Pressure testing pump

Abstract: The hand lever actuated pump for testing a water line for leaks by pumping water into the line under pressure comprises a container (12) for water to be pumped and a hand lever (16) actuated piston and cylinder type pump (14) having suction and discharge strokes in response to displacement of the hand lever (16) in opposite directions about a lever axis (138). The piston and cylinder components (54, 50) of the pump (14) are pivotally supported on the container (12) and interconnected with the hand lever (16) so as to provide a high flow rate during the initial part of the discharge stroke and a progressively increasing leverage for displacing the piston (54) during the discharge stroke to provide high pressure discharge at the end of the discharge stroke with a low force application to the hand lever (16).

Description: Background of the Invention This invention relates to the art of pumps and, more particularly, to manually operated pumps for testing fluid lines under pressure for leaks. It is of course well known to test lines in a fluid system such as a hydraulic or water supply system for leaks following installation of the system or the repair of lines therein. The use of manually operated lever type fluid pumps for such testing is likewise well known. Such pumps generally include a container for fluid to be pumped into the system to be tested, and a hand lever actuated piston and cylinder type pump having suction and discharge strokes in response to displacement of the operating lever in opposite directions about a lever axis. The inlet side of the pump is in flow communication with fluid in the container, and the discharge side of the pump is provided with a hose or the like which is adapted to be coupled with the system for delivering fluid thereto from the pump. The system to be tested is initially filled with fluid, and the lever is then displaced in opposite directions about its pivot axis to pump additional fluid into the system until the desired test pressure is attained which may, for example, be 50 bar or 725 psi. Generally, the pump includes a pressure gauge for indicating the system pressure and for determining the presence or absence of leaks in that the system pressure should not fall during the test period if there are no leaks. In pressure testing pumps of the foregoing character heretofore available the hand lever is pivotally mounted on the container at one end thereof and extends to the opposite end of the container, the pump cylinder is fixed relative to the container, and the piston rod of the pump piston is pivotally attached to the hand lever at a location spaced from the pivot axis for the lever. In DE-C-1 303 067 which concerns a hydraulic extractor there is disclosed a manually operated pump of the type defined in the precharacterizing portion of independent claim 1 having a hand lever pivotally mounted on a container and having a fixed cylinder in which a piston is arranged which has a piston rod pivotally connected to the hand lever. Pulling up on the hand lever displaces the piston in the cylinder to provide the suction stroke, and pushing down on the hand lever displaces the piston to provide the discharge stroke. The location of the pivot axis for the piston rod relative to the pivot axis for the lever, the size of the piston and the length of the hand lever are variables which cooperatively determine the per stroke volume displacement capability for the pump and the leverage available for displacing the piston during the discharge stroke. High volume flow is desired to minimize the number of strokes and thus the work required by the operator in using the test pump, and good leverage is desired during the discharge stroke, and especially as the test pressure is approached, to enable attaining a high test pressure and to minimize the physical force required to be applied to the lever by the operator as the system pressure increases. For a given size piston in the pumps heretofore available, initial pumping of additional fluid into the system can be achieved with a full stroke displacement of the hand lever which may, for example, be an angular displacement of about 80° to 90° or more about the lever axis. As the test pressure is approached, however, it is necessary because of the location of the pivot axis for the piston rod relative to the lever axis to limit the stroke of the hand lever to less than about 30° in order for the operator to physically displace the hand lever to displace the piston and thus fluid into the system at or near the test pressure. At lever angle greater than about 30°, it is either impossible for the average operator to apply sufficient force to displace the piston, or it is impossible to move the piston because of the side thrust imposed thereon by the lever-piston rod relationship. Even with a short stroke of 30° or less, the test pumps heretofore available require a force on the hand lever of from about 445 to 623 N (100 to 140 pounds) to achieve piston displacement at a test pressure of 50 bar or 725 psi. Thus, operation of the pump as the test pressure is approached is both difficult and requires undesirably high physical exertion by the operator. If the piston rod connection is moved closer to the lever axis and/or the diameter of the piston is reduced, either or both of which will increase the available leverage, the volume displacement capability is reduced, whereby more strokes are required to attain the test pressure and, thus, more time is required to test a system with very little if any reduction in the overall physical exertion required of the operator. In order to optimize the available leverage, the operating end of the hand lever extends beyond the corresponding end of the container for the liquid. While this increases the leverage, such a lever extension is potentially hazardous. In this respect, as the system pressure increases and a greater force application to the end of the lever is required to discharge fluid from the pump, the downward force applied to the end of the lever at a point beyond the end of the container can cause the container to tilt about the latter end thereof. Such instability can cause liquid to spill from the container, subjects the operator to potential injury, and subjects the component parts of the pump to potential damage. Summary of the Invention It is accordingly an object of the present invention to provide a pressure testing pump having improved operating and performance characteristics and which pump is operable to pump fluid under high pressure into a system being tested with less lever force than heretofore required to thereby minimize or overcome the foregoing disadvantages of such pumps heretofore available. To achieve these objects there is provided in accordance with the invention a pump for pressure testing a fluid system comprising container means for fluid to be pumped into said system, cylinder means having inlet means in flow communication with fluid in said container means and outlet means for delivering fluid to said system, piston means reciprocable in said cylinder means and including piston rod means, lever means supported on said container means for pivotal displacement about a lever axis, one of said piston rod means and said cylinder means being connected to said lever means at a first pivot axis, whereby pivotal displacement of said lever means in opposite directions about said lever axis relatively reciprocates said piston means and said cylinder means in opposite directions through suction and discharge strokes, and valve means for controlling the flow of fluid through said inlet means and outlet means of said cylinder means in response to said relative reciprocation between said piston means and said cylinder means, characterized in that the other of said piston rod means and said cylinder means is connected to said container means at a second pivot axis, whereby pivotal displacement of said lever means in opposite directions about said lever axis simultaneously pivotally displaces said piston rod means and said cylinder means in opposite directions about said second pivot axis for progressively increasing the leverage with respect to displacement of said piston means during said discharge stroke. More particularly in this respect, a pressure testing pump according to the present invention provides a progressively increasing leverage for displacement of the pump piston during the discharge stroke so as to optimize the leverage and considerably reduce the lever force heretofore required to displace the piston during the discharge stroke, especially as the test pressure is approached and finally reached. At the same time, a pump according to the invention achieves the latter advantage without sacrificing the per stroke volume displacement capability of the pump. Moreover, a pressure testing pump in accordance with the present invention enables the pump piston to be displaced by the lever during the discharge stroke, at a test pressure of 50 bar or 725 psi, with an angular displacement of the lever considerably greater than heretofore possible and, at the same time, through the use of a force on the lever substantially less than heretofore required to displace the lever through an angle of 30° or less at the same test pressure. Preferably, the variable leverage by which the foregoing advantages are realized is achieved through a relatively pivotal interrelationship with respect to the mounting of the piston and cylinder pump and operating lever on the container for the fluid to be pumped. More particularly in this respect, the cylinder of the piston and cylinder pump is supported for pivotal displacement relative to the container, and the lever is pivotally mounted on the container and pivotally interconnected with the piston rod of the pump piston in a manner whereby displacement of the lever in opposite directions about its pivot axis reciprocates the piston in opposite directions in the cylinder to provide the suction and discharge strokes thereof and simultaneously pivots the piston and cylinder unit about the cylinder pivot axis. At the end of the discharge stroke the pivot axis between the lever and piston rod is generally coplanar with the lever axis and cylinder pivot axis and, during the suction stroke, the axis between the piston rod and lever pivots about the lever axis and along an arcuate path toward the cylinder pivot axis. Accordingly, during the ensuing discharge stroke the pivot axis between the piston rod and lever moves along the arcuate path back toward the coplanar relationship with the lever axis and the cylinder pivot axis. This displacement of the piston rod axis progressively increases the leverage on the pump piston during the discharge stroke. The pivotal interrelationship between the piston and cylinder pump and the lever advantageously enables the discharge of fluid from the cylinder at a high test pressure through a larger angular displacement of the lever than heretofore possible and, at the same time with less force on the lever than heretofore required with respect to the same test pressure. These advantages are due in part to the fact that the pivotal relationship referred to minimizes the application of side thrust between the piston rod and cylinder and thus between the piston and cylinder during the discharge stroke, thus enhancing the ease with which the piston can be displaced by the lever. It will be appreciated of course that the volume of fluid displaced also varies during the discharge stroke and progressively decreases from a high volume displacement at the beginning of the discharge stroke to a smaller volume as the lever approaches the end of the discharge stroke. However, the overall volume of fluid displaced during the full discharge stroke is comparable to that of the test pumps heretofore available, and the larger angular displacement capability of the lever at a high test pressure compensates for the progressively decreasing volume of flow and enables a volume of flow as the test pressure is approached which is comparable to that of the test pumps heretofore available. The pump according to the invention enhances the ease with which the piston can be displaced by the lever to pump fluid under high pressure into a system being tested with an angular displacement of the lever larger than heretofore possible and, at the same time, with a lever force considerably less than heretofore required to displace the piston against the same system pressure and through a much smaller angular displacement. Further, the pump of the foregoing character is structurally simple and economical to construct, is efficient in operation and requires less physical exertion on the part of an operator with respect to raising the pressure in a system being tested to a given test pressure, and which can be operated at high test pressures without subjecting the operator to potential injury or the pump to potential damage as the result of instability of the pump. Brief Description of the Drawings The foregoing objects, and others, will in part be obvious and in part pointed out more fully hereinafter in conjunction with the written description of a preferred embodiment of the invention illustrated in the accompanying drawings in which: FIGURE 1 is a plan view of a test pump in accordance with the present invention; FIGURE 2 is a side elevation view of the test pump; FIGURE 3 is a sectional elevation view taken along line 3-3 in FIGURE 1 showing the component parts of the pump in their relative positions at the end of the discharge stroke; FIGURE 4 is a sectional elevation view similar to FIGURE 3 and showing the component parts of the pump in their relative positions at the end of the suction stroke; FIGURE 5 is a cross-sectional elevation view taken along line 5-5 in FIGURE 2; FIGURE 6 is an elevation view, partially in section, taken along line 6-6 in FIGURE 1 and showing the manifold arrangement for the discharge line, pressure gauge and dump valve; and, FIGURE 7 is an enlarged detail view in section showing the flow control valve arrangement for the discharge side of the piston-cylinder pump. Description of a Preferred Embodiment Referring now in greater detail to the drawings, wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the invention, a test pump 10 in accordance with the present invention includes a container 12 for fluid to be pumped into a system to be tested, a piston-cylinder type pump 14 for pumping liquid from the container into a system to be tested, and a hand lever 16 for operating pump 14 as described in greater detail hereinafter. Container 12 is preferably constructed of suitable plastic material and has a bottom wall 18, opposite side walls 20 and 22, and front and rear walls 24 and 26, respectively. Preferably, side walls 20 and 22 are provided with stiffening ribs 28, and the container has an upper edge defined by a peripherally continuous flange 30 which is configured to provide a ledge 32 extending outwardly of the corresponding one of the front, rear and side walls of the container. The portion of ledge 32 extending across front wall 24 and along a portion of side walls 20 and 22 extending rearwardly from the front wall supports a mounting plate 34 on which pump 14 and lever 16 are mounted as set forth more fully hereinafter. The inner end of support plate 34 is provided with a downwardly extending flange 36, and the support plate is mounted on container 12 by means of a pair of tabs 38 on the front end of the mounting plate which extend through slots 40 therefor in flange 30 and a pair of nut and bolt assemblies 42 extending through ledge 32 and plate 34 adjacent flange 36 thereof. As best shown in FIGURE 5, pump 14 is mounted on the underside of support plate 34 by means of a U-shaped bracket 44 having a base 45 secured to plate 34 such as by welding and spaced apart mounting plates 46 and 48 extending downwardly from base 45. Pump 14 includes a cylinder 50 having an axis 52, and a coaxial piston 54 attached to the lower end of a coaxial piston rod 56 by which piston 54 is axially reciprocated in cylinder 50 as set forth more fully hereinafter. Piston 54 is provided with an annular seal 58 and an annular bronze guide ring 60, and piston rod 56 extends upwardly through a bushing 62 at the upper end of cylinder 50 and is guided and sealed relative to cylinder 50 by an annular rod seal 64 and bronze guide ring 66. Cylinder 50 is received between mounting plates 46 and 48 of mounting bracket 44 and is supported thereon for pivotal displacement in opposite directions about a cylinder pivot axis 68 extending between side walls 20 and 22 of container 12 and transverse to cylinder axis 52. More particularly in this respect, cylinder 50 is provided with diametrically opposed passageways 70 and 72 coaxial with pivot axis 68 and opening to the interior of the cylinder and which passageways receive the threaded inner ends of a coupling member 74 and 76, respectively. As will be appreciated from FIGURE 5 and, from FIGURE 7 which shows coupling 76, couplings 74 and 76 have shoulders 78 received in an opening 80 in the corresponding one of the mounting plates 46 and 48 of mounting bracket 44, whereby cylinder 50 and thus pump 14 is pivotal relative to mounting bracket 44 and container 12 about cylinder pivot axis 68. If desired, a bearing sleeve, not shown, can be interposed between coupling shoulder 78 and opening 80. Passageway 70 provides an inlet opening to cylinder 50, and coupling 74 is an inlet coupling by which the inlet side of pump 14 is connected in fluid flow communication with fluid F in container 12. For this purpose, a hose or the like 82 is connected to coupling 74 and has an inlet end 82a at the bottom of container 12. If desired, the inlet end of the house can be provided with a suitable filter, not shown. Similarly, passageway 72 provides an outlet opening from cylinder 50 and coupling 76 provides an outlet coupling by which fluid is discharged from the cylinder, as explained more fully hereinafter. As will be appreciated from FIGURE 7, inlet and outlet couplings 74 and 76 are each provided with a replaceable, one-way valve cartridge 86 having an inlet end 88, a discharge end 90 and a slidable valve sleeve 92 biased by a spring 94 to close inlet end 88. Cartridge 86 is received in a chamber 96 in couplings 74 and 76, which chamber has an opening 97 at one end thereof, and the cartridge is removably retained in chamber 96 by an apertured threaded retaining plug 98 at the opposite end of the chamber. It will be appreciated, of course, that cartridge 86 is oriented in coupling 76 so as to permit fluid flow out of cylinder 50 and, accordingly is reversibly oriented in coupling 74 so as to permit fluid flow into cylinder 50. It will likewise be appreciated that displacement of piston 54 downwardly in cylinder 50 from the position thereof shown in FIGURES 3 and 5 to the position shown in FIGURE 4 provides a suction stroke by which fluid is drawn into cylinder 50 from container 12 through inlet coupling 74, and that displacement of the piston upwardly in cylinder 50 from the position shown in FIGURE 4 back to the position shown in FIGURES 3 and 5 provides a discharge stroke by which the fluid in cylinder 50 is displaced therefrom through outlet coupling 76. As best seen in FIGURES 5 and 6, outlet coupling 76 is connected to the inlet side of a distribution manifold 100 by a flexible hose 102. Manifold 100 is supported beneath support plate 34 by means of a normally closed fluid return or dump valve 104 which is mounted on plate 34 by means of a nut 106 and which has an operating knob 108 for opening and closing a valve outlet 110 for the purpose set forth hereinafter. Manifold 100 supports a pressure gauge 112 in an opening 114 therefor in support plate 34, and a fluid discharge line 116 is connected to manifold 100 and has an outlet end, not shown, provided with a suitable coupling by which the discharge line is connected to a fluid system to be tested. During the discharge stroke of the pump piston, fluid flows through line 102 to manifold 100 and thence through discharge line 116 into the system being tested, and the fluid pressure in the system at any given time during the test is registered by pressure gauge 112. At the conclusion of a test, knob 108 of valve 104 is displaced to open the latter valve, whereby fluid pumped into the system is returned to container 12 through valve outlet 110. Lever 16 is pivotally mounted on the upper side of support plate 34 and is pivotally interconnected with the upper end of piston rod 56 so as to displace piston 54 in opposite directions in cylinder 50 in response to pivotal displacement of the lever in opposite directions about its pivot axis. More particularly in this respect, lever 16 which is preferably of tubular, folded sheet metal construction has a front end 16a and a rear end 16b provided with a suitable hand grip 120. The folded sheet metal construction provides for front end 16a to have a pair of spaced apart parallel lever plates 122 and 124 by which the lever is pivotally mounted on support plate 34 and pivotally interconnected with piston rod 54. Lever 16 is pivotally mounted on support plate 34 by means of a U-shaped mounting bracket 126 having a base 128 secured to support plate 34 such as by welding and a pair of upwardly extending legs 130 and 132. The lower ends of lever plates 122 and 124 are respectively inwardly adjacent legs 130 and 132 and are pivotally secured thereto by corresponding pivot pins 134 which provide a lever pivot axis 138 spaced above and parallel to cylinder pivot axis 68. Piston rod 56 extends upwardly through a slot 57 provided therefor in support plate 34 and bases 45 and 128 of mounting brackets 44 and 126 and upper end 56a of the piston rod is threadedly interconnected with a sleeve 140, transverse to the sleeve axis. Sleeve 140 is received between the upper ends of lever plates 122 and 124 and is pivotally interconnected therewith by means of a pin 142. Pin 142 provides a piston rod pivot axis 146 which is parallel to cylinder pivot axis 68 and which is spaced above and parallel to lever pivot axis 138. Lever 16 is shown in FIGURES 2 and 3 in a first position which is the position of the lever at the end of the discharge stroke of the pump and, thus, at the beginning of the suction stroke. A stop plate 148, which can be integral with lever mounting bracket 126, is positioned to engage the lower edges of lever plates 122 and 124 to limit displacement of lever 16 in the direction of the discharge stroke of the pump. In FIGURE 4, lever 16 is in its second position which is the position of the lever at the end of the suction stroke and, thus, at the beginning of the discharge stroke. As best seen in FIGURES 1 and 2, rear end 16b of lever 16 is provided with a cross pin 150, and rear wall 26 of container 12 is provided with a pivotal wire latch 152 having an upper end 154 adapted to engage over pin 150 when the lever is in the position shown in FIGURE 2. This latch arrangement facilitates using the lever as a handle for carrying the test pump. In operation, container 12 is filled to a suitable level with system fluid to be pumped into a system to be tested and which system fluid can be water, hydraulic fluid, ethylene glycol, kerosene and other heating oils, and the like. The system is initially filled with system fluid, and the outlet end of discharge hose 116 is connected to a test port of the system. Lever 16 is then pivoted counterclockwise about lever axis 138 from the first lever position shown in FIGURES 2 and 3 to the position shown in FIGURE 4 which, as will be appreciated from FIGURES 3 and 4, amounts to an angular displacement of lever 16 of about 80°. As will be appreciated from the positions of the component parts in FIGURES 3 and 4, this pivotal displacement of lever 16 displaces piston 54 downwardly in cylinder 50 and, simultaneously, pivots pump 14 counterclockwise about cylinder pivot axis 68. Downward displacement of piston 54 in cylinder 50 provides the intake or suction stroke for the pump whereby, during such displacement, fluid in container 12 is drawn into cylinder 50 through hose 82 and inlet coupling 74. Pivotal displacement of lever 16 clockwise about lever axis 138 from the second lever position shown in FIGURE 4 to the first position shown in FIGURES 2 and 3 displaces piston 54 upwardly in cylinder 50 and, simultaneously, pivots pump 14 clockwise about cylinder pivot axis 68. Displacement of piston 54 upwardly in cylinder 50 from the position shown in FIGURE 4 to the position shown in FIGURE 3 provides the discharge stroke for the pump whereby, during such displacement, fluid in cylinder 50 is discharged through outlet coupling 76 and line 102 to manifold 100 and thence through line 116 into the system to which the test pump is coupled. The system pressure following the discharge stroke is registered by pressure gauge 112. As the test pressure is approached, the suction and discharge strokes are shortened by pivoting lever 16 through a smaller angular displacement from its first position than the full displacement of 80°. This assures that the discharge strokes at high pressures are achieved with an optimum application of force on the lever by the operator. Accordingly, it will be understood that reference hereinafter to a discharge stroke of the lever in degrees is with respect to the angular displacement of the lever from its first position at the beginning of the discharge stroke. It is to be noted at this point that the pivotal mounting and pivotal interrelationship between pump 14 and lever 16 provides for a variable volume of flow during the discharge stroke of the pump and a variable leverage for displacement of the pump piston during the discharge stroke and which leverage progressively increases as the lever and thus the pump piston approach the end of the discharge stroke. More particularly in this respect, as will be appreciated from the positions of the component parts shown in FIGURE 3, when lever 16 is in its first position at the beginning of the suction stroke and at the end of the discharge stroke piston rod pivot axis 146, cylinder pivot axis 68 and lever pivot axis 138 are substantially coplanar, whereby a downward force on end 16b of lever 16 translates into a substantially axial force upwardly on piston rod 56 and thus piston 54 in the direction of the discharge stroke. As lever 16 is pivoted counterclockwise about lever axis 138 to the position shown in FIGURE 4, and thus through the suction stroke for the pump, piston rod pivot axis 146 pivots counterclockwise about lever axis 138 and moves progressively along an arcuate path toward cylinder pivot axis 68. During this movement of the lever, piston 54 is displaced downwardly in cylinder 50 and, as will be appreciated from the lever arm defined by axes 138 and 146, the rate of downward displacement of piston 54 progressively increases, whereby the volume of fluid flow into cylinder 50 progressively increases during the suction stroke. When the component parts reach the position thereof shown in FIGURE 4, which are the positions of the component parts at the end of the suction stroke and the beginning of the discharge stroke, the lever arm defined by axes 138 and 146 provides the least amount of leverage with respect to displacing piston 54 during the ensuing discharge stroke. When lever 16 is pivoted clockwise from the position shown in FIGURE 4, the component parts move through the discharge stroke from the positions shown in FIGURE 4 back towards the positions thereof shown in FIGURE 3 and, during the discharge stroke, rod pivot axis 146 pivots clockwise about lever axis 138 and progressively along the arcuate path away from cylinder pivot axis 68 back toward the substantially coplanar relationship with axes 68 and 138 shown in FIGURE 3. It will be appreciated, therefore, that the leverage for displacing the pump piston progressively increases during the discharge stroke and is optimized when the component parts again reach the positions shown in FIGURE 3. Also during the discharge stroke, the rate of displacement of piston 54 upwardly in cylinder 50 progressively decreases, whereby the volume of fluid flow progressively decreases during the discharge stroke. Accordingly, with respect to a full stroke displacement of lever 16 and piston 54 during the discharge stroke, the discharge stroke begins with a high volume displacement of fluid from cylinder 50 and a moderate leverage for displacing the piston and ends with a low volume fluid displacement and optimum leverage with respect to displacing the piston. It is to be noted at this point with respect to the substantially coplanar relationship referred to herein with respect to axes 68, 138 and 146 in the first position of lever 16, that lever axis 138 is intentionally offset slightly rearwardly of the plane through axes 68 and 146 when lever 16 engages stop 148 to preclude the piston rod from moving to an over center position relative to axis 138 which would cause piston 54 to suck fluid into cylinder 50 and the end of the discharge stroke and thus discharge fluid at the beginning of the ensuing suction stroke. Therefore, the term substantially coplanar reflects such an offset. At the same time, it will be appreciated that the axes could be coplanar in the first position of the handle, it simply being preferred to assure against the undesired suction at the end of the discharge stroke. Therefore, the term substantially coplanar as used herein is intended to include a planar relationship between the three axes. In connection with testing a system, the pump according to the present invention advantageously enables the initial pumping of additional fluid into the system quickly and with a minimum number of full strokes of lever 16 and, as the test pressure is approached, enables the fluid toe be pumped into the system with considerably less force on lever 16 than heretofore required and, thus, with considerably less physical effort on the part of the operator. The foregoing advantages are best appreciated with reference to a comparison between the pump according to the preferred embodiment illustrated and described herein and a pump of comparable dimensions and of the structure of previously available pumps in which the pump cylinder is fixed relative to the container and the piston rod is pivotally connected to the lever at a location between the pivot axis for the lever and the opposite or operating end of the lever. In a pump of the latter structure having a lever length of about 63.3 centimeters or 24.92 inches, a piston diameter of about 2.98 centimeters or 1.18 inches, and a pivotal connection between the piston rod and lever at a distance of about 7.42 centimeters or 2.92 inches in the direction from the lever pivot axis towards the opposite end of the lever, displacement of the lever through a discharge stroke of just 20° requires a force on the operating end of the lever of more than 579 N (130 pounds) when the system test pressure is 50 bar or 725 psi. At the same test pressure, a force of more than 556 N (125 pounds) on the lever is required to displace the piston through a discharge stroke of about 10°. In contrast, a pump according to the preferred embodiment having a lever length from lever axis 138 to the opposite end of the lever of about 54.38 centimeters or 21.41 inches, a lever arm length between axes 138 and 146 of about 6 centimeters or 2.36 inches and a piston diameter of about 3.48 centimeters or 1.37 inches is adapted to pump fluid at a system pressure of 50 bar or 725 psi through a discharge stroke of 20° with a force on the operating end of the lever of less than 177 N (40 pounds), and is adapted to pump fluid at the same system pressure through a discharge stroke of 10° with a lever force of about 133 N (30 pounds). Furthermore, the pump according to the present invention is adapted to pump fluid at the foregoing test pressure through a discharge stroke of the lever between about 55° to 60° with a lever force of between 378 and 400 N (85 and 90 pounds), through a discharge stroke of the lever of about 40° with a lever force of between 289 to 311 (65 to 70 pounds), and through a lever discharge stroke of about 30° with a handle force of between about 244 to 266 N (55 to 60 pounds). These figures indicate that, at a given system pressure, the leverage for displacing the piston in the direction of the discharge stroke of the pump increases as the piston approaches the end of the discharge stroke. Still further, the pump of the preferred embodiment has a per stroke fluid displacement capacity comparable to that of the prior art pump, and the prior art pump cannot be operated at a test pressure of 50 bar or 725 psi with a lever discharge stroke of 30° or more. Moreover, it will be clearly appreciated from the foregoing figures that the pump of the present invention can be operated, without excessive physical exertion by the operator, to deliver fluid under pressure into a system being tested at pressures in excess of 50 bar or 725 psi. While considerable emphasis has been placed herein on the structures of and the structural interrelationships between the component parts of the preferred embodiment, it will be appreciated that other embodiments of the invention can be made and that many changes can be made in the preferred embodiment without departing from the principals of the present invention. In particular, it will be appreciated that the fluid inlet and outlet flow paths for the cylinder do not have to be coaxial with the pivotal mounting thereof. Further, any suitable one-way valve, such as a spring biased check valve, can be used to control the flow of fluid into and from the cylinder, and the one-way valves could be provided in the inlet and outlet lines at locations other than those shown in the preferred embodiment. Still further, it will be appreciated that the dimensions referred to hereinabove with regard to the preferred embodiment, and the preferred substantially coplanar relationship between the cylinder, piston rod and lever axes, can be varied without affecting the structural interrelationship between the component parts which provides for the variable displacement and variable leverage features by which the improved operating and performance characteristics are attained in accordance with the present invention. Moreover, while hand lever operation is preferred, it will be appreciated that the lever could be foot operated, in which case a biasing spring would be provided to bias the lever from the first toward the second position thereof.

Claims: A pump for pressure testing a fluid system comprising container means (12) for fluid to be pumped into said system, cylinder means (50) having inlet means in flow communication with fluid in said container means (12) and outlet means for delivering fluid to said system, piston means (54) reciprocable in said cylinder means (50) and including piston rod means (56), lever means (16) supported on said container means (12) for pivotal displacement about a lever axis (138), one of said piston rod means (56) and said cylinder means (50) being connected to said lever means (16) at a first pivot axis (146), whereby pivotal displacement of said lever means (16) in opposite directions about said lever axis (138) relatively reciprocates said piston means (54) and said cylinder means (50) in opposite directions through suction and discharge strokes, and valve means (86) for controlling the flow of fluid through said inlet means and outlet means of said cylinder means (50) in response to said relative reciprocation between said piston means (54) and said cylinder means (50), characterized in that the other of said piston rod means (56) and said cylinder means (50) is connected to said container means (12) at a second pivot axis (68), whereby pivotal displacement of said lever means (16) in opposite directions about said lever axis (138) simultaneously pivotally displaces said piston rod means (56) and said cylinder means (50) in opposite directions about said second pivot axis (68) for progressively increasing the leverage with respect to displacement of said piston means (54) during said discharge stroke. Pump according to claim 1, characterized in that the piston rod means (56) is connected to said lever means (16) at said first pivot axis (146) and said cylinder means (50) is connected to said container means (12) at said second pivot axis (68). Pump according to claim 1, characterized in that said lever means (16) has first and second positions, displacement of said lever means (16) from said first toward said second position displacing said piston means (54) through said suction stroke to cause fluid in said container means (12) to flow into said cylinder means (50), displacement of said lever means (16) from said second toward said first position displacing said piston means (54) through said discharge stroke to cause fluid to flow from said cylinder means (50). Pump according to claim 3, characterized in that said first pivot axis (146), said lever axis (138) and said second pivot axis (68) are in generally coplanar relationship in said first position of said lever means (16), said first pivot axis (146) pivots about said lever pivot axis (138) and toward said second pivot axis (68) during displacement of said lever means (16) from said first to said second position, and displacement of said lever means (16) from said second toward said first position displaces said first pivot axis (146) back toward said coplanar relationship, whereby the leverage for displacing said piston means (54) progressively increases during said discharge stroke. Pump according to claim 4, characterized in that said lever axis (138) is between said first pivot axis (146) and said second pivot axis (68) when said lever means (16) is in said first position. Pump according to claim 2, characterized in that said second pivot axis (68) and said lever axis (138) are fixed relative to said container means (12) and said first pivot axis (146) moves in opposite directions along an arcuate path toward said second pivot axis (68) and away therefrom during pivotal displacement of said lever means (16) in opposite directions about said lever axis (138). Pump according to any one of claims 2 to 6, characterized in that said inlet means and said outlet means of said cylinder means (50) are coaxial with said second pivot axis (68). Pump according to any one of claims 2 to 7, characterized in that said container means (12) has upper edge means, support plate means (34) on said upper edge means and having outer and inner sides with respect to said container means (12), said lever means (16) being pivotally mounted on said outer side of said support plate means (34), said cylinder means (50) being pivotally mounted on said inner side of said support plate means (34), said piston rod means (56) extending from said cylinder means (50) through an opening (57) in said supports plate means (34) and having an end (56a) pivotally connected to said lever means (16) at said first pivot axis (146). Pump according to any one of claims 2 to 8, characterized in that said first pivot axis (146) is spaced outwardly from said lever axis (138). Pump according to claim 8, characterized in that said support plate means (34) is removably mounted on said container means (12). Pump according to any one of claims 1 to 10, characterized in that said fluid inlet and outlet means for said cylinder means (50) include inlet and outlet passageway means (70, 72) coaxial with said second pivot axis (68). Pump according to claim 11, characterized in that said valve means includes one way valve means (86) coaxial with each said inlet and outlet passageway means (70,72). Pump according to claim 8, characterized in that said support plate means (34) includes on its inner side a pair of mounting plates (46, 48) spaced apart and transverse to said second pivot axis (68), said cylinder means (50) being between said mounting plates (46, 48), said fluid inlet and outlet means including inlet and outlet openings (70, 72) in said cylinder means (50) coaxial with said second pivot axis (68), that inlet and outlet coupling means (74, 76) extend through opening means (80) in said mounting plates (46, 48) and respectively into said inlet and outlet openings (70, 72) in said cylinder means (50), said coupling means (74, 76) being pivotal in said opening means (80) in said mounting plates (46, 48) and supporting said cylinder means (50) for pivotal displacement about said second pivot axis (68), and that inlet and outlet line means (82, 116) are respectively connected to said inlet and outlet coupling means (74, 76).

Inventors: BEELEN VALERE HUBERT JACQUES, BEELEN, VALERE HUBERT JACQUES
Applicants: EMERSON ELECTRIC CO, EMERSON ELECTRIC CO.
Application year: 1993
Main classification: F04B9
IPC codes: F04B9, F04B3, F04B23, F04B13, F04B19