US 3306209 A
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Feb. 28, 1967 H. P. TYLER EUMP Filed March 26, 1964 United States Patent Gitice 3,385,289 Patented Fei). 28, 1957 3,305,299 FUMP Henry P. Tyler, South Bend, Ind., assigner to The Bendix Corporation, South Bend, Ind., a corporation of Delaware Y Filed Mar. 26, 1964. Ser. No. 354,887 2 Claims. (Cl. 1tl3-6) This invention relates to a pump capable of using mechanical power to pressurize and proportion multiple liquids supplied to it.
lt is a principal object of my invention to provide a pump having multiple stages or sections each of which is capable of independently pumping a uid and/ or propoztioning a combustion of fluids while pumping them.
lt is a further object of my invention to provide a pump as aforementioned with a pressure responsive control means common to all stages.
It is also an object of my invention to provide a pump with a means to circulate the incoming iluid throughout the pump to provide cooling before pressurizing.
Still another object of my invention is to provide an electrohydraulic servo valve for controlling the above mentioned pressure responsive control means.
A still further object of my invention is to provide a multiple stage pump which is so constructed to allow access to any stage thereof without complete disassembly.
An additional object of my invention is to provide a pump having means to proportionally mix two fluids and thereafter deliver same.
A further advantage of my invention is in the means for allowing the passage of liquids through each of the pump stages in the directions normally induced, even though that stage is non-operating.
Other objects and advantages will be apparent from the following detailed description of the invention as related to the drawing showing a cross-sectional form of a three stage pump and control means constructed in accordance with the principles of my invention.
As seen in the drawing I have provided a pump 1t) f having three distinct rotors 12, 14 and 16, on a common axis each of which is aixed to respective. shaft portions 18, 2li and 22 that are interconnected by appropriately designed spline lits so as to provide a common drive means connected to a stub shaft 24 that may be driven by a power plant (not shown). Each of the rotors contain reciprocating plungers; i.e., rotor 12 has reciprocating plungers 26, rotor 14 has reciprocating plungers 28 and 30, and rotor 16 has reciprocating plungers 32.
As will appear obvious to those skilled in the art, the purpose of these plungers is to draw in uid from each of the fluid inlets 34, 36, 38 and 40 and expel fluid at discharge ports 42, 44 and 46. It should be noted that the discharge at port 44 will contain a combination of fluids ingested at inlets 36 and 40, as will be hereinafter further explained.
The plungers are reciprocated by a non-rotating, tiltable cam plate (S) 48, S and 52 each of which are mounted by trunnion bearings in the housing (not shown) as are familiar to those skilled in the art to which my invention relates. Smooth, sinusoidal motion is imparted to the plungers by means of shoes 54 or 56 and 58 having respective swivel sockets 60, 62 and 64 connecting the respective plungers thereto. Additionally, the plungers 36 are similarly mounted to shoes 66 by swivel sockets 68.
Plunger retraction does not depend upon individual cycling springs, which could be provided if desired, but rather is semi-positive. Auxiliary cam plates 70, 72 and 74 provide the retraction by holding the plunger slippers or shoes 54, 56, 58 and 66 against the non-rotating, tiltable cam plates or swash plates, as they may be termed, as by springs 76, 78 and 80 operatively connected to the auxiliary cam plates. lt should be noted that, as shown, centrifugal force supplements retraction and axial play is limited by a shimmed physical stop or bearing plates 82V, 84 and 86. The result is reliable operation with high volumetric eiiiciency. Y
Each of the aforementioned rotors and reciprocating plungers is controlled by removable ported valve plates 88, 98 and 92, which by their removable nature allow for valving refinements and changes by relatively flexible, quick, and inexpensive changes as compared to other pump concepts familiar to those skilled in the art to which my invention relates. Pressure balanced ferrules 94, 96 and 98, for example, serve to seal the valve plates to the housing so that extreme running parallelism of rotor faces to housing faces is not required.
As seen in the drawing from the drive shaft 24 forward, the respective sections are adaptable for pressurizing and providing multiple uids. There are no direct leakage paths between the sections containing rotors 12 and 14 in order to allow the pumping of two or more fluids which may react violently if exposed to each other. Furthermore, the main housings 180, 102, 104 and 166V part along the faces 108, 118 and 112 of each of the sections for individual access to the rotors 12, 14 and 16.
lt should be noted that the fluid introduced to plungers 30 by means of internal passage 114 is exhausted to another internal passage 116 that is communicated with the internal inlet passage 118 for the plungers 28. Thus allowing the comingling of fluids to be exhausted by plungers 28 lto the internal passage 120 terminating in the discharge port 44.
In order to provide for means of collection of fluid leakage, l have shown the rotors 12 and 14 to have axial passages 122 and 124 which communicate with radial passages 126 and 128 respectively in the valve plates 88 and 90 leading to an inlet for the plungers 26 and 28 respectively. The inlet for the plungers 26 being provided by an internal passage 130 and the discharge passage for the same plungers being provided by another internal passage 132. As for the rotor 16, I have provided a unique way rotating mechanism by allowing the uid from the inlet port 38 passing by way of passage 134 to be introduced to axial passages 136 through the rotor to flow into a pump cavity 138 for the rotor 16 and circulate around the aforementioned members before being directed to another passage 140 formed by clearance between the housing 106y and the rotor 16 that is arranged to communicate with a radial groove 142 in the valve plate 92 that opens into a bore 144 in which the plungers 32 reciprocate. This feature is very important if reactive fluids are being pumped by the rotor 16 in that it will minimize the reactive nature thereof while, by passage of the large ow rates (instead of only leakage rates) through the case, lowering the bulk temperature and reactivity rate. Furthermore, the centrifugal forces of the rotor 16 will force a correct coolant ow throughout the cavity 138.
The cam plates 48, 50 and 52 are positioned by means of a pair of pistons 146 and 148 that directly position the swash plate 48 which is linked by push rods 150, 152 and 154 to the remaining cam or swash plates 50 and 52 as well as a spring return means 156. As seen, the push rods contain simple O-ring type seals to allow fluid integrity of each ofthe pump cavities 158, and 138. The small pressure differentials in the aforementioned cavities allow use of these relatively simple seals. In addition, similar seals will be appropriately provided in the housing sections to prevent fluid leakage from one cavity to the other about the shafts. l
Variable delivery control for each of the pump sections is provided by the action of the two opposed actuator pistons 146 and 148 which with the assistance of the push of cooling the rotating and nonrods 150, 152 and 154 plus the return spring 156 govern the `angle of the cam pla-tes 48, and 52 to cause the cam plates to move in unity. As seen the piston 148 is biased by a spring 254 to maintain the abutting relationship of the pistons 146 and 148 with the swash plate 48. The pistons 146 and 148 are positioned normally by duid pressure delivered thereto by internal passages 161 and 162 that extend through housing sections 100 and 102 to emerge at respective orifice inlets 164 and 166 adjacent a machined face of a radial ange for section 102 to which I have joined a dry coil mechanical feedback servo valve 168, as by vbolts (not shown), which valve is of a type -to have low hysteresis, with means to convert a command signal to the required displacement of pumping elements, of a somewhat similar type as the Patent No. 2,964,018 issued December 13, 1960, to the common assignee. More particularly, the permanent magnet type torque motor as will be embodied to bring about valve control and as is shown in the aforementioned Patent No. 2,964,018, is isolated from the hydraulic portions of the valve by a torque tu'be 170 which acts as both a fluid seal and torque motor centering spring. Motor-developed torque is transmitted through this tube to a flapper 172 which is positioned to have portions thereof overlying but spaced from two parallel nozzles 174 and 176 to increase, decrease or equalize the flow therefrom. As seen, the nozzles 174 and 176 lare respectively connected to passages 178 and 180 by the radial passages 182 and 184, and the passages 178 and 180 terminate in respective valve chambers 186 and 188 at each end of a spool valve 190.
Fluid pressures developed by a familiar :means such as a reservoir 192, a pump 194 and accumulator 196 having appropriate conduits 198 and 200 connected respectively to an inlet 202 and an outlet 204 that is in turn communicated with passages 206 and 208, respectively, extending through sections 104 and 102 to enter the valve 168 by means of respective passages 210 and 212. The valve passage 210 terminates in an inlet chamber 214 having a filter means therein which is arranged to filter the pressurized fluid before its passage through the end located orifices 216 and 218 that communicate with the respective passages 178 and 180. In addition, the inlet chamber 214 is `communicated by passages 220 and 222 to respective grooves 224 and 226 in the valve housing 168 that are normally closed off from communicating with an internal bore 228 by the valve end lands 230 and 232. The spool valve 190 also contains center valve lands 234 and 236 which apportion the bore 228 into three chambers 238, 240 and 242 which are respectively connected with passages 244, 212 and 246. As is also seen the apper 172 is provided with a projection 248 which is adapted to ride between the lands 234 and 236 and thereby provide mechanical follow-up of valve movement. Therefore, motion of the flapper 172 creates, a differential pressure in chambers 186 and 188, which pressure acts on the ends of the spool valve `to displace it, so that either passage 220 or 222 is communicated by way of chambers 238 or 242 to passage 212 leading by way of passage 208 to conduit 200 terminating at the reservoir 192. Due to the mechanical connection of the fiapper to the v-alve spool 190, movement of the spool generates a countertorque through the feedback tension spring to return the apper to the null position when the spool has reached the commanded position. Because of the inherent fast response of such a valve, action is modified by interposing the orifices 164 and 166 in the passages connecting the servo valve stage chambers 238 and 242 to the pump actuator pistons 148 and 146, respectively, and thereby slow pump response to the specified valve. i
In order to allow the passage of liquids through each of the stages of my pump in the directions normally induced, while non-operating, I have provided three ball check valves 253, 250 and 252 which parallel the normal pumping paths as shown.
It should be noted that push rod links govern relative displacement of the pumping sections. And that by length revision the delivery rates maybe changed for each stage.
In operation, the pressurized hydraulic fluid delivered by conduit 198 to inlet 202 and by appropriate passages to the inlet cavity 214 of the electro-hydraulic valve 168 will normally ybe equally exhausted through the nozzles 174 and 176 to hold the valve spool 190 in the null condition and returned to the cavity or groove 240 which is communicated by appropriate passages to the discharge 204 and the conduit 200 to the reservoir 192. In the event a control signal is provided to the torque motor controlling the dapper 172 one or the other of the nozzles will be restricted to position one or the other of pistons 146 and 148 and thereby adjust the angle of the cam plates 48, 50 and 52 and vary the fluid discharge at ports 42, 44 and 45. It should also be understood that by varying the cam plate 50 and due to the concentric arrangement of plungers 2S and 30 the ratio of fluid discharged from plunger 30 to the inlet for plunger 28 will remain constant.
Although this -invention has 'been described and shown with reference to a particular embodiment of the invention, the principles involved are susceptible of numerous other applications and embodiments which will be apparent to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.
1. A multi-uid pump comprising:
a first, second and third pump having respective first,
second and third rotors, pistons and cam plates;
a means to collectively control each cam plate includlng! a pressure responsive member arranged to operate one of said cam plates,
a link means to connect said one of said cam plates to each of the other of said cam plates, and
a spring means operatively connected to said cam plates and link means to oppose said pressure responsive member;
a control valve arranged to actuate said pressure responsive member;
a first passage means in said pump for delivering separate fluids to each of said pumps with one of said passages adapted to supply a fluid to cool the pump before being circulated by centrifugal force to the pump pistons, and
a second passage means in said pump for exhausting fluids from each of said pump means with one of said passages adapted to intermix a pair of uids in a constant ratio throughout a control range for said pump; and
a bypass means for each of said fluids operatively connected between said first and second passage means to permit normal circulation of fluid regardless of pump operation.
2. A pump comprising:
a means to pump a plurality of uids including a means to ingest and pressurize each fluid;
a control means to modulate the amount of ingestion and pressurization of each fluid;
a pressure responsive means arranged -to actuate said control means having an interconnecting means for each of said control means;
a reference means operative-ly connected to said interconnecting means and arranged to oppose said pres` sure responsive means;
a means to circulate each of said fluids through said pump regardless of operation of said means to pump the plurality of fluids;
a servo valve for said pressure responsive means, said servo valve having a housing;
a spool valve mounted reciprocally in said housing;
end chambers being defined between the spool ends and said housing, said spool having a mid-position References Cited by the Examiner UNITED STATES PATENTS 1,322,236 10/1919 Fish 103-9 2,445,281 7/1948 Rystrom 103-162 DONLEY J.
6 McGowan 103-6 Chiantelassa 103-11 Blenke 103-162 Budzich 10? 162 Manning et al. 103-162 Pesce 103-162 Boydell 103-4 Laing 103-5 Tyler 103-162 Korlak 103-9 STOCKING, Primary Examiner. MARK NEWMAN, Examiner.
W. L. FREEH, Assistant Examiner.