven proportioning pump of a fixed ratio.  
      It is another object of the present invention to provide a fluid motor driven proportioning pump of an adjustable ratio.  
      It is another object of the present invention to provide a device where the fluids may be either liquid or gas.  
      It is another object of the present invention to provide a device with a means of sensing the reciprocating motion for control and measurement purposes.  
      The above objects are exemplary only, and this invention contemplates devices and systems that may meet or fulfill one or more of these objects. Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. In addition to the structural and procedural arrangements set forth above, the invention could include a number of other arrangements such as those explained hereinafter. It is to be understood that both the foregoing general description and the following detailed description are exemplary only. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings illustrate embodiments of the invention and together with the description, serve to explain some exemplary embodiments and principles of the invention.  
       FIG. 1  is pictorial representation of a trimetric, general arrangement of an exemplary end port motor combined with an exemplary close coupled, shaft connected, fixed displacement pump in one exemplary embodiment of the present invention.  
       FIG. 2  is a pictorial representation of a trimetric, general arrangement of an exemplary end port motor combined with an exemplary shaft-less, adjustable displacement pump in another exemplary embodiment of the present invention.  
       FIG. 3  is a pictorial representation of a side view cross section of an exemplary end port motor.  
       FIG. 4  is a pictorial representation of a top view cross section of an exemplary end port motor with a piston approaching the end of its stroke.  
       FIG. 5  is a pictorial representation of a top view cross section of an exemplary end port motor with a piston approaching the end of its stroke.  
       FIG. 6  is a pictorial representation of a side view cross section of an exemplary end port motor combined with an exemplary close coupled, shaft connected, fixed displacement pump in one exemplary embodiment of the present invention.  
       FIG. 7  is a pictorial representation of a front cross section of the exemplary fluid motor of  FIG. 6  looking away from a fluid pump.  
       FIG. 8  is a pictorial representation of a front cross section of the exemplary fluid motor of  FIG. 6  looking toward the fluid pump.  
       FIG. 9  is a pictorial representation of a top view cross section of an exemplary end port motor combined with an exemplary shaft-less, adjustable displacement pump in another exemplary embodiment of the present invention.  
    
    
     DESCRIPTION OF THE EMBODIMENTS  
      Reference will now be made in detail to exemplary embodiments of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
       FIG. 1  shows a trimetric, general arrangement of an exemplary end port motor combined with an exemplary close coupled, shaft connected, fixed displacement pump in one exemplary embodiment of the present invention. A exemplary fluid motor housing is comprised of end cap  210 , casing  196  and end cap  350 . End cap  350  contains inlet port  180  and outlet port  182 . End cap  350  and end cap  210  may be connected to casing  196  using any attachment system, including, for example, dowels  224 .  
      An exemplary fluid pump is comprised of housing segments  228 ,  230  and  232 . Segment  230  contains pump inlet port  162  and pump outlet port  236 . Segments  232 ,  230 ,  228 , and end cap  210  may be held together in compression by fasteners  192 , such as, for example, rods and bolts. Pump ports  162  and  236  are shown as tubes suitable for the “instant” type tube connection. These ports along with fluid motor ports  180  and  182  could just as well be another type of fitting such as, for example, screw, flange, or flare.  
       FIG. 2  shows a trimetric, general arrangement of an exemplary end port motor combined with an exemplary shaft-less, adjustable displacement pump in an exemplary embodiment of the present invention. A exemplary fluid motor housing is comprised of end cap  310 , casing  196  and end cap  322 . End cap  322  may contain inlet port  180  and outlet port  182 . End cap  322  and end cap  310  may be connected to casing  196  using any system, such as, for example, dowels  224 . The visible portion of the pump is shown as inlet port barb fitting  300 , inlet stem  304 , and compression nut  306 . In the exemplary embodiment of  FIG. 2 , pump port  300  is shown as a barb type connection. This port along with fluid motor ports  180  and  182  could just as well be another type of fitting such as, for example, screw, flange, or flare.  
       FIG. 3  shows a side view cross section of an exemplary fluid motor of an end port embodiment. In use, fluid enters and leaves through inlet port  180  and outlet port  182  (not shown) located in an end cap  350 . A fluid motor housing may be comprised of motor case  196 , end cap  186  and end cap  350 . End cap  186  and end cap  350  may be connected to case  196  using any system, such as, for example, by pins  224  and sealed by o-rings  120 . A variable volume chamber  204  may formed by a piston assembly, the interior surface of case  196 , and the interior surface of end cap  186 . Likewise, a variable volume chamber  212  may be formed by a piston assembly, the interior surface of case  196 , and the interior surface of end cap  350 .  
      A shaft  118  may be fastened to a piston assembly. Shaft  118  may penetrate end cap  186  and may be sealed by a shaft seal assembly comprised of seal  129 , seal bushing  128 , and seal retainer  192 . In the exemplary embodiment shown, the piston assembly is comprised of piston body  216  and piston body  214 . Variable volume chamber  212  and variable volume chamber  204  are isolated by piston ring seal  70  and o-ring  72 .  
      A multi-port valve may be located within a piston assembly. An exemplary multi-port valve is shown in  FIG. 3  and includes a poppet valve assembly slidably located within piston body  216  and piston body  214 . The poppet valve assembly may include actuating spring  98  fixed to spring mount  97 . Spring mount  97  is in turn mounted to valve member  107 . On the other side of the piston, a second poppet valve assembly may include actuating spring  100  fixed to spring mount  96 . Spring mount  96  is in turn mounted to valve member  106 . Inlet poppet  237  and inlet poppet stem  233  may be fastened to cross member  107  and cross member  106  using any known system, including a threaded rod  104  and nut  102 . Outlet poppet  239 , outlet poppet  241 , and outlet poppet stem  231  may also be fastened to cross member  107  and cross member  106  by any known system, such as threaded rod  104  and nut  102 .  
      Inlet port  180  (shown in  FIG. 1 ) may communicate with cylinder chamber  204  through a passage comprising inlet passageway  240 , then inlet distribution chamber  235  (shown in  FIG. 4 ), then inlet seated passageway  84 , then chamber  142 , then passageway  222 , and finally chamber  204 . In the exemplary embodiment shown, inlet port  180  (shown in  FIG. 1 ) is blocked from communication with cylinder chamber  212  when the inlet port  180  is in communication with cylinder chamber  204 . However, when inlet port  180  is in communication with cylinder chamber  212 , it may communicate with the chamber through a passage comprising inlet passageway  240 , then inlet distribution chamber  235 , then inlet seated passageway  82 , then chamber  61 , then passageway  218 , and finally chamber  212  by poppet  237  resting on and blocking seated passageway  84 .  
      Outlet port  182  (shown in  FIG. 1 ) may communicate with cylinder chamber  212  by means of outlet passageway  247 , then outlet seated passageway  253 , then distribution passageway  243 , then chamber  61 , then passageway  218 , and finally chamber  212 . In the exemplary embodiment shown, outlet port  182  (shown in  FIG. 1 ) is blocked from communication with cylinder chamber  204  when the outlet port  182  is in communication with cylinder chamber  212 . However, when outlet port  182  is in communication with cylinder chamber  204 , it may communicate with the chamber through a passage comprising outlet passageway  247 , then outlet seated passageway  251 , then distribution passageway  245 , then chamber  142 , then passageway  222 , and finally chamber  204  by poppet  239  resting on and blocking outlet seated passageway  253 .  
      A valve magnet  94  may be fixed in position within piston body  214  and piston body  216 . Valve magnet  94  may exert an attractive force upon spring mount  97  due to its proximity holding a slidable poppet assembly in place at its limit of travel in direction  213 .  
      In some exemplary embodiments, when a poppet assembly shifts from one position to another, at least a portion of the fluid may flow from the inlet to the outlet without acting on a piston, thereby forming a leak. The volume leaked can be reduced by, for example, shifting the poppet assembly quickly. Leakage can also be reduced by providing poppets that substantially block the undesirable flow path even as the poppets shift, as in a low leakage valve of  FIG. 6 . In the example shown in  FIG. 3 , poppet member  237  has a cross section nearly equal to inlet distribution chamber  235 . In this case, member  237  may be cylindrical in shape. The length of member  237  may be slightly greater than width of passageway  240  so that as member  237  shifts from one position to another, member  237  substantially blocks passageway  240  as it passes over. In this way, fluid exiting inlet distribution chamber  235  has a pathway to either chamber  142  or chamber  61 , but not both at the same time. Likewise, poppet member  239  may have a cross section nearly equal to passageway  243 , and poppet  241  may have a cross section nearly equal to passageway  245 . Furthermore, the lengths of poppet  239 , poppet  241  and passageway  243 , passageway  245  may be greater than one half of the shifting distance. In this way, fluid entering outlet distribution chamber  247  has a pathway from chamber  61  or chamber  142 , but not both at the same time as the poppet shifts.  
      In use, a piston assembly advances in direction  213 . A powering fluid enters the fluid motor through inlet port  180  (shown in  FIG. 1 ) and may fill chamber  204  causing the advance of a piston assembly in direction  213  as the volume of chamber  204  increases. The advance of a piston assembly in direction  213  reduces the volume of chamber  212  and may expel a powering fluid through outlet port  182  (shown in  FIG. 1 ). As shown in the exemplary embodiment of  FIG. 3 , valve actuating spring  100  has made contact, due to the advancing of the piston assembly, with the interior surface of end cap  350 . Further advancement of the piston further compresses spring  100 . The energy stored by compression of spring  100  results in a force acting on a poppet assembly biasing it in direction  41 .  
      Countering the force in spring  100  is a force on a poppet assembly biasing it in direction  213  by magnetic attraction between magnet  94  and spring mount  97 . By design, with the continued advance of the piston and the subsequent further compression of spring  100 , the force from spring  100  in direction  41  will eventually exceed the opposing force in direction  213  by magnet  94  and mount  97 . At that time, a poppet assembly will slidably shift rapidly to its alternate limit of travel in direction  41 . The increased distance between magnet  94  and spring mount  97  results in negligible attractive force. However, with the shift of the poppet assembly, magnetic  94  and spring mount  96  are in proximity and the attractive force is significant and sufficient enough to hold a poppet assembly in place at the limit of travel in direction  41 .  
      With a shift of a poppet assembly, the powering fluid may be re-directed. Thus, the powering fluid may enter inlet port  180  and ultimately into cylinder chamber  212 . Since there is no exit from chamber  212 , the volume increases as a piston is displaced in direction  41 . With the displacement of a piston in direction  41 , the volume of cylinder chamber  204  is reduced, expelling a powering fluid to outlet port  182 . As a piston advances in direction  41 , actuating spring  98  will eventually make contact with end cap  186 . Further advance causes further compression of spring  98 . Ultimately, the force resulting from compression of spring  98  will exceed and overcome the force between magnet  94  and spring mount  96  causing a rapid, slidable shift of a poppet assembly in direction  213 . Thus, another cycle begins, with the reciprocation of a piston within its cylinder and with the reciprocation of a poppet assembly within its valve.  
      In the exemplary embodiment shown, the fluid path is from the inlet to a valve in the piston, and from a valve to a variable volume cylinder chamber, and from the other cylinder chamber to a valve in the piston, and from a valve to the outlet. The fluid does not flow from one cylinder chamber through a piston to the other cylinder chamber as in other devices of prior art.  
       FIG. 4  shows a top view cross section through an inlet port of an exemplary end port motor embodiment with a piston approaching the end of its stroke. A piston assembly includes piston member  216  and piston member  214  joined by a fastener (not shown). A pressurized, powering fluid flows into the piston of the motor through inlet port  180 , passageway  184 , and inlet piston tube  194 . Inlet piston tube  194  may be fixed in end cap  350 . Tube  194  may slidably engage piston tube chamber  206  and may be isolated from variable volume chamber  212  by a seal assembly comprised of seal  202 , seal bushing  190 , and seal retainer  200 . In use, fluid may exit tube  194  to enter chamber  206  and continue through passageway  240  into inlet distribution chamber  235 . In the exemplary embodiment shown, since inlet seated passageway  82  is blocked by poppet member  237 , fluid may exit from chamber  235  through inlet seated passageway  84  into chamber  142  and then through passageway  222  into a closed, variable volume cylinder chamber  204 . Chamber  204  may be comprised of surfaces of end cap  186 , motor casing  196 , and piston member  214 . Chamber  204  may be sealed using a seal, such as, o-ring seal  120 . Chamber  204  may be isolated by using any sealing system, such as, for example, sliding piston ring  70  and o-ring  72 . As chamber  204  fills a piston assembly is pushed in direction  213 .  
       FIG. 5  shows a top view cross section through an outlet port of an exemplary end port motor embodiment with a piston approaching the end of its stroke. As a piston assembly advances in direction  213 , variable volume chamber  212  decreases in volume. The displaced fluid may be forced out through passageway  218  into chamber  61 . Fluid exits chamber  61  through distribution chamber  243  and then through seated passageway  253  into outlet collection chamber  247 . Seated passageway  251  may be blocked by poppet member  241 . A fluid exits outlet chamber  247  through passageway  208  into piston tube chamber  207 . A fluid continues through piston tube  195  into passageway  183  into outlet port tube  182  to finally exit. Tube  195  slidably engages piston tube chamber  207  and may be isolated from variable volume chamber  212  by a seal assembly that may comprise, for example, seal  202 , seal bushing  190 , and seal retainer  200 .  
       FIG. 6  shows a side view cross section of an exemplary end port motor using a hydraulically balanced multi-port valve combined with an exemplary close coupled, shaft connected, fixed displacement pump in one exemplary embodiment of the present invention. This embodiment illustrates a mechanical valve release substituted for a magnetic release. In addition, this embodiment illustrates a low leakage valve where the inlet communicates with one piston chamber at a time, and where the outlet communicates with one piston chamber at a time, and where the inlet and outlet cannot communicate with one another while a valve shifts position.  
      In some exemplary embodiments, multiple seals may be utilized to isolate a fluid motor and pump. The seals may be spaced to provide a gap between the seals greater than the piston stroke so that no part of the shaft that is exposed to the fluid of the motor is exposed to the fluid of the pump. In the exemplary embodiment shown in  FIG. 6 , shaft seal  360  isolates a fluid of the motor from a fluid of the pump. A shaft assembly comprised of seal  129 , seal bushing  128 , and seal retainer  191  further isolates a fluid of the motor from a fluid of the pump. An air vent  123  may optionally provide communication between the atmosphere and a chamber formed between multiple shaft seals or a chamber occupied by a barrier fluid. Depending on the application, seal  360  and seal  129  may be an o-ring, lip seal, piston ring, or other sealing system, including, for example, a diaphragm or bellows shaft seal.  
      A pump housing may be comprised of housing segments  228 ,  230  and  232 . The segments may be connected together and to motor end cap  121  by a fastener  192 . The fastener could be any system or method that holds the different components together. Segments  228 ,  230 ,  232  and end cap  121  may be sealed using any seal, such as, for example, o-rings  351 .  
      The reciprocating motion of a motor piston may be transmitted to a pump piston  353  that may be fixed to shaft  118  by a fastener, such as fastener  355 . Piston  353  may slide in a pump bore  359  separating the bore into two variable volume chambers  357  and  358 . Chamber  357  may be defined by surfaces of pump bore  359 , piston  353 , and housing segments  230  and  232 . Likewise, chamber  358  is defined by surfaces of pump bore  359 , piston  353 , and housing segments  228  and  230 . Chamber  357  may be isolated from chamber  358  using any seal or system, such as, for example, piston seal  354 . Depending on the application, seal  354  may be an o-ring, lip seal, piston ring, or other seal or gasket.  
      In use, a pumped fluid enters tube inlet port  162  (shown in  FIG. 1 ) to inlet distribution chamber  375 . The pump fluid exits outlet distribution chamber  376  to tube outlet port  236  (shown in  FIG. 1 ). A pumped fluid may exit chamber  375  through either one way check valve  364  or check valve  363 , depending on the direction of movement by piston  353 . In the exemplary embodiment shown in  FIG. 6 , piston  353  is moving in direction  370  and, therefore, a pumped fluid is drawn into chamber  357  through check valve  364 , then through passageway  356 . A pumped fluid may enter outlet distribution chamber  376  through either one way check valve  362  or check valve  361  depending on the direction of movement by piston  353 . Movement of piston  353  may displace a pumped fluid in chamber  358  through passageway  365 , through check valve  361  into outlet distribution chamber  376 , and then exiting through tube outlet port  236 .  
      In other exemplary embodiments, shaft  118  is extended and additional pumps are added and stacked in series. Thus, the motor is able to operate multiple pumps. In addition, by varying the cross section of pump piston and pump bore, displacement per stroke can be set independently. By this means, a powering fluid operating a fluid motor of this invention can pump one to multiple fluids in predetermined proportions. In the exemplary embodiment shown, the pump is a piston type. However, any type pump using the power of a reciprocating shaft may be used, including a diaphragm type pump. Furthermore, it should be noted that the disclosed design is compatible with all fluids, including liquids and gases. Thus, a gas may be substituted for one or more liquids, including a powering liquid.  
      The exemplary end port motor includes a housing assembly comprised of case  196 , end cap  121 , end cap  350 , seals  120 , and fasteners  224 . Shaft  118  is fixed to a piston assembly and protrudes through end cap  121  and into a pump. A piston assembly includes piston member  400  and piston member  401  that are joined by fastener  140  (not shown). A piston assembly may include a multi-port valve. The exemplary multi-port valve shown includes a valve retainer  403  and a valve retainer  404 . Outlet distribution spool  405  is fixed between piston member  400  and piston member  401  and may be sealed at piston members  400  and  401  by o-rings  406 . An annular chamber  407  in spool  405  may be communication with an outlet port  182 . The pathway from outlet port  182  to annular chamber  407  may include passageway  183 , outlet piston tube  195 , chamber  207 , and passageway  208  all of which are not shown except piston tube  195 . Valve holes  408  in spool  405  may provide communication between annular chamber  407  and cylinder chamber  204 . Valve holes  408  in spool  405  may also provide communication between annular chamber  407  and cylinder chamber  212 .  
      In the exemplary embodiment shown, an outlet valve poppet  409  with piston ring seal  410  slidably occupies spool  405 . The width of seal  410  is slightly wider than the diameter of holes  408  that seal  410  slides over. Therefore, holes  408  are configured to avoid communication with chamber  212  and chamber  204  at the same time. Fixed to poppet  409  on one side is rack member  411  and the other side is detent member  412 . Detent member  412  may be slidably restrained on three sides by valve retainer  404  and on the fourth side by roller  421 . Rack member  411  is slidably restrained on three sides by valve retainer  403  and on the fourth side by spur gear  414 .  
      Inlet distribution spool  415  may be fixed between piston member  400  and piston member  401  and may be sealed at piston members  400  and  401  by o-rings  406 . An annular chamber  416  in spool  415  may be in communication with an inlet port  180 . The pathway from inlet port  180  to annular chamber  416  may include passageway  184 , inlet piston tube  194 , chamber  206 , and passageway  240  all of which are not shown except piston tube  194 . Valve holes  408  in spool  415  provide communication between annular chamber  416  and cylinder chamber  204 . Valve holes  408  in spool  415  also provide communication between annular chamber  416  and cylinder chamber  212 .  
      An inlet valve poppet  417  with piston ring seal  418  slidably occupies spool  415 . The width of seal  418  may be slightly wider than the diameter of holes  408  that seal  418  slides over. Therefore, holes  408  do not communicate with chamber  212  and chamber  204  at the same time. Fixed to poppet  417  on one side is rack member  419  and the other side is detent member  420 . Detent member  420  may be slidably restrained on three sides by valve retainer  404  and on the fourth side by roller  421 . Rack member  419  may be slidably restrained on three sides by valve retainer  403  and on the fourth side by spur gear  414 . Additionally, spring mount  96  and valve actuating spring  100  may be fixed to rack  419 . A shoulder on mount  96  may make contact with valve retainer  403  to limit the travel of an inlet poppet assembly. Spring mount  97  and valve actuating spring  98  may be fixed to detent member  420 . A shoulder on mount  97  may make contact with valve retainer  404  to limit the travel of an inlet poppet assembly.  
      The exemplary multi-port valve shown, utilizes inlet and outlet poppet assemblies that shift positions when a piston reaches the end of its stroke to cause reversal of a piston&#39;s travel. An actuating spring compressed by a piston&#39;s advance on its end cap provides the force needed to accomplish the shift of poppet assemblies. Inlet and outlet poppet assemblies are configured to shift equal amounts, yet in opposite directions because of linkage provided by gear  414  and inlet rack  419  and outlet rack  411 . Gear  414  is rotatably fixed in valve retainer  403 . This feature is important in another regard, a multi-port valve having poppet assemblies that are linked and balanced on a common fulcrum may be hydraulically balanced. In a hydraulically balanced valve, regardless of the differential pressure from one cylinder chamber  204  to the other cylinder chamber  212 , the force required to actuate the valve shift is substantially constant. This allows the design of valve ports with generous openings resulting in lower pressure drop while keeping the valve actuating mechanism and valve release mechanism compact and subject to lower forces than is otherwise possible.  
      A valve release mechanism may be necessary to hold valve poppet assemblies in place while a valve actuating spring is compressed. Further, in the exemplary embodiments shown, a valve release mechanism should release valve poppet assemblies when an actuating spring is sufficiently compressed so that a valve actuating spring may act to shift valve poppet assemblies quickly and completely to the limit of their travel. Three types of exemplary release mechanisms are described in the present invention, although others are within the scope of the invention: first—a magnetic release as described in  FIG. 3 , second—an over-the-center mechanical release as described in  FIG. 6 , and third—a trigger type mechanical release as described in  FIG. 6 .  
      The valve release mechanism may include a torsion spring  425  to which detent roller  423  and detent roller  427  are fixed, yet free to rotate. Torsion spring  425  may act on detent roller  423  and detent roller  427  biasing them toward one another. The flexural extension of torsion spring  425  may be sufficient to allow detent roller  423  to clear a detent slot  424  in detent member  420 , yet insufficient to clear trapping slot  422  in valve retainer  404 . The flexural extension of torsion spring  425  may be sufficient to allow detent roller  427  to clear a detent slot  428  in detent member  412  yet insufficient to clear trapping slot  426  in valve retainer  404 . The flexural extension may be altered or adjusted as desired for a particular application. In the exemplary embodiment shown, since there are two detent positions in each detent member, the poppet assemblies may be biased in two positions. The detent positions may be sufficiently shallow to allow the detent rollers to ramp out of them when the actuating spring force is sufficiently high by means of a wedging action. Accordingly, the valve release occurs when the force of the shifting means overcomes the force of the restraining means. The action of this mechanism is referred to as a spring biased, over-the-center mechanical release, and may be described as “snap action” and “over-the-center.” 
      Alternatively, the mechanical release described can be modified into a trigger type mechanical release. This may accomplished by allowing torsion spring  425  to make contact with end cap  350 . As a piston advances, torsion spring  425  will be increasingly flattened, eventually arriving at the point where detent member  420  is released. Accordingly, the valve actuation is triggered at a specific location during the piston stroke, when physical interference restrains an energy source biased toward shifting. Since such a release mechanism requires contact by definition, a mechanical release may be duplicated on the opposite side of a piston as well as the side shown. The exemplary valve release mechanisms described above utilize the piston advance for accumulating energy to shift a valve. However, valve release mechanisms other than those described may be used.  
      Fixed onto case  196  is a position detector  431  such as a reed switch with signal wires  430 . Fixed into piston member  401  is a position transmitter  429  such as a magnet. A signal from detector  431  can be used for purposes including starting and stopping the fluid motor by means of a solenoid valve, controlling the fluid motor speed, counting strokes, computing the flow rate, and totalizing the flow.  
      In use, a pressurized, powering fluid flows into a piston of a motor through inlet port  180  (shown in  FIG. 4 ), passageway  184  (shown in  FIG. 4 ) and inlet piston tube  194 . Inlet piston tube  194  may be fixed in end cap  350 . Tube  194  may slidably engage piston tube chamber  206  (shown in  FIG. 4 ) and may be isolated from variable volume chamber  212  by a seal assembly, such as the seal assembly comprised of seal  202  (shown in  FIG. 4 ), seal bushing  190  (shown in  FIG. 4 ), and seal retainer  200  (shown in  FIG. 4 ). Fluid may exit tube  194  to enter chamber  206  (shown in  FIG. 4 ) and continue through passageway  240  (shown in  FIG. 4 ) into inlet distribution chamber  416 . Fluid may enter piston chamber  204  from distribution chamber  416  through holes  408  in spool  415 . Fluid in chamber  204  may be blocked from an alternative exit by poppet  417 . Likewise, fluid entering chamber  204  may be blocked from exiting by poppet  409 . Thus, fluid entering chamber  204  may be used to displace a piston assembly in direction  370 . As the piston assembly advances in direction  370 , it displaces fluid in piston chamber  212 . The fluid being displaced may exit chamber  212  through holes  408  in spool  405  into outlet chamber  407 . From chamber  407 , the fluid may continue through passageway  208  (shown in  FIG. 5 ) into piston tube chamber  207  (shown in  FIG. 5 ), into piston tube  195 , into passageway  183  (shown in  FIG. 5 ), and finally through outlet  182  (shown in  FIG. 5 ). Fluid in chamber  204  may be blocked from an alternative exit by poppet  417 .  
      Where a fluid powered proportioning pump makes one complete cycle (i.e., a complete stroke in both directions), the proportioning accuracy may be substantially maintained. However, if highly accurate proportioning should be maintained and the cycle is not complete, then additional design details may be incorporated to achieve even increased accuracy. In order to keep the proportioning substantially accurate, the system may be modified to either (1) make the ratio substantially constant in each stroke direction, or (2) make the displacement substantially constant in each stroke direction. One example of a way to make the displacement substantially constant in both directions is to extend the pump shaft through a seal in the pump end cap and extend the motor shaft through a seal in the motor end cap in a way to insure the swept area on both sides of a piston are the same. Another example of a way to make the displacement substantially constant is to make the ratio substantially constant in each stroke direction using carefully chosen cross sections for shaft  118 , inlet piston tube  194 , and outlet piston tube  195 . One example for determining the ratio is set forth below. The following equations assume a 1 to 5 proportion of fluid pump displacement to fluid motor displacement. The ratio is chosen for exemplary purposes only, and it should be apparent that other, different ratios could also be used. A ratio of 1 to 5 is a typical ratio for post mix beverages. The actual ratio will be dependent on the application requirements.  
           (     A   -   F     )       (     C   -   E     )       =     1   5         
         A     (     C   -   F     )       =     1   5         
 
 Where A is the area of a pump piston, F is the area of a shaft connecting a pump piston and motor piston, C is the area of a motor piston, and E is the summed area of the inlet piston tube and the outlet piston tube. 
 
       FIG. 7  shows a front cross section of the exemplary fluid motor of the device of  FIG. 6  looking away from the fluid pump. The motor housing may be comprised of case  196 , inlet port tube  180 , outlet port tube  182 , and fasteners  224 . Shaft  118  may be fixed to piston member  400 . A multi-port valve assembly may include valve retainers  403 , rack member  411 , gear  414 , spring mount  96 , and spring  100 . Passageway  432  may provide communication between chamber  204  and holes  408  of spool  415  and spool  405 .  
       FIG. 8  shows a front cross section of the exemplary fluid motor of the device of  FIG. 6  looking toward the fluid pump. The motor housing may be comprised of case  196  and fasteners  224 . Also visible are pump inlet port tube  162  and outlet port tube  236 . Inlet tube  162  may communicate with inlet chamber  375 . Likewise, outlet tube  236  may communicate with outlet chamber  376 . Pump fasteners  192  are visible on the interior surface of motor end cap  121 . However, any fasteners could be used. Shaft  118  may slidably pierce motor end cap  121  though seal retainer  191 .  
       FIG. 9  shows a top view cross section of an exemplary end port motor combined with an exemplary shaft-less, adjustable displacement pump in one embodiment of the present invention. A fluid motor piston may be comprised of piston member  324  and piston member  323 , may contain a multi-port valve, and may be fixed together by a fastener  328 . The operation of an exemplary multi-port valve within a fluid motor piston that causes a reciprocating motion by the flow of a powering fluid has been described in detail above. The exemplary multi-port valve may include the following features that are shown: magnet  94 , spring  100 , magnet spring carrier  97 , valve member  106 , valve member  107 , spring  98 , magnet spring carrier  96 , passageway  222 , passageway  218 , chamber  61 , and chamber  142 . Other valves may used as would be apparent to one skilled in the art.  
      Tube  304  may be slidably positioned with respect to end cap  310  to achieve the desired, adjustable pump displacement and then fixed in position by screwing in jam nut  306  that compresses o-ring  308  providing a static seal and locking tube  304  in position by friction. When a piston travels in direction  325  and while the tip of pump tube  304  is past seal  316  on the side of chamber  318 , the interior volume of chamber  318  may be increasing as pump tube  304  is withdrawn. The increased volume of chamber  318  may be filled with a pumped fluid drawn into pump inlet barb fitting  300  through one way check valve  302  and through the interior of pump tube  304  into pump chamber  318 . Pump chamber  318  may be isolated from fluid motor chamber  212  by a seal assembly. An appropriate exemplary seal assembly may comprise of seal bushing  314 , seal ring  316 , and seal retainer  312 . In use, as a piston travels in direction  326 , a pumped fluid is displaced from pump chamber  318  by the intrusion of tube  304 . The only path open to the displaced pump fluid is through check valve  320  since flow in the opposite direction is blocked by check valve  302 . Pumped fluid exits pump chamber  318  through one way check valve  320  and into passageway  329  that communicates with inlet piston tube chamber  206  (not shown). A pumped fluid mixes with a powering fluid in chamber  206  (not shown). The reciprocating motion of a piston causes a pumped fluid to enter a device of the present invention and mix with a powering fluid in an adjustable proportion. The adjustable pumping feature is associated with the tip of tube  304  clearing a seal  316  on the side of motor chamber  212 . This is possible because tube  304  may be positioned where the tip of tube  304  is within pump chamber  318  for only a portion of a reciprocating stroke of a motor piston rather than its entire stroke. Positioning tube  304  further into the fluid motor in direction  325  increases the pumped volume per piston stroke while positioning tube  304  further out of the fluid motor in direction  326  decreases the pumped volume per piston stroke. Consider a piston stroke where the tip of tube  304  is within pump chamber  318  for part of a piston stroke in direction  325 . Beginning with the tip of tube  304  within pump chamber  318 , a pumped fluid enters chamber  318  through tube  304  to replace the volume of tube  304  that is withdrawn. However, as the stroke continues, the tip of tube  304  clears seal  316  and pump chamber  318  is in communication with motor chamber  212  and the flow of a pumped fluid ceases for the remainder of the stroke. Fluid flows through check valve  320  only from chamber  318  to passageway  329  because a pump is designed to create a pressure greater than a motor inlet pressure when tube  304  is within chamber  318  and advancing in direction  325 . Otherwise, there is no flow through check valve  320  because the pressure is always higher on the passageway  329  side of check valve  320  in communication with inlet piston tube chamber  206  (not shown). When a piston reverses to travel in direction  326 , the tip of tube  304  approaches seal retainer  312 . Retainer  312  has a leading bevel to guide in the tip of tube  304 . The tip of tube  304  is rounded to facilitate entry. As the stroke continues, the tip of tube  304  passes seal  316  and enters chamber  318  to function as previously described displacing a portion of the volume of chamber  318 . The embodiment of this invention allows a first powering fluid to adjustably proportion and pump a second pumped fluid. Furthermore, with a piston of sufficiently large cross section, additional pump sets may be incorporated into a fluid motor allowing a powering fluid to proportion and pump multiple pumped fluids. Another embodiment allows pumps with pump tubes  304  of different diameters to achieve more or less displacement per stroke. It is a substantial advantage of this invention that it combines simplicity with great versatility.  
      It will be apparent to those skilled in the art that various modifications and variations can be made to the structure and methodology described herein. Thus, it should be understood that the invention is not limited to the examples discussed in the specification. Rather, the present invention is intended to cover modifications and variations.