US3485176A - Pumping system - Google Patents

Description

Dec. 23, 1969 ao. TELFQRD ET AL 3,485,176

PUMPING SYSTEM Filed April 28. 3,96',` 5 Sheets-Sheet l INVENTORS TTOK/VEVS DN" 23, 1959 ao.. TgLFQsp 5T AL 3,485,17@

LPUMLH@ File@ April 28, 11957 5 Shams-Sheet 2 fm wArf /59 /4/ INVENTORS F l -5 mmf a rame@ Y FMA/K 6. urr

Dec. 23, 1969 c. o. TELFoRD ET AL PUMPING SYSTEM med April 28 1967 WA TER 5 Sheets-Sheet 3 Fl/EL PIE-' P /sobr BY ffm/w( a. Bar/'1s MW #M ATMP/V656 3,485,176 PUMPING SYSTEM Carlyle 0. Telford and Frank G. Butts, Hayward, Calif.,

assignors to Malsbary Manufacturing Company, Oakland, Calif., a corporation of California Filed Apr. 2S, 1967, Ser. No. 634,639 lut. Cl. F0413 13/02, 19/06, 49/02 US. Cl. 103-9 7 Claims ABSTRACT F THE DISCLOSURE A high pressure intermittent demand hot water washing apparatus having a delivery line with a delivery valve at the end, a fuel burner heating a coil through which water is pumped, an unloader device for relieving the high back pressure in the apparatus upon closure of the delivery valve, and a safety interlocked fuel and water pumping system which positively interrupts the supply of fuel to the burner upon a drop in the water pressure. A continuously running water pump supplies the water to the heating coil, and a fuel pump which is physically dependent upon the output pressure of the water pump supplies the fuel to the burner. In three of the embodiments, the dependence is through a killer diaphragm in the fuel pump backed by the water pressure, and in two of the embodiments, the dependence is through a coupling means which reacts to the water pressure to couple mechanical power from the prime mover to the fuel pump.

BACKGROUND OF THE INVENTION This invention relates to a pumping system for water heating apparatus, and more particularly to an interlocked safety pumping system for supplying both water and fuel to the heating apparatus in response to both the availability and the demand for the water.

Such Water heating apparatus is used in steam cleaning machines, steam generators, industrial hot water heaters and in high pressure, high velocity hot water washing machines. In a typical machine of this type, water is supplied under pressure to a coil. The coil is heated by a burner tired by fluid fuel and the water is then delivered either in the form of steam or hot water at a high pressure to the user through a delivery apparatus such as a hand-held steam cleaning gun. Water is usually supplied to the coil at a relatively high pressure by a positive displacement pump.

SUMMARY OF THE INVENTION In the pumping system of the present invention, a uid fuel such as fuel oil is supplied to the burner by a reciprocating fuel pump whose pumping action is governed by the water pressure delivered from the water pump. In the absence of the appropriate water pressure, the action of the fuel pump is disabled, or killed, so that no fuel is pumped,

It is advantageous to leave the water pump running continuously so the apparatus may respond rapidly to demand. The pumping apparatus of the present invention therefore provides an unloader device which relieves the high back pressure created upon closure of the delivery valve in the delivery line by recirculating or bypassing the pumped Water at low pressure back to the water reservoir. To prevent waste of fuel in heating this recirculated water, the bypass is located upstream of the heating coil. As the coil is not being supplied with water during this unloaded phase of operation of the pumping apparatus, the burner is cut olf promptly to avoid overheating and consequent damage to the coil. For the same reason, supply of fuel to the burner is immediately cut off upon any failure in water supply, such as might occur due to the emptying of nited States Patent O ice a portable water tank. This prompt fuel cut oif is provided in the present invention by the killer device which disables the fuel pump. Reliable failsafe operation of the killer action is assured by making the fuel pumping physically dependent upon the water supply pressure, rather than upon any secondary sensing apparatus.

For further safety in the operation of the apparatus, the fuel supply line includes a quick-acting spring-loaded dilferential valve which requires buildup of fuel pressure in the fuel line to a predetermined level before opening to admit fuel to the burner. This assures clean ignition of the burner by providing the proper amount of fuel pressure before ignition and termination of the fuel supply to the burner upon any sharp drop in the fuel supply pressure, such as that due to the initiation of killing action in the fuel pump. Prompt and clean initiation and termination of the fuel supply to the burner may be seen to be of particular importance in relatively small portable water heating apparatus subject to repetitive demand and having little or no storage capacity for the heated water or steam. In such apparatus the burner must be turned on and olf practically in unison with the operation of the delivery valve, or the apparatus will rapidly overheat. Also, any tendency of the burner to fail to ignite all the fuel supplied to it because of 10W fuel supply pressure at either the beginning or the termination of ignition would be aggravated by the repeated start-stop action of the burner and would create a potential safety hazard through accumulation of unburned fuel. Accordingly, it is a principal object of the present invention to provide a pumping systern for pumping two different liquids, in which pumping of the second of said liquids is dependent upon pressure created by the first of said liquids being pumped.

Another object of the present invention is to provide a safety interlocked fuel and water supply system for a water heater having a heating coil red by a lluid fuel which positively prevents overheating and damage to the coil upon failure of the water supply by interfering with the pumping action of the fuel pump.

A further object of the present invention is to provide a safety pumping system for fuel and water supply to a water heater of the character described which immediately, reliably and cleanly terminates fuel supply to said heater upon termination of water supply to the coil of the heater.

Yet another object of the present invention is to provide a safety fuel and water pumping system of the character described in which fuel supply to said heater is cut off until the fuel supply pressure is suflicient to ensure proper ignition of the burner of said heater, and the Water supply pressure is at the desired level for supply to the coil.

Still another object of the present invention is to provide a safety fuel and water supply system of the character described in which the ratio of fuel pumped to water pumped may be conveniently adjusted.

A further object of the present invention is to provide a pumping system of the character described in which the fuel pump is disabled in the absence of a predetermined pressure of water supply from the water pump.

A still further object of the present invention is to provide a high pressure hot water washing apparatus having a safety pumping system of the character described and having a delivery valve in its delivery line, in which the fuel pump is rendered inoperative in response to the closing of the delivery valve.

Further objects and advantages of my invention will appear as the specification proceeds, and the new and useful features of the pumping system will be fully defined in the claims attached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred forms of my invention are illustrated in the accompanying drawings, forming part of this application, in which: l

FIGURE 1 is a schematic view of a high pressure hot water washing apparatus constructed in accordance with the present invention;

FIGURE 2 is a schematic View of a second embodiment ofthe pumping system of the present invention;

FIGURE 3 is a schematic view of another embodiment of the pumping system of the present invention;

FIGURE 4 is a schematic view of still another embodiment of the pumping system of the present invention; and

FIGURE 5 is a schematic view of yet another embodiment of the pumping system of the present invention.

While only the preferred forms of the present invention have been shown, it should be understood that various changes or modifications may be made within the scope of the claims attached hereto without departing from the spirit of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in detail, and more particularly to FIGURE 1, it will be seen that the pumping system 11 of the present invention is used with a Water heating apparatus 12 and includes a first pump 13 having walls 14 defining a pumping chamber 16 and a reciprocating element 17 formed for alternately increasing and decreasing the volume of the chamber 16 and coupling means 21 attached to the rst pump 13 and operable to disable pump 13 in the absence of an output pressure in a second pump 19 exceeding a certain limit.

The pumping chamber 16 is in fluid communication through an input conduit 46 with the source of fuel supply and through an output fuel supply line 32 with a burner 66. Input and output check valves 47 and 48, respectively, are connected to the chamber 16 to prevent backflow of pumped fuel. The second pump 19 communicates through an input conduit 53 with a water reservoir 75 and pumps water through an output conduit S4 to heating coil 74.

As here shown, pump 13 is a diaphragm pump, although other reciprocating, positive displacement pumps such as piston pumps may be used. Preferably, reciprocating element 17 takes the form of flexible diaphragm of oil resistant material such as silicone or synthetic rubber reinforced on both sides by load distributing plate members 22 and 23. Actuation of diaphragm 17 by drive means 18 is here accomplished through mechanical connection which includes rod member 26 reciprocated by drive means 18 and biased toward drive means 18 by a spring means 27 bearing on rod member 26 and the casing 28 of pump 13. Another spring means 29 is disposed in chamber 16 bearing on plate member 23 and one wall of chamber 16 to bias reciprocating element 17 toward drive means 18 for restoring the volume of chamber 16 upon movement of rod member 26 toward drive means 18. The amount of liquid pumped is determined by adjustment of the spacing.

In the form of the invention shown in FIG. 1, the pump 13 is disabled from pumping fuel by a killer element 31 which renders the reciprocation of diaphragm 17 ineffective to pump fuel. The killer 31 cooperates with walls 14 and reciprocating element 17 in delining the chamber 16, and is here shown as a flexible diaphragm which may be formed of materials similar to those used for reciprocating element 17. When not restrained by coupling means 21, killer member 31 will move essentially in unison with reciprocating element 17 to counteract and render ineifective the displacement or change in volume of chamber 16 induced by reciprocation of reciprocating element 17. Thus, when the killer member 31 is unrestrained by coupling means 21, not enough pressure is applied by reciprocating element 17 to the uid in chamber 16 to enable the fluid to overcome the back pressure imposed on fuel supply line 32 so that no fluid is pumped by pump 13.

Another load distributing plate member 34 is on the side of killer member 31 facing away from chamber 16. A spring means 36 is interposed between the plate member 34 and a movable pressure responsive element or piston 37 reciprocatable in a second chamber 38 formed by wall 14 and separated from chamber 16 by the killer member 31. Pressure responsive element 37 here comprises a flexible cup element 39, in movably sealing relation to the walls of a portion of housing 28, and a rod member 41 contacting cup element 39 and interposed between cup element 39 and spring means 36 for transmitting movement of cup element 39 to spring 36 for restraining killer member 31 against reciprocation. Alternatively, the cup element 39 could be eliminated and rod member 41 gasketed by an O-ring carried in a groove at its periphery.

The side of cup element 39 facing away from rod member 41 confronts a chamber 42 formed in housing 28 in uid communication via a conduit 43 with the output of pump 19, so that movable pressure responsible element 37 is repsonsive to the output pressure of pump 19. A stop means 44 is interposed in second chamber 38 to limit the motion of rod member 41 in compressing spring means 36, thereby limiting the pressure applied by spring means 36 to killer means 31 to regulate fuel supply pressure. Stop means 44 is formed as a collar 45 threadably engaged with the side walls of the second chamber 38 so that its axial position in the second chamber may be adjusted by rotating it. A lock ring 50 is provided to retain the collar 45 in position.

The pump 19 may be of any type appropriate to supplying water at a relatively high pressure, say on the order of 400 lbs/sq. in., and is here shown as a positive displacement diaphragm-type pump having a housing 49 which encloses a pumping chamber 51. One wall of chamber 51 is formed of a flexible diaphragm 52 which is reciprocated by eccentric drive means 18. Pumping chamber 51 is in uid communication with the inlet and outlet conduits 53 and 54 and is equipped with one-way check valves 56 and 57, respectively, to prevent backflow of the pumped fluid. Output conduit 54 is also connected to a cushion dome 58 downstream of output check valve 57 to smooth out the pulsations in the output of the pumped uid. The diaphragm 52 is coupled with the eccentric drive means 18 by a rod member 59 whose structure may be similar to that disclosed in U.S. Patent No. 2,873,687, issued Feb. 17, 1959, to C. L. Pritchard for a Diaphragm Pump. Cushion dome 58 may be of any appropriate structure for resiliently absorbing and rectifying the pulsations in the output of pump 19, and may take the form disclosed in U.S. Patent No. 2,808,070, issued Oct. 1, 1957, to W. F. Malsbary for Cushion Dome.

The differential valve 60 comprises a chamber 61 formed in a housing 62, and communicating with fuel supply line 32. A movable diaphragm 63 cuts olfV fluid communication of chamber 61 with an outlet conduit 64 leading to burner 66. Diaphragm 63 is biased toward chamber 61 to cut off uid flow by a spring 67 and its displacement is limited by a screw 68. When diaphragm 63 seals off chamber 61 from output conduit 64, only the area of diaphragm 63 corresponding to the cross section of chamber 61 which it confronts is exposed to the output pressure of fuel delivered on conduit 32 from pump 13. Once the pressure of the fuel delivered to chamber 61 by conduit 32 has become great enough to overcome spring 67 and move diaphragm 63 away from chamber 61 to open up the fluid communication of line 64, the greater area of diaphragm 63 is exposed to the fluid pressure in line 32 so that a lesser pressure is required to hold diaphragm 63 in this open position. This differential between the opening and closing pressures of the differential valve 60 ensures adequate fuel pressure for proper ignition of burner 66, and also assures that fuel will not be dribbled through to burner 66 should killer diaphragm 31 not completely counteract the movement of diaphragm 17, thereby permitting a slight output pressure of fuel in line 32.

The over-all high pressure hot water washing apparatus 12 includes a liquid delivery line 69 leading to a delivery valve 71 located in a hand-held gun 72 for aiming the stream of high pressure hot Water toward the apparatus to be washed. Pump 19 pumps water from the reservoir 75 through output conduit 54 to a check valve 73, through which the water is admitted to the heating coil 74. The water is there heated by the burner 66 and the current of air driven through the burner 66 by a blower 76 of the conventional type generally associated with oilfired burners. From the heating coil 74, the heated water flows out through the delivery line 69 to the gun 72 for use.

The check valve 73 includes a spring biased valve member 78 which blocks flow from output conduit 54 at pressures below a predetermined amount, such as 400 p.s.i. Above the predetermined pressure, valve member 78 opens to permit delivery of water from output conduit 54 to coil 74. Upstream of check valve 73, output conduit 54 also delivers water to the valve chamber 79 to unloader means 77, and also connects to conduit 43 leading to coupling means 21. A discharge line 81 is connected to unloader means 77 and leads back to Water reservoir 75.

In the unloader 77, a ball valve member 82 is disposed in chamber 79 and seats on a seat 83 to block ow from outlet conduit 54 to discharge line 81. A connector line 84 is connected to output conduit 54 downstream of valve member 78 to transmit the pressure on the downstream side of valve 73 to the pressure regulator 86 which forms a part of unloader means 77. Within pressure regulator 86 is a chamber 87 communicating with connector line 84 and closed on one side by a flexible cup member 88. Cup member 88 is disposed in movably sealing relation to the walls of chamber 87 and bears on a load distributing plate member 89 which in turn bears on a rod member 91. Rod member 91 extends toward ball valve member 82 and is capable upon movement of pushing ball valve member 82 up off of seat 83 to permit water to flow from outlet conduit 54 to discharge line 81. A spring 92 normally biases cup member 88 together with plate member 89 and rod member 91 away from the ball 82, but upon the exertion of sufficiently high pressure in connector line 84, such as pressure exceeding 400 p.s.i., rod member 91 is pushed toward ball 82 to move the ball off seat 83.

An additive pump 94 may be connected as a slave pump through a conduit 93 to the water pump 19 to add a detergent solution to the heated water in the manner shown in United States Patent No. 2,487,348 to I. F. Malsbary et al. and the co-pending U.S. patent application of Clarence L. Pritchard, Ser. No. 522,653, filed Jan. 24, 1966, entitled Washing Apparatus and assigned to the assignees of the present application.

The water level in the reservoir 75 may be automatically maintained by a conventional ffoat valve 114 connected to a water supply source such as a local hydrant (not shown). Conduit 32 and additive pump 94 are provided with suitable vent Valves 116 and 117, respectively, to facilitate priming the pumps 13 and 94.

Eccentric drive means 18 includes an eccentric crank shaft 118 journaled in casing 24 and rotated by suitable motor (not shown). Crank shaft 11S carries a ring bearing 119 attached to rod member 59 and having a mechanical connection 120 to rod member 26 for oscillating both rod members.

In operation of the apparatus shown in FIGURE 1, the motor which drives the eccentric drive means 18 is started so that pumps 13 and 19 begin to operate. If the manually operated delivery valve 71 in gun 72 is then opened, the water pump 19 will operate to pump water to check valve 73. After a predetermined pressure has built up upstream of check valve 73, such as, say, 400 p.s.i., the pressure on valve member 78 is sufficient to overcome the spring which biases it closed, and the check valve 73 opens to admit water to the heating coil 74.

While delivery valve 71 is open and water is being pumped by pump 19 into heating coil 74, a pressure in the neighborhood of 400 p.s.i. is communicated from outlet conduit 54 through conduit 43 to coupling means 21 where it acts on flexible cup element 39 to compress spring means 36 and thereby restrain killer diaphragm 31. As killer diaphragm 31 is restrained, the reciprocation of diaphragm 17 is effective to pump fuel from in- 4put conduit 46 out fuel supply line 32 toward burner 66. Pressure rapidly builds up in fuel supply line 32 to the point Where the resistance of the differential valve 60 is overcome and the differential valve opens to admit the fuel to an outlet conduit 64 leading to burner 66. At the burner 66, an igniter (not sho-wn) of any suitable type is used to ignite the fuel to heat the water in coil 74. The pressure in the neighborhood of 400 p.s.i. in outlet conduit 54 is also communicated on connector line 84 to chamber 87, Where it is insufficient to overcome the force of spring 92 to unseat ball 82.

When delivery valve 71 is closed, pressure builds up rapidly in output conduit 54, delivery line 69, heating coil 74 and connector line 84, as pump 19 is a positive displacement pump which runs continuously. This increasing back pressure would damage the system if it were not relieved by the action of unloading means 77. As the pressure builds up in connector line 84, it becomes great enough in chamber 87 communicating with line 84 to overcome the force spring 92 and move rod member 91 toward the ball 82 until it unseats the ball 82 from the seat 83. When this happens, the pressure in the outlet conduit 54 is relieved by discharging the pumped Water along the discharge line 81 back into the reservoir 75, and the check valve 73 closes.

When the unloader 77 opens, the pressure in outlet conduit 54 drops from the neighborhood of 400 p.s.i. to a much lower pressure which may be in the neighborhood of, say, 25 p.s.i. The pressure likewise falls in conduit 43 enabling spring 36 to move rod member 41 and exible cup element 39 away from killer diaphragm 31, thereby allowing spring 36 to expand and relieve the restraint on the killer diaphragm 31. The relieved killer diaphragm then oscillates in phase with diaphragm 17 to kill its pumping action. By this killing action, the pressure imposed in chamber 16 by the oscillation of diaphragm 17 may be reduced from the neighborhood of, say, p.s.i., to a pressure substantially below 40 p.s.i. so that the pressure in the fuel supply line 32 will no longer be sufficient to overcome the force of spring `67 in the differential valve 60. The differential valve will then snap closed to terminate the supply of fuel to burner 66.

Upon the operators reopening of delivery valve 71 in response to a new need for ho-t water, the pressure in delivery line `69, coil 74 and connector line 84 falls rapidly, so that the spring 92 may once again overcome the pressure in chamber 87 of unloader means 77 to move rod member 91 away from ball 82. Chamber 79 is so shaped and dimensioned that the ow of uid through the chamber and out discharge line 81 has a tendency to cause lball 82 to reseat on seat 83 in the absence of rod member 91, and thus cut off the flow in discharge line 81. When this flow is cut off, pressure rapidly builds back up again in outlet conduit 54 to the point ywhere it overcomes the force of the spring in check valve 73, opening that valve to supply water from the output conduit 54 to the heating coil 74 and on out delivery line 69.

The ranges of operating pressures for opening and closing of differential valve 60 are chosen to conform to the pressures of fuel pumped by pump 13 under unkilled and killed conditions, and may for example with the pressures of fuel supply suggested herein be set at an opening pressure of S p.s.i. and a closing pressure of 40 p.s.i. It may be seen that coupling apparatus 21 not only operates to disable fuel pump 13 when the water pressure in outlet conduit 54 drops due to the opening of the unloader means 77, but also upon failure of water supply to pump 19 from resrvoir 75, as pump 19 could not then generate the pressure to operate coupling means 21 to restrain killer diaphragm 31.

Turning now to FIGURE 2 there is shown an alternate embodiment of the pumping system of the present invention in schematic form. In this pumping system 11, two different liquids are pumped, one of which may be fuel for ring a burner such as :burner 66 in FIGURE l and the other of which may be water for supply to a heating coil such as coil 74 of FIGURE 1. The pumping system 11 includes a rst pump 121 having Walls 122 dening a pumping chamber 123 and a reciprocating element 124 which is formed for alternately increasing and decreasing the volume of chamber 123. A drive means 126 reciprocates a rod member 130 which in turn reciprocates element 124 to displace fluid within chamber 123. A sec-ond pump 127 is formed from walls 128 dening a chamber 129 separated from chamber 123 by a member 131 which may `be a flexible diaphragm similar to element 124. Member 131 is responsive to pressure in both chambers 123 and 129. When no fluid pressure is present in chamber 129, member 131 moves in phase with element 124 to cancel the displacement induced in the fluid contained in chamber 123 by the movement of element 124. It may thus be seen that member 131 serves as a coupling means responsive to the added pressure of the fluid in chamber 129 of pump 131 to operatively disable pump 121 when the pressure in chamber 129 falls below a predetermined limit. Reciprocating elements 124 and 131 may be exible diaphragms formed of material similar to diaphragms 17 and 31 shown in FIGURE l. The drive means may be constructed similarly to the eccentric drive means 18.

Pumps 121 and 127 are equipped with input check valves 132 and 133, respectively, and output check Valves 134 and 136, respectively, to prevent back ow through pumps 121 and 127. The output check valves 134 and 136 may be spring biased toward the closed position in a fashion similar to check valve 73 illustrated in FIGURE 1 to insure suicient back pressure in chambers 123 and 129 for proper operation of the pump, or other spring loaded check valves similar to check valve 73 and differential valve 60 illustrated in FIGURE 1 may be placed in the output conduits d-ownstream of the output check valves 134 and 136.

Member 131 is operatively connected to the second pump 127 by the pressure of fluid in chamber 129| so that member 131 is restrained against movement in response to element 124 when fluid is being pumped by the second pump 127. When no pressure is present in chamber 129, the displacement of member 131 in response to reciprocation of element 124 is sufficient to cancel the displacement induced by element 124 in a fashion similar to the killing action of killer member 31 of the embodiment shown in FIGURE 1, so that fluid is not pumped by pump 121. In the operation of pumps 121 and 127, member 131 is not held totally rigid by fluid pressure in chamber 129, so that some of the reciprocatory movement of element 124 is transmitted to member 131 to pump uid from chamber 129. While member 131 reciprocates somewhat to pump fluid from chamber 129 when fluid pressure is present in chamber 129, it in restrained against reciprocation to a degree that reciprocation of element 124 is able to impose enough pressure on fluid contained in chamber 123 to overcome the back pressure imposed on that chamber and pump the fluid out of that chamber. Chamber 123 of pump 121 is in iluid communication with input and output conduits 137 and 139, respectively, and chamber 129 of pump 127 is in fluid communication with input conduit 138 and output conduit 141.

The pumping system 11 as here shown could be substituted for the pumping system 11 depicted in FIGURE l, in which case the rst pump 121 would pump fuel to burner 66 along the output conduit 139 and the input conduit 137 would lead to a source of fuel such as a fuel tank (not shown). The second pump 127 would pump water to heating coil 74, and its input conduit 138 would be equivalent to input conduit 53 shown in FIGURE l. The output conduit 141 of pump 127 4would be coupled to the check valve 73 and the unloader 77 in the same fashion as output conduit 54 of FIGURE 1 is coupled to those valves, but conduit 43 would be eliminated, as the coupling of the pressure from the water pump to killer member 131 is performed internally of the pump apparatus.

Not only does the absence of fluid pressure in chamber 1219 cause member 131 to act in a fashion similar to killer diaphragm 31 of FIGURE 1, but the absence of fuel pressure from chamber 123 will prevent the reciprocation of element 124 from being transmitted to member 131 to pump the water. A double killing action is thereby provided in this embodiment of the pumping system, as no fuel will lbe pumped when the water pressure is absent, and likewise no water will be pumped when th-e fuel pressure is absent.

Another embodiment of the pumping system of the present invention is shown in FIGURE 3. In this embodiment, the pump 127 is constructed along the same lines as pump 127 shown in FIGURE 2 with the like numbered parts being equivalent, and the operation of second pump 127 is in all material respects the same as that depicted in FIGURE 2. Chamber 123 is similar to the chamber 123 in FIGURE 2 except that it has only one output conduit 142, which leads to a third pump 143.

The third pump 143 is formed of walls 144 defining third and fourth chambers 147 and 148, respectively, separated by a flexible diaphragm 146. The third chamber 147 communicates through the conduit 142 with chamber 123 and a hydraulic fluid such as brake fluid is sealed into chamber 123, conduit 142 and chamber 147 to transmit pressure impulses induced in chamber 123 by reciprocation of element 124 to diaphragm 146. In the same fashion as in the embodiment of FIGURE 2, in the absence of uid pressure in chamber 129, diaphragm 131 moves in phase with element 124 to cancel the displacement induced by reciprocation of element 124, thereby killing Jthe pumping action in pump 121. Sufficient iiuid pressure in chamber 129 partially restrains member 131 so that reciprocation of element 124 imposes pressure impulses on the uid trapped in chamber 123. The pressure impulses reciprocate member 131 to pump water through chamber 129.

VChamber 1148 communicates with iraput and output conduits 137 and 139, respectively, and is equipped with input and output check valve 132 and 134, respectively. Reciprocation of diaphragm 146 by pressure impulses communicated from chamber 123 will therefore be elfective to pump fuel through the chamber 148.

One advantage of the pumping system embodiment shown in FIGURE 3' over that shown in FIGURE 2 is that substantially higher pressures are employed in pumping water to the heating coil than are employed in pumping the fuel to the burner. In the embodiment shown in FIGURE 2, the pressures in chambers 123 and 129 are roughly equivalent due to their being in communication through member 131. However, in the embodiment of FIGURE 3, the fuel is pumped separately through the pump 143 so that its pressure may be separately regulated either by appropriate design of the relative sizes of chambers 123, 147 and 148 or by the provision of an appropriate snubber device in uid communication with chamber 148.

FIGURE 4 shows another embodiment of the pumping system of the present invention. In this embodiment, the first pump 149 includes walls 151 defining a chamber 152, and a reciprocating element 153 which may take the form of a flexible diaphragm formed of materials similar to those used in fiexible diaphragm 17. A second pump 156 is provided, having input conduit 157 and output conduit 158. Pump 156 need not be a reciprocating pump, but may be of any type appropriate to this application. Input conduit 157 receives water from a reservoir such -as that illustrated as 75 in FIGURE l, and the output conduit 158 supplies water under pressure to a heating coil such as 74 of FIGURE l.

A branch of output conduit 158 communicates fluid pressure to a coupling means interposed between the drive means 126 and the diaphragm 153. In this embodiment, the rod member 130 of the embodiments of FIGURES 2 and 3 is formed in two parts, 13G-a and 130-b, with part 130-a bearing on the drive means 126 and part 13G-b bearing on the diaphragm 153. The coupling means 154 is interposed between parts 13G-a and 13G-b and operates to transmit the reciprocation of part 13o-a to part 130-b only when supplied with fiuid pressure from output conduit 158. Coupling means 154 could be a hydraulic valve lifter such as those located on the push rods of automobile engines.

It may be seen then that when the fluid pressure output of the pump 156 is insufficient, the coupling means 154 will not be supplied with fluid pressure to pump it up, and it will not transmit the reciprocations of part 130-a to part 13G-b. When sufficient pressure is available from the output of pump 156 to coupling means 154, the coupling means is pumped up, and the operation of the drive means 126 will reciprocate diaphragm 153 to pump fuel through chamber 152 to a burner 66. Pump 149 is equipped with input and output conduits 137 and 139 and inlet and outlet check valves 132 and 134, respectively, which operate similarly to those elements of like numbers in pumps 143 and 121.

FIGURE depicts yet another embodiment of the pumping system of the present invention including a first pump 159 similar to pump 149 depicted in FIGURE 4. A drive means 161 reciprocates a rod member 130 attached to the diaphragm 153. As shown in this embodiment, the drive means 161 includes a rotating shaft 162 having an offset crank portion 163 and an arm 164 journaled on the crank portion 163 for freedom of rotary movement thereabout. The arm 164 is attached to the rod member 130 by a connection such as a pin 166 which permits pivotal motion of the arm 164 about the rod 130. It will be seen that this part of the drive means 161 is similar to the drive means 126 and 18 of the previous embodiments.

A second pump is provided which may be the same as the pump 156 described in conjunction with FIGURE 4. A branch of the output conduit 158 leads to a coupling means 167 having a rotating input shaft 168 and having for its output shaft rotating shaft 162. The coupling means 167 may be a conventional hydraulic clutch responsive upon the supply of sufficient pressure of fluid from the output conduit 158 to transmit rotation of the input shaft 168 which is coupled to a motor (not shown) to the output shaft 162. When insufficient water pressure is available in the output conduit 158 to cause the engagement of the coupling means 167, the coupling means will not transmit rotating power to operate the eccentric drive means 161. Diaphragm 153 of pump 159 will then not be reciprocated to pump fuel.

While the foregoing embodiments of the pumping system have been described and their operation outlined in terms of association with a high pressure hot water washing apparatus, such as that schematically shown in FIG- URE l, it must be appreciated that their application is equally useful to other water heating apparatus such as industrial low pressure hot water heaters, steam generators, and steam cleaning apparatus, wherein water is supplied by one pump under pressure to a coil for heating and the coil is heated lby a burner fired by a burner fuel. The pumping system, indeed, is useful in any application in which it is desired to positively interlock the pumping of two different fiuids so that one of the fluids will not be pumped when the other fluid is not being pumped.

From the foregoing it may be seen that a pumping system has been provided for pumping two different liquids in which the pumping of the second liquid is dependent upon pressure created `by the first liquid being pumped, and that when this pumping system is applied to a Water heating system to pump the fuel and water to the system, overheating and damage to the water heater is positively prevented in the event of a failure of the water supply by interfering with the pumping action of the fuel pump. The pumping system also immediately, reliably and cleanly terminates fuel supply to the heater upon any termination of water supply to the coil of the heater, and -withholds fuel supply to the heater until fuel and water supply pressures are suicient for proper operation.

We claim:

1. In a system for pumping two different liquids,

a positive displacement first pump for one of said liquids,

said first pump having walls defining a pumping chamber,

a reciprocating element formed for alternately increasing and decreasing the volume of said chamber,

a killer member cooperating with said walls and said reciprocating element in defining the pumping chamber, said killer member being movable in response to pressure changes in said chamber for rendering movement of said reciprocating element ineffective to pump liquid from said chamber, by compensating for the decreased volume of said chamber,

a second pump for the other of said liquids, and

means connecting said killer member with said second pump for restraining said killer member against said movement when said other liquid is being pumped by said second pump,

said reciprocating element comprising a first fiexible diaphragm, and said killer member comprising a second exible diaphragm,

said means comprising a second chamber defined by said walls and separated from said pumping chamber by said second diaphragm, said second chamber being connected to said second pump to apply pressure derived from said second pump to said second diaphragm to accomplish said restraint, said second chamber forming the pumping chamber of said second pump and said second fiexible diaphragm serving as the reciprocating element to alternatively increase and decrease the volume of said second chamber to pump liquid therethrough.

2. A pumping system as described in claim 1 and wherein said first and second chambers have respective inlet and outlet conduits, each of said conduits being equipped with a one-way check valve, whereby backfiow of pumped fluid will `be prevented.

3. In a system for pumping two different liquids,

a positive displacement first pump for one of said liquids,

said first pump having walls defining a pumping chamber,

a reciprocating element formed for alternately increasing and decreasing the volume of said chamber,

a killer member cooperating with said walls 'and said reciprocating element in defining the pumping chamber, said killer member being movable in response to pressure changes in said chamber for rendering movement of said reciprocating element ineffective to pump liquid from said chamber by compensating for the decreased volume of said chamber, a second pump for the other of said liquids, and

means connecting said killer member with said second l pump for restraining said killer member against said movement when said other liquid is being pumped by said second pump,

said reciprocating element comprising a first flexible diaphragm, and

said killer member comprising a second fiexible diaphragm,

said means comprising a second chamber defined by said walls and separated from said pumping chamber by said second diaphragm, said second chamber being connected to said second pump to apply pressure derived from said second pump to said second diaphragm to accomplish said restraint, said second chamber forming the pumping chamber of said second pump and said second flexible diaphragm serving as the reciprocating element to alternatively increase and decrease the volume of said second chamber to pump liquid therethrough, said system further comprising Walls defining third and fourth chambers, said third and fourth chambers being separated by a third flexible diaphragm, said third chamber being in sealed fluid communication with said first pumping chamber, whereby said third diaphragm will be reciprocated to pump fiuid through said fourth chamber by impulses induced in said first chamber by rcciprocation of said first flexible diaphragm at such times as the rcciprocation of said second flexible diaphragm is resiliently resisted by the pressure of fluid within said second chamber.

4. A pumping system as described in claim 3 and wherein said second chamber and said fourth chamber each have an inlet conduit and an outlet conduit, each of said inlet and outlet conduits having one-Way check valves interposed therein, whereby backow of pumped fluid will be prevented.

5. In a system for pumping two different liquids,

`a positive displacement first pump for one of said liquids,

said first pump having walls defining a pumping chamber,

a reciprocating element formed for alternately increasing and decreasing the volume of said chamber,

a killer member cooperating with said walls and said reciprocating element in defining the pumping chamber,

said killer member being movable in response to pressure changes in said chamber for rendering movement of said reciprocating element ineffective to pump liquid from said chamber by compensating for the decreased volume of said chamber,

a Second pump for the other of said liquids, and

means connecting said killer member with said second pump for restraining said killer member against said movement when said other liquid is being pumped by said second pump,

said reciprocating element comprising a first flexible diaphragm and said killer member comprising a second flexible diaphragm,

said means comprising `a second chamber defined by said walls and separated from said pumping chamlber by said second diaphragm, said second chamber being connected to said second pump to apply 12 pressure derived from said second pump to said second diaphragm to laccomplish said restraint, said means further comprising a movable pressure responsive element disposed in said second chamber and communicating with said second pump means to transmit pressure derived from the output of said second pump means to said second diaphragm to restrain the same against movement, a spring means being interposed between said movable pressure responsive element and said second diaphragm to limit pressure applied to said second diaphragm.

6. In a system for pumping two different liquids, a positive displacement first pump for one of said liquids,

said first pump having wall defining a pumping chamber,

a reciprocating element formed for alternately increasing and decreasing the volume of said chamber,

a killer member cooperating with said Walls and said reciprocating element in defining the pumping chamber,

said killer member being movable in response to pressure changes in said chamber for rendering movement or' said reciprocating element ineffective to pump liquid from said chamber by compensating for the decreased volume of said chamber, a second pump for the other of said liquids, and means connecting said killer member with said second pump for restraining said killer member against said movement when said other liquid is being pumped by said second pump, said reciprocating element comprising a first flexible diaphragm and said killer member comprising a second fiexible diaphragm, said means comprising a second chamber defined by said walls and separated from said pumping chamber by said second diaphragm, said second chamber being connected to said second pump to apply pressure derived from said second pump to said second diaphragm to accomplish said restraint, said means further comprising a movable pressure responsive element disposed in said second chamber and communicating with said second pump means to transmit pressure derived from the output of said second pump means to said second diaphragm to restrain the same against movement, said second pump -being a diaphragm pump and said system further comprising an eccentric drive means for reciprocating said first flexible diaphragm and the diaphragm of said second pump, said first and second pumps each having inlet and outlet conduits and one-way check valves in said inlet and outlet conduits to prevent backfiow, said second pump having a pressure dome coupled to its output downstream of said outlet check valve to smooth out the pulsations therein, said first pump further comprising a first rod member operatively coupled to said eccentric drive means for rcciprocation thereby, a first plate member confronting said first diaphragm and the end of said first rod member remote from said drive means, a first spring means biasing said first diaphragm toward said drive means to increase the volume of said pumping chamber, a second plate member bearing on the side of said second diaphragm opposite said pumping chamber, said movable pressure responsive element comprising an element in sealing relationship to the walls of a portion of said second chamber and exposed on one side to the pressure generated by said second pump, a second rod member having one end in contact with the other side of said element, and a second spring means interposed between the end of said second rod member remote from said element and said second plate member, whereby movement of said element in response to the pressure generated by said second pump means will regulate the force applied by said second spring means to said second diaphragm to restrain said second diaphragm against reciprocation, and stop means interposed in said second chamber for limiting movement of said second rod member toward said second diaphragm to limit the force applied thereto.

7. High pressure washing apparatus comprising a water delivery line,

a delivery valve on the free end of said delivery line,

a heating coil for said water,

a water pump for pumping water through said heating coil and out said delivery line at a relatively high pressure when said delivery valve is open,

unloading means for relieving the high back-pressure created against said water pump upon closure of said delivery valve, said unloading means comprising a discharge line connected to said unloading means,

a pressure regulator in said discharge line normally closing said discharge line, said pressure regulator, upon the closure of said delivery valve, opening said discharge line to permit the water pump to discharge water therethrough,

a pressure sensitive valve member interposed in said delivery line downstream of the connection of said discharge line to said delivery line, opening in response to a rise in the output pressure of the water pump, and closing in response to a drop in said pressure,

a connector line joining said delivery line downstream of said valve member to said pressure regulator,

a fuel burner for heating said heating coil, and

a fuel pump for supplying fuel under pressure to said burner,

said fuel pump comprising Walls defining a pumping chamber,

a reciprocating element formed for alternately increasing and decreasing the volume of said chamber,

a killer member cooperating with said walls and said reciprocating element in defining said pumping chamber, said killer member being movable in response to pressure changes in said chamber for rendering movement of said reciprocating element ineffective to pump fuel from said chamber, and

means connecting said killer member with said Water pump for restraining said killer member against said movement when suicient water pressure is present at the output of the water pump,

said reciprocating element comprising a first flexible diaphragm and said killer member comprises a second flexible diaphragm,

said means comprising a second chamber defined by said Walls and separated from said pumping chamber by said second diaphragm, said second chamber being connected to said Water pump to apply pressure derived from said water pump to said second diaphragm to accomplish said restraint, and a movable pressure responsive element disposed in said second chamber and movable therein in response to pressure derived from said water pump, said fuel and water pumps being diaphragm pumps and each having inlet and outlet conduits and one-way check valves in each of said conduits to prevent backflow of fuel and water, said system further comprising eccentric drive means for reciprocating said first flexible diaphragm and the diaphragm of said water pump, said water pump having a cushion dome coupled to its output conduit to smooth out the pulsations in the water therein, said fuel pump further comprising a iirst rod member operatively coupled to said drive means and said first exible diaphragm for transmitting reciprocatory movement therebetween, said movable pressure responsive element cornprising an element disposed in movable sealing relation to the walls of a portion of said second chamber and exposed on one side to the pressure generated by said Water pump, a second rod member having one end in contact with the other side of said element, and spring means interposed between the end of said second rod member remote from said element and the side of said second flexible diaphragm facing away from said pumping chamber, whereby movement of said element in response to the pressure of the water output of said Water pump will regulate the force applied by said spring means to said second diaphragm to restrain said second diaphragm against reciprocation.

References Cited UNITED STATES PATENTS 731,241 6/ 1903 Steiner 103`44 1,840,527 1/1932 Rabezzana 103-44 2,619,907 12/ 1952 Paterson 103-37 2,915,016 12/1959 Weaver et al 103-44 3,261,330 7/1966 Arant 103-9 XR 3,359,909 12/1967 Johnson et al. 103-6 1,116,494 11/1914 Setz 123-140 FOREIGN PATENTS 597,106 1/ 1948 Great Britain.

WILLIAM L. FREEH, Primary Examiner U.S. Cl. X.R. 103-38, 44, 150

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