Patent Publication Number: US-2003223882-A1

Title: Flow measurement and control system for positive displacement pumps

Description:
[0001] This application claims the benefit of U.S. Provisional Application Serial No. 60/383,572 filed on May 28, 2002. 
    
    
     
       TECHNICAL FIELD OF THE INVENTION  
       [0002] This invention relates to the process and oil industries and to chemical injection; in particular the device relates to positive displacement or diaphragm injection-type pumps providing a means for monitoring and controlling the output flow.  
       BACKGROUND OF THE INVENTION  
       [0003] In the oil, gas, petrochemical, water treatment, and environmental protection industries there is an absolute necessity to treat many flowing liquids on a continuous basis with various chemicals. For example, a few of these chemicals are corrosion inhibitors, emulsifiers, scale inhibitors, antifreeze, bactericides, and others. Many of the flowing liquids are flowing under pressure within pipelines and require a high-pressure means of injecting the chemicals. In many cases, the quantity of injected chemical is somewhat critical and must be adjusted from time-to-time to conform to the flow rate within the pipeline.  
       [0004] Many injection sites for chemicals are remote from maintenance personnel, which creates a dilemma since the injector pumps are, by nature, prone to unexpected failure. In the oil and gas industry for instance, an interruption of chemical treatment can mean the shut-in of a well or freeze-up of a transmission line. Such events can cost many tens-of-thousands of dollars.  
       [0005] Currently, the best method of protecting against injector pump failure is through a daily visit by pump maintenance personnel (known as a pumper). Many chemical injection locations are at oil well pumping sites that may be remote from the pumper by a hundred miles or more. Offshore production requires a boat and crew to assist the pumper in making his rounds to dozens of unmanned platforms. This type of service is very costly. Even with daily visits by a pumper, there is no assurance that the pump will not fail within minutes after the inspection is completed.  
       [0006] Typically, pump failures are caused by malfunctions of the suction or delivery check valve, packing leakage, mechanical drive failure, chemical supply blockage, electrical or gas interruption to the drive motor, or piping failures, just to name a few.  
       [0007] For the past fifty years or more, there has been a serious problem in the industry due to the inability to constantly monitor the flow rate of the chemical injection pumps. The problem has always been, how to detect, measure, and possibly adjust, the flow rate of a chemical injector from a distant location.  
       [0008] With the development of reliable cellular telephone service, it is now possible to provide communication between the pumper and the pump installation, both onshore and offshore, with the ordinary cellular telephone (or other SCADA—supervisory control and data acquisition system). If a simple and inexpensive method of automatically monitoring of injection flow rates was available, the monitoring system would transmit an appropriate signal to the maintenance personnel through the cellular system or SCADA system, and industry could save millions of dollars each year.  
       [0009] There have been many attempts made to monitor flow rates of chemical pumps and transmit this data, but none have been successful. Typically, these systems are so expensive and complicated that more problems are created than solved. The most common technique is by sensing the pressure in the output of the injection pump. There are several techniques, well known in the industry, to monitor pressure ranging from simple “snap-like” devices (high-normal-low pressure switches) to pressure transducers/transmitters. A typical application of a pressure transmitter system may be found in the disclosure by Smith et al. (U.S. Pat. No. 5,654,504) that, although the application is not for an injection pump, discloses a Downhole Pump Monitoring System that supervises a pump by using a pressure transmitter to determine if the pump is operating.  
       [0010] Yoder et al. (U.S. Pat. Nos. 6,135,719 and 6,135,724) disclose a more typical injection pump system. Here a complex feedback control scheme is used to meter and monitor a series of chemical injection pumps by means of position control on the stroke control unit.  
       [0011] Therefore there is a need in industry for a simple, foolproof and inexpensive “tell-tail” device that will monitor the output of a chemical injection pump and give an indication that flow is entering the system that is being protected by the pump and operate in conjunction with an inexpensive SCADA system that may readily provide monitoring and control of a remote chemical injection pump is still required by industry.  
       SUMMARY OF THE INVENTION  
       [0012] The present invention provides the missing link (“tell-tale”) for the notification process that a positive displacement pump is, or is not, delivering fluid into the line. The instant device is based about a simple differential pressure flow switch. It is known that a positive displacement pump is, in itself, a meter to measure delivery volume. Such a pump includes a plunger of a fixed diameter, a fixed stroke length and a constant stroking rate. Therefore, each stroke of the pump should deliver a fixed volume of liquid. Problems, such as check valve leakage, packing leakage, air leakage in suction piping, or partial blockage of the suction piping, can create a condition where partial, or no chemical delivery, even though the pump is mechanically operating, can occur.  
       [0013] The device makes it possible to determine what percentage of the fixed delivery stroke is actually delivering chemical, and the associated monitoring and control systems quantifies this percentage to the pumper.  
       [0014] The “tell-tale” device is a mechanical differential pressure switch specifically placed in the discharge line of the positive displacement pump that compares the pump discharge pressure with the pressure of the line into which chemical injection is desired. It is known that if a positive displacement pump is delivering fluid then the pressure within the pump must exceed the line pressure.  
       [0015] The actual mechanical device utilizes the discharge poppet (or check valve) in a positive displacement pump. If fluid is exiting the pump, then the poppet valve must lift: the instant device monitors the movement of outlet check valve (or poppet). The device can be built into the pump or it may be a stand-alone valve added to the discharge port of the pump. A standard discharge check valve is modified so that the mechanical motion of the valve may be monitored. The standard poppet has a pin added to the valve. The pin is brought out of the valve body through a sealing means and the movement of the pin is monitored.  
       [0016] If the pin moves a reasonable amount (several thousandths of an inch) then the valve is opening and fluid is flowing from the pump into the system. If pin does not move, within a reasonable period of time, then the fluid cannot be flowing into the system. In the simplest form, a magnetic (proximity) switch monitors the pin movement and a timer/monitor system monitors the time period. An alarm is transmitted if the poppet does not move within a specified time period.  
       [0017] The associated flow control device, on the other hand is a variable volume chamber also connected to the discharge port of a positive displacement pump. The chamber volume may be varied from, essentially, zero to the same volume (or greater) that the pump is capable of delivering. Thus, if the chamber is set at zero, then the entire contents of the pump chamber will be sent into the line. If the variable chamber is set at (or greater) than the volume of the pump chamber, then the discharge fluid is diverted into the variable chamber and no fluid is injected into the line. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0018] Figure One is a cut-away illustration of the prototype mechanical indicating poppet (check) valve.  
     [0019] Figure Two is an isometric view of the preferred production mechanical indicating (poppet) check valve.  
     [0020] Figure Three is a side view of the preferred production indicating check valve showing a completely assembled unit with a side mounted magnetic (proximity) switch.  
     [0021] Figure Four is a side view of the preferred production unit showing how the movement of the mechanical pin (poppet pin) is transferred to a side-mounted magnetic switch.  
     [0022] Figure Five is a top view of Figure Four.  
     [0023] Figure Six is a cut-a-way illustration of an alternate embodiment for the poppet seal.  
     [0024] Figure Seven is a system drawing showing the interconnection and interaction of the control and monitoring system. (Note the prototype mechanical limit switch shown on top of the indicating check valve.)  
     [0025] Figure Eight is a cut-away illustration of the variable volume chamber.  
     [0026] Figure Nine illustrates a mechanical indicating poppet (check) valve used directly within the body of a pump.  
     [0027] Figure Ten is a typical set of pump characteristics. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0028] It is known that positive displacement (PD) pumps are, in themselves, a meter to measure delivery volume. A PD pump includes a plunger of a fixed diameter, a fixed stroke length, and a constant stroking rate. Therefore, each stroke of the pump should deliver a fixed volume of liquid. Such problems as check valve leakage, packing leakage, air leakage in the suction piping, or partial blockage of the suction piping can create a condition of partial or no chemical delivery even though the pump is mechanically operating.  
     [0029] The instant device makes it possible to determine what percentage of the fixed delivery stroke is actually delivering chemical, and the associated control and monitoring system quantifies this percentage to the user.  
     [0030] As shown in FIGS. 1 through 5, the device,  1 , used to determine the percentages of each delivery stroke of the pump, is a simple mechanical differential pressure switch. In order to introduce chemical into the pipeline, the pressure within the pump must exceed the pipeline pressure by a few pounds per square inch. When this occurs, a sealing poppet,  13 , which also serves as the discharge check valve, is lifted a short distance (on the order of 0.040″). Basically the check valve is acting as a differential pressure sensor—it will lift (or unseat) only when there is a positive differential pressure across the valve. This motion is transferred by the pin,  14 , to a switch, mounted externally to the device. The prototype uses an external mechanical switch,  2 , mounted at the end of the plunger (see FIG. 7); whereas the preferred device uses a standard off-the-shelf proximity switch,  20 , mounted to the side of the unit. It is possible to use internal Hall-Effect type switches to sense the motion of the poppet thereby producing a sealed unit. The choices are up to the manufacturer.  
     [0031] The key to the invention is the use of the output check valve on a pump to sense positive differential pressure across the valve and using the mechanical motion of the check valve to provide an indication of positive differential pressure or flow out of the pump.  
     [0032] The switch,  20  or  2 , in turn, starts a timer, which measures in milliseconds. At the end of the pump discharge stroke, the poppet reseats, due to the suction phase of the cycle, and stops the timer. The timer stops after each discharge stroke and the final duration of a fraction of a second reveals the percentage of the stroke that delivered liquid into the pipeline. At the end of each suction stroke the timer is automatically reset to zero.  
     [0033] For instance, if a pump strokes at  35  strokes per minute, which is typical, the total cycle is one complete stroke in 1.71 seconds. Assuming a linear pump action, the delivery stroke would be one-half of the stroke time or 0.857 seconds (857 milliseconds). When the count stops at the end of the discharge stroke, there is an approximate duration of 0.8 seconds for the count to be monitored by the user or pumper viewing a meter at the pump site, or by the system that transmits the count to a remote location by cell phone or SCADA link. At the end of each count cycle, the timer is automatically reset to zero. For the ease of operation, the actual count can be visually monitored at the pump location and/or transmitted by a communication signal. The count is in hundreds-of a-second, i.e.,  86  for full flow,  43  for half-flow, or ( 0 ) for no flow. A flow chart (FIG. 10) is supplied which allows the direct correlation of all timer counts to corresponding flow delivery.  
     [0034]FIG. 10 has been shown with a ½-inch plunger at  35  strokes per minute, which was the system used in the prototype. The remainder of table can be filled in by any person skilled in the art by careful measure of flow and timing.  
     [0035] In one embodiment, it is anticipated that the signal will sent over the telephone as a voice, which actually verbalizes the count once every 1.7 seconds. Once the means for determining the pump flow rate from a remote location is available, it is relatively easy to readjust this pumping rate over the telephone.  
     [0036] This readjustment is created by a variable chamber device,  6 , (see FIG. 8) connected directly into the pump chamber, which precedes the discharge check valve,  1 , as shown in FIG. 7. The variable chamber device,  6 , through a double floating piston,  65  and  66 , and an adjustable stop screw,  64 , allows a portion of the liquid on the discharge stroke to flow into the volume chamber until the floating piston,  66 , is stopped by the adjustable screw, 64. (As shown in FIG. 7 the adjustable screw,  64 , is directly connected to a motorized controller, 7.) At this instant the chemical begins to exit the discharge check valve,  1 , that activates the differential pressure flow switch,  2 , (or if the production model is used  20 ) and the injection time is monitored by the timer.  
     [0037] To adjust the flow rate over the telephone, a designated dial key is depressed and held. A motor,  7 , driving the adjustment screw moves the screw to a new position that the relative movement of the floating piston,  69 , is changed. Each 1.7 seconds the pump will announce the new flow rate back to the user or the pumper. In a similar manner a SCADA system may remotely set the pump flow.  
     [0038] The volume adjustment motor,  7 , is rotated forward or reverse by depressing a designated telephone key, for instance, depressing key “3” increases flow, depressing key “4” decreases flow. The user (or pumper) would increase or decrease flow and monitor the flow rate. Once the desired flow is obtained the user would stop making the up/down adjustment. A SCADA system would be similar.  
     [0039] The system described is for an electrically driven pump. A somewhat different system will be needed for gas driven pumps often found on unattended offshore platforms and land locations. A gas driven pump has a fixed plunger size and fixed stroke length but has a variable stroke time. Again, the basis for measuring the flow rate will rely upon the instant device with some differences in the flow rate calculation. It should be remembered that even if the electrical or gas-driven pump is operating it might be delivering partial or no chemical flow to the line.  
     [0040] The instant device is able to monitor the actual chemical delivery and immediately notify the pumper by telephone (or the SCADA network) if the delivery deviates between set limits or totally ceases to flow. At any time the pumper (or user) can remotely access the pump and instantly determine, or even change, the pumping rate.  
     [0041] The preferred embodiment for the indication check valve is shown in FIGS. 2 through 5, and the preferred embodiment for the variable volume chamber is shown in FIG. 8. The preferred indicating check valve (production model) consists of seven major parts. The cover,  10 , which protects various parts attached to the top plate,  11 . The upper body,  12 , which screws onto the lower body,  17 , and which contains the poppet assembly,  13 . A proximity switch,  20  and a shim  18 , which translates the motion of the poppet assembly so that the motion may be sensed by the magnetic proximity switch.  
     [0042] The top plate,  11 , is screwed to the upper body,  12 , and servers to hold the magnetic proximity switch,  20 , the shim,  18 , the shim alignment pins,  22   a  and  22   b . The poppet pin,  14 , passes through and aperture,  24 , in the top plate and through a corresponding aperture in the upper body,  34 , thereby coming to rest against the shim,  18 . The shim is held in place by a shim screw or bolt,  19 , which screws into a corresponding aperture in the top plate. The two alignment pins ( 22 ) serve to keep the shim aligned over the proximity switch,  20 , which screws into a corresponding aperture in the top plate. Naturally there would be corresponding alignment pin apertures bored in the top plate.  
     [0043] The top plate,  11 , is secured to the upper body by securing bolt,  21 , which passes through an aperture in top plate and into a bolt hole or aperture,  35 , drilled in the upper body,  12 . A top plate alignment pin,  23 , is located opposite the top plate securing bolt and on its underside. This pin passes into a corresponding aperture on the upper body,  33 , and assures that the top plate and the upper body align and that the poppet pin,  14 , can freely move through the associated apertures coming to rest on the underside of the shim,  18 . A cover,  10  screws onto the upper plate at threads  29  and protects all the (otherwise exposed) parts located on the upper plate. The cover  10  is placed on the unit after the top plate,  11 , which is of necessity manufactured of aluminum, is attached to the upper body,  12 . (Aluminum is required because magnetic sensing of poppet movement is employed—if another means were employed then the top plate could be manufactured from another material.)  
     [0044] The shim,  18 , serves to translate the motion of the poppet pin,  14 , over to the end of the proximity switch, 20. As stated earlier, the poppet (and naturally the pin) is expected to move by approximately 40-thousandths of an inch. This motion will be “amplified” by the shim (lever principal) and thus the movement of the poppet (going open) will be sensed by the proximity switch. It should be noted that larger (or even smaller) motions of a mechanical check might occur and that that motion (or movement) will be determined by the size of the pump and output check valve. Thus the dimension given is for purposes of illustration only.  
     [0045] As can be seen, the upper body,  12  screws into the lower body,  17 . The lower body accepts the upper body and also the poppet assembly,  13 . The poppet assembly consists of a poppet (or valve),  16 , a poppet pin,  14 , which is secured into the valve, and a spring,  15 . This is a standard check valve BUT FOR the poppet pin,  14 . Associated with the valve are a spring lip,  41 , and O-ring groove,  42 , and an O-ring,  49 . The poppet pin is sealed by standard techniques, i.e., a Teflon washer,  45 , and an O-ring,  46 . The sealing means is held in place by a spring washer,  47 , against which the poppet spring,  15 , rests when the complete device is fully assembled. Fluid enters through the inlet port,  39 , and exhausts through the outlet port,  38 . In addition an O-ring,  40  and associated groove  48  are provided in the upper body to ensure a liquid tight seal between the two body parts. Preferably the body parts are made from stainless steel; however, operating conditions and chemicals may set a different requirement for wetted parts.  
     [0046]FIG. 6 shows an alternate seal system for the poppet wherein the O-ring/Groove seal is replaced with a ball and seal. The O-ring and Groove,  49  and  42 , is replaced with a ball,  43  and seat  44 . Actually any reasonable seal means may be used with the poppet valve—the preferred ring and groove, the alternate ball and seat, or even a needle. It is possible to use other metal-to-metal seals and the inventor envisions the use of such alternates.  
     [0047]FIGS. 1 through 6 show embodiments of the indicating check valve manufactured as a separate assembly for installation on a pump. It should be apparent that the concept could be employed directly within the body of a pump as shown in FIG. 9. In this case the standard outlet check valve is replaced with the instant device,  1 . Like the preferred embodiment that uses a lower body (see item  17  in FIGS.  1 - 6 ), the device has an outer plug,  92  (identical to the upper body—item  12  in FIGS.  1 - 6 ) that screws into the pump body,  104 . The poppet assembly,  93 , has a poppet indicating pin,  94 , a poppet spring,  95 , a poppet valve,  96 , along with a sealing means (O-ring and groove, 91) and a seal,  97 , where the poppet pin,  94 , penetrates the outer plug, 92. Fluid flows from the pump piston chamber through the pump outlet conduit (essentially the passage from the piston chamber) to the outlet,  102 , being controlled by the instant device, 1. Thus, the outlet conduit or the outlet port on a pump may serve as the “lower” body for the instant device. In fact it is possible with pumps to replace the standard outlet check valve with instant device (without its lower body) thereby using the existing check valve seat as a set for the instant device.  
     [0048] Not shown in FIG. 9 is an indicating switch means; however, a system similar to the preferred embodiment may be used. A mechanical switch may be mounted directly over the indicating pin,  94 . This is a simple design choice. The designer must remember that the indicating pin,  94 , and switch should be protected from the elements, the chance of physical damage, etc. Again, simple design choices. Identified in FIG. 9 are stand pump parts, such as the inlet,  101 , the inlet check valve,  100 , the inlet check valve retaining nut,  105 , and the pump piston,  103 . The pump chamber is immediately above the pump piston.  
     [0049] The associated variable volume cylinder is shown in FIG. 8, and, like the body parts ( 12  and  17 ), the wetted parts are made from stainless steel. However, operating conditions and chemicals may set a different requirement for wetted parts. The cylinder consists of six basic parts. The cylinder liner,  73 , the cylinder top,  60 , the cylinder bottom,  62 , the floating pistons,  65  and  66 ), the adjustment screw,  64 , and the cylinder wall,  61 , (which may be eliminated through careful manufacturing choices if the cylinder liner,  73 , is bound between the cylinder top and bottom). Note, two floating pistons,  65  and  66  are shown and it is possible to use a single piston. The double piston arrangement is for operating safety and is not a limitation on the volume chamber.  
     [0050] In addition to the major parts in the variable volume cylinder, the first piston,  65 , is spring loaded by a spring,  67 , and has at least one O-ring,  71 , and associated O-ring groove,  69 , and moves within the cylinder liner,  73 . The second piston,  66 , is free to move within the cylinder liner,  73 . The second piston has an O-ring,  72 , and associated O-ring groove,  70 .  
     [0051] The variable volume cylinder is attached to the outlet port of a pump via the inlet-outlet port,  63 . The device is shown, in FIG. 7, connected in parallel with the indicating check valve,  1 . Fluid from the pump flows from the outlet to the check valve and the variable volume. The fluid flows into the variable volume chamber until the piston(s) are stopped by the adjustment screw. Fluid then flows into the check valve and when the pressure is sufficient the check valve lifts thereby allowing fluid to flow into the pipeline (or other equipment that is being protected). At the top of the pump stroke, the check valve closes and, since the pipeline pressure is now higher than the fluid pressure coming from the pump, the check valve remains closed and fluid flows from the volume chamber into the pump. On the next stroke the process is repeated. Thus the variable volume chamber sets the fluid flow from the pump.  
     [0052] As shown in FIG. 7, the variable volume cylinder is attached to motorized driver,  7 , which drives the adjustment screw,  64 . Thus, as shown in FIG. 7, the indicating check valve and the variable volume cylinder, when associated with standard electronics will provide “tell-tale” indication of flow/no-flow and flow control. As stated earlier, the tell-tail indicating check valve may be connected directly to a delay circuit that makes certain the tell-tail operates each time within the pump stroke period. If the tell-tail fails to move, then the pump is not operating and an alarm would be sent to the user (pumper).  
     [0053] There has been disclosed a system for monitoring flow (tell-tale) from a positive displacement pump and for controlling the volume of flow. The tell-tale device may be used in two modes, 1) pure tell-tale—if the poppet does not lift within a reasonable time period and alarm will be generated, and 2) flow monitoring and alarm—the lift time is monitored, compared to a table (based on the pump) and output flow determined. In addition a volume control device has been disclosed thereby making a complete control and monitoring system. The system may communicate remotely by telephone, SCADA or other communication system.  
     [0054] The prototype tell-tale device uses a mechanical switch,  2 , whereas the industrial preferred device uses a proximity switch,  20 , but all that is necessary a technique for determining the position (open/closed) of the poppet valve; thus, Hall-Effect devices, other proximity switches, pressure sensitive solid state devices, and the like all fall within the scope of this disclosure. In fact the sensing means for determining position may be incorporated within the upper body ( 12  of FIGS.  1 - 6  or  92  in FIG. 9) of the indicating check valve, thereby eliminating the poppet pin and the seals. Such a concept is within this disclosure.  
     [0055] Materials used for the manufacture of the device should not be construed as a limitation but only as an example. Similarly the example dimensions given should not serve as a limitation and a fluid driver may be used in place of the electric driver,  7 , (see FIG. 7).  
     [0056] The preferred device has been described as a stand-alone unit; however, as disclosed, the indicating check valve may be directly incorporated into a pump body as a direct replacement for the standard outlet check valve. It is the intention of the inventor to claim this use of his indicating check valve as set out in the claims. The device has been described for use with PD pumps, but will serve equally well with diaphragm pumps and other similar types of pumps. Hence the term pump as used in the claims should be broadly construed.  
     [0057] Item Listing  
     [0058] This list is provided to aid the Examiner in the examination of this application and may be included in the disclosure at the discretion of the Examiner. Some of these items may not appear in the drawings or the specification.  
                                                      1.   In general the “tell-tail” device           2.   Mechanical indicating switch           3.           6.   In general the volume chamber           7.   Motorized Volume Adjuster           8.           10.   Cover           11.   Top Plate           12.   Upper Body           13.   In general the Poppet           14.   Poppet (Indicating) Pin           15.   Poppet Spring           16.   Poppet Valve           17.   Lower Body           18.   Shim (Transfer Bar)           19.   Shim Securing Bolt           20.   Magnetic Switch (preferred)           21.   Top Plate Securing Bolt           22.   Shim Alignment Pins (a and b)           23.   Top Plate Alignment Pin           24.   Top Plate Poppet Plunger Aperture           25.   Shim Alignment Pin Apertures (a and b)           26.   Top Plate Alignment Pin Aperture           27.   Top Plate Securing Aperture           28.   Shim Securing Bolt Aperture           29.   Top Plate to Cap Threads           30.   Cap to Top Plate Threads           31.           32.           33.   Upper Body (to Top Plate)               Alignment Aperture                       34.   Upper Body Poppet Pin Aperture           35.   Top Plate Securing Bolt Hole               (in Upper Body)           36.   Upper Body Threads           37.   Lower Body Threads           38.   Outlet Port           39.   Inlet Port           40.   Body O-ring Seal Groove           41.   Poppet Spring Lip           42.   Poppet O-ring Groove           43.   Poppet Ball           44.   Body Seat           45.   Poppet Pin Washer           46.   Poppet O-ring           47.   Poppet Spring Washer           48.   Body O-ring           49.   Poppet O-ring           60.   Cylinder Top           61.   Cylinder Wall           62.   Cylinder Bottom           63.   Volume Inlet-Outlet Port           64.   Volume Adjustment (or Jack) Screw           65.   Volume First Piston           66.   Volume Second Piston           69.   Volume First Piston O-ring Groove           70.   Volume Second Piston O-ring Groove           71.   First Piston O-ring           72.   Second Piston O-ring           73.   Cylinder Liner           90.           91.   Poppet O-ring           92.   Upper Body (pump embodiment)           93.   In general the poppet           94.   Poppet Pin           95.   Poppet Spring           96.   Poppet Valve           97.   Poppet Spring Washer           98.   Body O-ring           99.   Poppet Seals           100.   Pump Inlet Check Valve           101.   Pump Inlet           102.   Pump Outlet           103.   Pump Piston           104.   Pump Body           105.   Pump Inlet Check Valve Retainer           106.