3 1 2 7 5 1 2 2 2 Uni'ted States Patent Office p.tented Sept. 27, 1966 3,275,22 2 ROTAR Y LIQUID PISTON MACIHNES Andre J. Meyer, 848 N. Jackson Drive, Fayettev ille, Ark. 72701 Filed Jan. 11, 1965, Ser. No. 424,581 5 15 Claims. (Cl. 230-116) This invention relates to rotary liquid piston engines and to the combination of such an engine with a rotary liquid piston pump. 10 The basic idea of rotary liquid piston gas pumps was originat ed by Nash (Patent No@ 953,222), who created a "displac ement structure" by providing a cylindrical case or housing, in which a rotor or impeller with radial vanes is eccentrically mounted. When the rotor revolves and 15 the case is filled with sufficient water to keep all vane tips submerg ed, a liquid ring is formed, the inside diameter of which approaches the rotor hub much closer on one side than on the other. Therefore the empty space between a pair of adjacent vanes varies from a minimum to a 20 maximu m to that minimum again during each revolution. Provisio n of suitable inlet and outlet ports as well as proper sealing structures is needed to use this variable space for pumping. To better understand the rotary liquid piston principle, 25 it must be realized,that the liquid is subjected to a centrifugal force field, which is very much stronger than gravitation. While the acceleration of gravity (g) in the lower atmosphere is nearly constant over the whole surface of the earth, the centripetal acceleration of the liquid 30 in the rotary liquid piston pump is inversely proportional to the local radius of rotation and directly proportional to the square of the liquid velocity, which roughly equals the peripheral speed of the impeller. In order to prevent the reversal of liquid flow - direction 35 under the infltience of local high gas pressure, the rotor diameter and speed must be selected so, that the stagnation pressure of the liqtiid exceeds the maximum desired gas pressure. Consequently in practical pumps the accelera tions of the liquid vary from 160 g. in a vacuum 40 pump to 2000 g. or more in high pressure pumps. As a result, dependent on the application, the weight of water in the liqtiid ring varies between 5 and 62.5 tons per cubic foot. This weight is supported by the housing wall and since all weight vectors are directed radially outward 45 and gravitational effects are ne.-ligible, the inside water level of the ring must be concentric with the casing wall, regardle ss of the position of the vanes relative to the liquid. Evidently no small disturbance can deform the level @of water of such high specific gravity. 50 As the impeller revolves, the inner liquid ring surface moves in and out of the chambers or buckets formed by eaeb adjacent pair of rotor vanes. Therefore this surface acts like the top of a piston in a cylinder, except insofar that the liquid piston area varies to fit the shape of the 55 bucket. The machine is indeed a displacement structure with a liquid piston capable of raising the static pressure of a gas withotit appreciably affectin@ its kinetic energy. It is not a flow machine like a centriftigal pump or turbine in which static pressure @changes are the result of trans- 60 formatio ns from kinetic into potential energy and vice versa. As the art of liqtiid piston pumps developed, the simple cylindric al case was ibandoned in favor of double, triple or even multiple lobe housings, which made the pump 65 double, triple or multiple acting. In principle, however, they remained liquid piston displacement strur-tures, even - though the ambigtious name of hydro turbine obscures that fact. 70 Althou.- h other displacement structures have been used for either piimps or motors, no attempt was made to 2 adapt rotary liquid piston machines of the type described for the purpose of engines, although the following comparisons indicate that they may have certain advantages for this application. Conventional piston engines require chemically rich mixtures of hi.-h grade fuel and air, which in the motor are contaminated with residual exhaust gases. As a result the combustion products are only partially oxidized, obnoxious, poisonous and cause smog. The gases are released at high pressure, which means energy loss and noise. These engines further -operate on a high frequency batch process, requiring a large number of Gylinders in order to obtain a reasonably smooth torque. This leads to complexity and bulk, so that a modern V-8 usually occupies a space of more than 100 times the engine displacement per revolution. In a rotary liquid piston engine the compression, combustion and expansion tale place in separate specialized un s. ke in gas turbines the air-fuel ratio will be I to 4 times the stoichiometric ratio. This means completecomibustion even of low grade fuels, clean exhaust, and ftirther, because the combustion products are expanded to atmospheric pressure, there will be lower exhaust temperatures, higher efficiency and less noise. The zero clearance volume will also improve the pump efficien--y. Besides that, ff there are n vanes on the impeller, there are 2n pistons completing a cycle each revolution. Thus the torque will be smooth without complication, in fact the whole rotor assembly can be made as a single permanent mold casting, the only moving part in the machine. Furthermore all dynamig and gas forces are inherently balanced, so that the rotor bearings carry only the rotor weight. Finally the machine will occupy a space of less than 40 times its expander displarement per revolution, and a single combustion chamber, without ignition device other than a glowplug for stai-ting, will take care of the combustion of the gases delivered by the gas and air PUMPSObviously a large and varied number of applications of this invention can be made. By way of example a motorcompressor, more specifically a refrigerant compressor driven by a natural gas-air engine will be discussed. Obviously a compressor for any other gas, including one for natliral gas pumping stations, is very similar in principle, only an air compressor requires two instead of foii-r pumps. All these machines have no power output shaft, therefore an industrial natural gas-air engine driving a shaft with sheave for multi-ple V-belt drive will also ibe disclosed. It must be understood that a mixture of air with any fuel may be used to drive the motor, which furnishes the energy needed to raise the pressure of any gas, vapor or liquid, or a mixttire thereof, or to deliver shaft power to any mechanical contrivance. One object of the invention is the provision of a rotary liquid piston engine capable of producing power smoothly, efficiently and silently witho.ut the emission of objectionable exhaust gases. Another object is the provision of a rotary liquid piston machine combining a gas motor and a gas compressor in such a manner that the drive torque developed by the motor is transmitted internally straight-away to,the compressor. Thus the torque reactions on the motor and piimp housings are balanced against each other, so that no reaction effect is transmitted to the stirroundings. Another objec@t is to provide a rotary motor-compressor unit having a rotor supported on bearings not subjected to gas or dynamic loads and having no other moving parts, so that long trouble free life may be expected. Still another object is to provide a rotory motor-gas pump in which the amount of axial gas leakage is minimized by the elimination or reduction of the axial pressure difference between adjacent elements of the machine.

3 Other objects and advantages will hereinafter appear. In the drawings: FIGURE I is a plan view of the motor-compressor. FIGURE 2 is a side elevation. FIGURE 3 is an end view of the mot-or side. FIGURE 4 is an end view of the -pump side. FIGURE 5 is a bottom view. FIGURE 6 is a partial longitudinal section limited to the length of the stator spindle. The latter is shown in side view, otherwise the section is substantially in the vertical plane, except as indicated by 6-6 of FIGS. 23 and 24. FIGURES 7 through 22 are normal cross sectionq through the stator spindle, at the stations in FIG. 6 that carry the same number as the section. All sections are drawn looking from left to xight. FIGURE 23 is a cross section through the motor driven by combustion products, taken along 23-23 in FIG. 6. FIGURE 24 is a cross section through the refrigerant compressor taken along 24-24 in FIG. 6. FIGURE 25 is an end view of the cooling liquid circulation unit mounted on the stator spindle at the motor side. FIGURES 26a, 26b and 26c are partial sections along the line 26-26 in FIG. 25. FIGURE 27 is an end view of the air entrance and malce-up Water supply unit mounted on the stator spindle at the pump side. FIGURES 28a and 28b are partial sections along the line 28-28 in FIG.!27. FIGURE 29a is a section along the line 29a-29a in FIG. 26b. FIGURE 29b is a @section alon.- the line 29b-29b in FIG. 26c. FIGURE 30 is a graph showing the pressure vs. rotation angle variation for all gases used in the refrigetant compressor. FIGURES 3 la and 3 lb are polar diagrams of gas pressures in an air motor and an air pump, before and after advancing the pump 60'. FIGURE 32 is a piping diagram or flow sheet for the refrigerator system. FIGURE 33 is a longitudinal section in the vertical plane of a gas-air engine with power output shaft. FIGURE 34 is the end elevation of the water in- and outlet units as seen from plane 34- 34 in FIG. 33. FIGURES 35 through 42 are normal sections of the stator spindle at the stations in FIG. 33 carrying the corresponding number. All sections are taken looking from left to right. The refrigerant compressor comprises a stationary housing 51 closed by the end covers 52, which support a shaft or spindle 53 (FIG. 6). In operation all these parts are stationary, the covers are fastened to -the stator housing by means of the screws 54 and rotation of the stator spindle is prevented by the timing screw 55 in the cover on the pump side. This screw is provided with a dog point 56.that fits in a slot 57 miued in the shaft. Axial movement of the spindle relative to the housing is prevented by the nut 58 enga.-ing the thread 59 on the shaft. Wheii this nut is tightened all parts contacting the outside diameter of the shaft between the nut and the shoulder 60 on the shaft are being compressed against the hub 61 of cover 52. The parts between the cover and the nut are provided with 0 rings 62, so that the spindle is not only rigidly held to the covers, but also the interior of the stator is sealed against leakage along the shaft to the outside. The end location described above is -used on both sides of the shaft, like parts being identified by the same numbers, but only one timing screw is shown, it is 90' out of place where shown. The end sections of the housing may be round , but in the motor and -pump areas the cross-section is an oval of 3,275,222 4 part of the housing containing the four pumps makes an angle of about 60' with the vertical axis of the part containing the three motors, the pumps being advanced in the direction of rotation, which is clockwise in FIGS. 23 and 24. The length of the minor axis equals the outside diameter of the rotor 63 plus a running clearance' The radii of curvature on this axis may have a length of half this diameter or larger, twice the amount being shown. These radii describe arcs subtending about 15' on either 10 side of the minor axis, which will be called the flanks of the oval. As shown they blend smoothly into the arcs forming what will be called the lobes. The machine will function, when the flanks intersectthe lobes, but may develop noise due to water hammer, unless they have com15 mon tangents ' I Partition walls 64, 65 and 66 run xadially inward from the outer wall of the stator housing@ They are bored out to the rotor outside diameter plus a small clearance, so that the rotor assembly, mounted on the spindle can be 20 slipped into the housing from either side after botb covers are removed. The rotor consists of a number of parts that are stacked up, dowelled and bolted together, so as to form a single rigid assembly, supported on the stator spindle by means 25 of one baR bearing 67 and one roller bearing 68. The latter has a removable inner race 69, so that no axi bearing loads can result from any difference in thermal expansion between rotor and shaft. In FIGURE 6, from the left or motor side to the right or pump side, the rotor 30 consists of the roller bearing retainer 70, which also houses the oil seal 71, the roller bearing housing 72 with the oil seal 73, the combined air and combustion product motor expansion wheels 74 and 75, the impeller for the air pump 76, refrigerant pump 77, another air pump 78, 35 the gas pump 79, the ball bearing housing go with the oil seal 81 and the bearing retainer 82 with oil seal 83. All motor wheels and pump impellers consist of a radial disc from one face of which a series of vanes are projecting in an axial direction. pattern o vanes is 1 entic 40 in all @cases and consists of a number of equally spaced radial vanes 84 as shown in FIGS. 23 and 24, some of which are provided with bosses 85 that are drflled for bolts 86 and bored for ring doivels 87. Short vanes 88 (FIG. 6) are provided on the outside diameter of the 45 bearing housings 72 and 30. The motor wheels have long vanes for the product gas expander on one side and short vanes for an air motor on the other. In operation, over the whole range of the expansion process, the gas pressure in the two small air 50 motors will be made identical to the pressure of the product gases, so that these cannot leak out axially. Since the air in the air motors is much cooler than the combustion -products, the provision of the two small air rnotors makes it possible to effectively seal against leakage of the cooler 5 5 air and thus contain the hot gases without trouble. On the roller bearing side the axial seal is accomplished by the oil seal 73, or a double acting seal 203 as shown in FIG4 33 may be used. On the pump side a heavier wall 60 65 with liquid injection and balanced air pressure, both to be discussed later, will prevent leakage from air motor to air pump and vice versa. In FIG. 23 the liquid level 89 intersects the stator spindle at the points 90 and 91 and between the level and the 65 spindle there is a gas filled crescent, divided in several spaces or chambers between adjacent rotor vanes. ' Evidently any chamber, the centerline of which is in the position 92, contains no gas, but as the trailing edge of the leading vane of this chamber passes point 90 on the 70 spindle, the liquid is compelled to rise away from the spindle surface, leaving a vacuum behind. If, however, an intake port 93 is formed in th6 spindle, gas under pressure may be supplied to destroy the vacuum and fill the space up to the water level. the same dimensions. The major axis of the oval in the 7,5 As the rotor revolves beyond the point of intake open-

5 ing, the gas volume in the chamber under observation enlarges, so that the weight of compressed gas it contains increases. This continues until the leading edge of the trailing vane of that chamber reaches the point 94 on the spindle, where the communication -between the intake port and the chamber under observation ceases. Fur-ther rotation results in more enlargement of the gas volume, so that the gas must expandto a lower pressure. When the chamber centerline arrives in position 95, which will be called top center, the volume occupied by the gas reaches a maximum value. If point 94 is properly selected, it can be arranged that the gas pressuxe in top center is atmospheric. In that case the trailing edge of the leading vane of all chambers arrivin.- at top center must line up with the opening edge 96 of the exhaust port 97. The exhaust period lasts until the leading edge of the trailing vane reaches point 91 on the spindle. It is to be noted that the process described is repeated on the lower half of the shaft, so that each of the twenty :Chambers shown are char.-ed and discharged twice per revolution. Evidently the displacement per revolution of the motor, measured with the exhaust products completely expanded, equals forty times the volume of gas contained in a chamber, when it is in the top center position. The process in the refrigerant pump of FIG. 24 starts with the intake opening at 98, where the liquid level intersects the spindle. The intake port 108 closes, when the chamber reaches top center, where the leadin.- edge of the trailing vane is at point 100, because here the inward stroke of the liquid commences. C6mpression lasts until the desired maximum pressure of the refrigerant vapor is reached, when the trailin,a edge of the leading vane is at point 101 at the oi)ening edge of the exhaust port 109. The exhaust takes place at constant pressure and is completed when the leading edge of the trailing vane arrives at the intersection 103 of the liquid level and ithe spindle, which point coincides with the closing edge of the exhaust port. From FIGS. 23 and 24 it will be clear, that twice per revolution all vanes are completely submerged in the liquid, while about half their length never comes in contact with any gas, hot or cool ' One reason for this situation is that the bolt bosses 85 must be kept out of the crescent to avoid difference in compression or expansion in the twenty chambers. In production, if the rotor is cast in one piece, these bosses can be eliminated and hence it will be possible to reduce its diameter by about 20%. This will necessitate an increase in the number of revolutions per minute, since the peripheral speed must be maintained. In that case the sp,ace to displacement ratio will reduce from 40 to 34, while the cooling @should still be adequate because of the continual wetting. The intake and exhatist ports 104 and 105 of the two air motors are like those of the combustion products motor, but they are of course much shorter axially, and althou,-h the exhaust ports are identical in cross-section, the intake ports are somewhat different, as shown in FIGS. 10 and 11. Also the intake ports of air, refrigerant, air and gas pumps, respectively 106, 108, 110 and 112 are similar, as are the exhaust ports 107, 109, Ill and 113 (see FIGS. 12, 13, 14 and 15). It will be noted tha-t the refrigerant pump has been pla I ced between two air pumps This was done because again, as will be shown later, it is t)ossible to eliminate axial pressure differences between air and refrigerant pumps and thus prevent refrigerant losses throiigh the water film between rotor partitions and the stator spindle. This cannot be done with a gas pump adjacent to the refri-erant pump, because the gas pressure must be 5 t. 10% higher than the air pressure to promote mixin.- in the combustion chamber. Furthermore some leakage of -as into the air is not detrimental, since both are to be delivered to the combustion chamber. 3,215,222 6 A series of longitudinal passages has been provided in the stator spindle in such a manner, that it is possible to connect all of the 28 ports with the proper passages. To facilitate understanding, the following table lists the letter symbols used to identify the various fluids flowing in the passages. Gas: Symbol Air -------------------------------------- A Combustion products --------- ------------- p 10 Natural gas-air mixture --------------------- Refrigerant ---- --------- R Water -------- ------------------ -------- i W Lubricant --------------------------------- L 15 Furthermore, if the letter symbol is primed, the fluid is a-t high pressure. Thus in the m(>tors A' and P' indicate gases flowing toward the motor, while G', A' and W are fluids flowing away from the pumps. FIGS. 7 throu.-h 22 show the cross drilled holes needed 20 to connect either the collector and distributor rings, or the intake and exhaust ports with the proper passages. Thus at station 7 the distributor ring 114, which is hollow inside, carries a boss 115, provided with an inlet 116 for the insertion of a pipe to connect it withthe combustion 25 chamber outlet shown diagrammatically in FIG. 32. At station 7 (FIG. 6) and in FIG. 7 the cross drilled hole 117 is shown, through which the hot high pressure gases enter the passages marked P'@ These are shown in FIG. 11 to be connected to the intake ports 93 by the holes 30 118. It is further shown that the exhaust ports 97 are connected to the passage marked P via the holes 119. In FlG. 8 the passages marked P lead the exhaust products by means of the holes 120 to the ring 121 with outlet 122. 35 The air motors draw compressed air from the hole 123 in the plu,@s 124. In FIG. 10 this hole is shown to communicate with the intake port 104 via the drilled pagsage 125. The motors discharge the expanded air via the exhaust port 105 and the hole 126 into the pas40 sage P, where it mixes with the expanded combustion products. This mixture leaves the outlet 122, which therefore is marked P+A. The air pumps take in air through the screen 127 surrounding the make-up water supply unit 128 (FIGS ' 45 1, 2 and 5). It enters a passage 129 (FIG. 28a) and reaches first the port 110 via the hole 130 at station 14, while the major part of the air continues to station 12, where it is @delivered to the port 106 via the hole 131. The compressed air discharged by the pumps flows from 50 the outlet ports 107 and 111, respectively via the holes 132 and 133 and the A' passage, which TUNS to the motor side to communicate with the hole 123: in the plugs 124 and in the opposite direction t@o communicate with the ring 134 to the outlet 135. 55 The refrigerant enters via 136, 19, R, 137 to port 108 at station 13 or section 24 and leave-s by route 109, 138, R', 20 to outlet 139. Natural gas and air, mixed in stoichiometric ratio, are admitted by the path 140, 21, G, 141 at 15 and 112. 60 They leave via 113, 142, G', 22, 143. In FIG. 6 the collector and distri.butor rings are shown in such a position that motor @outlets and pump inlets, which all are at atmospheric pressure, are turned up, while the high pressure in- or outlets are turned down. 65 These positions may be changed by turning the rings in any 6ther Tadial direction before tightening the nut 58 ' Besides the function of many little pistons, the liquid has other duties to perform, such as sealing, cooling and star-ting. 70 Further, to prevent the pump discharge gases to be trapped in the niachine, it is necessary to actually exhaust some liquid with those gases. Since this liquid is under pressure, it can be recovered cooled and returned to the machine, where it may serv@ to cool the hot side of the 75 spindle as well as to seal critical loca-tions. The dis.

3,275,222 7 charge of the motors being at atmo@pheric pressure, the retention of a few hot gas bubbles is not serious, since they will reduce in size by cooling and condensation, and later by compression, when the fresh charge enters. Any liquid that escapes with the motor exhaust will be lost, 5 therefore it is necessary to carefully limit the outflow, so that less make-up liquid is needed to maintain the level 89. In general the liquid Will be water, only when very hi-,h pressures are required, there is the choice between dou- 10 ble staging and the use of a liquid of bigher density. Also the gas to be pumped may sometimes be incompatible with water, so that other liquids must be used. The refrigerant condenser in this disclosure handles Freon 21, which for a home cooling unit can be used be- 15 tween 40 p.s.i. and atmospherir, pressure. This low pressure would normally be undersirable, because it requires a larger than usual piston displacement, but it is not objectionable for the rotary machine with its small space to displacement ratio. Further this refrigerant is total- 20 ly insoluble in water, therefore, also because of its advantage for cooling and easy availability, water is preferred. The sealing function -of the water will now be discussed in detail. 25 In operation the outside diameter of the rotor is always submerged. In the motor section the gas pressures in the three units are identical, therefore no axial flow of water is possible and consequently no partitions are needed in the stator housing at the separati6n of air 30 and product gas motors. The same argument applies to the pump section at the separation of Freon and air pumps, and since the gas pressure is only a few p.s.i. higher, also the partition between air and gas pump may be omitted in the housing. However, outside the 35 bearing housings 72 and 80 the stator housing is - circular and the gas pressure is atmospheric. Water in these spaces will whirl around at constant speed because of the vanes on the bearing housing. As a result the - pressure differences in the water at the partitions 64 and 66 are 40 n6t high. Neither are they very high at the partition 65, although in any plane through the centerline the radii of curvature at the pump and motor housings and hence the centrifugal forces are unequal. Here, - however, whatever leakage may take place in one direction will be 45 compensated for by the same amount of leakage in the opposite direction. Therefore it appears possible to allow a sufficient amount of clearance to prevent a metal to metal contact at the outside diameter of the rotor. Between the rotor and the stationary spindle it is 50 necessary -to prevent leakage of gas. This is of course ,harder to c@ontain and therefore a more detailed knowledge of the value of the gas pressure everywhere is cssen.tw. FIG. 30 shows that the rates Df pressure rise - differ 55 for the four gases used in this machine. The curves are for the applicable temperature ranges, considering the variation of specific heat therewith. The angles shown represent the rotation of the centerline of the leading vane of any chamber, and are measured in de- 60 ,grees from top cen-ter. Since expansion would take place between about the same temperatures, the curves may be used in reverse -to obtain results for expansion. Inspection of a large scale drawing of this kind shows practically coincide by starting the -compression of the product gas lo earlier than that of the air. For air and Fer<)n 21 the difference is 4'. For expansion of air and product gas the expansion of the latter would have 70 to start simultaneously. By these minor adjustments a perfect balance of axial pressures can be obtained, with the result, that axial le-akage between the motors and pumps can be avoided. To represent the condition at the partition 65, the 75 pressure variations on the adjacent air motor and air pump have been plotted in a polar diagram FIG. 31a, where @the distanr-e P,,, is proportional to the pressure of the air at an @angle of A,,, degree om top center. re and elsewhere in the diagram -the subletter in refers to the motor, while p refers to the pump. Furtlier: 10 is the poin@t where the intake port opens. IC is the p@oint where the intake por-t closes. EO is the ploint where the exhaust port opens. EC is the point where the exhaus@t port closes. In this diagram the pump and motor ihousin.- ovals are in line with each other. -FIG. 31b shows the sanie dia.-ram with the pump section rotated through an angle of 60' in the direction of rotation. In this case the hi.-h pressure land also the low pressure areas overlap most of the time. Instead of four long duration pressure suraes ont@he partition -there are now eight surges at about half @the pressure and during very small time intervals. Theoretically this reduces the leakage to about 15% of that in FIG. 31a, and since there is air leakage both ways, there is no net loss. Hence it may be concluded that,also here the axial leakage is insi.-nificant. Thus the axial gas leakage from motor to motor, from PumP tO Pump and from motor to plimp has been made negligil)le by means of small adjustments in timing and by advancing the whole pump section Eebout 601 with respect to the motor secti@on. Therefore internal leakage n-iust be confined to leakage in an axial direction through the bearing housings 72 and iSO and the oil seals 73 and 81. In a circumferential direction at any of the eight partition walls shown contaotin,@ Lthe spindle, there are four critical places, where the gas pressure around the shaft changes, from low to high or from hi.-h t-o low, in a very short distance. To prevent serious leakage at these locations, cooling water under pressure W' must be introduced at the four critical points marked in FIG. 31b located in such a manner, -that each high pressure area on the shaft is bracketed between two points, where water at a pressure equal to or higher than the maximum gas pressure is inj;ected in the filin b-@tween rotor and shaft. Evidently, if the rate of water eireiilation is high, the film thickness can be large and vice versa. The water circulation is illustrated in FIGS. 25 t@hrou.-h Z9bCo@oling water enters through the side openin.@ 144 of the liquid circulation unit 145. It passes through the annulus 146, streams along the inner wall of the spindle and via the holes 147 through the wall of the pipe 148 to the inside of that pipe, which is fastened to the unit, and leaves through the opening 149. The pipe is supported at the bore 150 and can be assembled with the unit 145, wbich is secured to the spindle by means of four studs 151, nuts 152 and lockwashers 153, A -asket 154, inserted between unit and shaft, seals all the open passages in the spindle on the motor side, except the annulus 146. At the location of the partition walls on the inside of the rotor, holes 15,5 have been drilled radially inward to meet the annulus 148 or the water space in the bore 1,50 at the end of the pipe. These holes 15,5 pass through the bores con-taining the plugs 124 but these have been provided wit-h circumferential grooves 156, so that some of @the coolin- water may pass around the plugs to be ejected into the clearance between rotor and shaft. FIG. 29b shows how holes 1,57 and 155 together cover the pose of extending the compressed air passage A' of FIG. 12 towards the air mo-tors. These plugs are held in position by the springs 153, whioh force them @against the 0 rin.@ 159. Otber 0 rings 160 prevent leakage of gas or water in the direction @of the springs. The plugs are further Iocated and prevented from turn-ing by means of the set screws 162, installed under the spacor ring 163. Like the tilning screw 55 the screw 162 has a doo point to fit in a milled slot, this time in the plug 124' that the -air and product gas curves can be made to (;5 critical -areas illustrated in FIG. 31b. The plu,@s 124 are inserted in the spindle for the pur-

9 The plug is further provided w-ith a tapped hole 16,4 to inser-t a screw to pull it out when desired. The make-up water enters the inlet 165 of the makeup water supply unit @or casting il28. From there some 'of the water may be supplied to station 16 via the holes i.167. It will be preferable, however, to make other arran,@ements, so as -to supply all critical sealing areas with coolin@ water, and to introduce all make-up water through the tube 16,8 and the @orifices 169 via the holes 13-1, into the intake ports 106 -Of the air pump at station 12. Tihen the coolin.- water can be increased by enlar.-in.- the rotor clearances, particularly at the pump side, which will reduce ithe make-up water requirement. The tube 168 is pressed int-o the unit 128 on one side and into a plug 170 on the other to seal it. This plu.is provided with an 0 ring 171 on its outside diameter, so as to prevent cooling water leaking into the air inlet 129. The unit 128 @consists of a water inlet platform and a base 172 linked together by four bolt bosses and two bosses for the drilled holes 167. Between all these bosses air,may enter @to reach the passage 129. A screen on the outside of @the casting, not shown in FIG. 28a, filters the air. Four studs 173, nuts 174 and lockplate 17,5 fasten .the unit to the pump side of the spindle. A gasket 176 between them seals all passages in the spindle on the pump side, except the air inlet, water inlet and stud holes. The machine will n-ot start until the liquid ring has been established. Assuming that it contains no water -at all, it is therefore essential that water enters as soon as possible. This suggests using water itelf for the purpose of starting by injecting it a@t high speed through one or more nozzles 177, shown in FIG. 23, while an inlet 178 is provided for such a n@ozzle in FIG. 24. The water jet will follow the contour of the oval, spread out and impact on the rotor vanes. Since the rotor is supp,orted on ball and roller bearings, it will spin easy until the liquid ring is partially established. The water impact can be supplem--nted by supplyin.-,compressed air to the air motors or even to the product gas motor. Air and even water i-inder pressure can be accumulated in one common or two separate taniks or be drawn from utility lines. Within two or three seconds the machine will start pumping, after which it will rapidly come to rated power and speed. When the machine is stopped, the water will gat@her in the lower half, which will make it difficult to start the next time. Therefore, a water drain system has been provided, consisting of a header 17,9, fed by the branches 180, 1,81, 182 and 183. These branches are &illed from the outside of theheader and sealed by the plug 184. To preven-t overfilling the machine with water, water level controls are provided on the inside of each end cover 52. They both consist of a ring @185 clamped between the cover and the spacer rin.- 163. This ring 185 is shown in cross section in FIG. 6 and in a plane perpendicular thereto in FIG. 29a. On the bottom it carries a skimmer 186 which passes any surplus water up into a hole 187 t-hat communicates with the outlet opening 188 in the cover. Rin- 1,85 is also provided with a hole 189 at the tOP, which toward the outside connects with the lubricant supply opening 190 in the end cover 52. Any oil introduced in this openin,@ flows through @the hole 191 into a groove on the inside o,f the spacer ring 163 toward the ball bearin.- 67 or the roller bearing 68. F@1G. 32 diagrammatically shows a piping dia.-ram for the refrigera-tor system in which: Vl is the valve for control of the starting water. V2 is the valve for control of drainin.- the machine@ V3 is the valve for control of natural gas supply. V4 is the valve for control,of make-up water. V5 is the valve for control of the cooling water jet pump. Vl, V2 and V5 are solenoid valves, that are eithet wide open or closed, V3 may be controllable within the 3,275 222 10 limits of inflammability, a range of abou-t 3 to 1, the air intake in the gas-air mixer being constant. V4 must be controllable over a w-ide range, so that it may be adjusted until only a sli.-ht drip continually comes from the skimmers 18,6. In operation VI and V2 are closed, while V3 and V5 are open. To shunt down, V3, V4 and V5 are closed and V2 is opened. Since at least the end sections are vented through the skimmers, these will drain rapidly and the 10 pump and motor section will follow more slowly. , For starting V2 is closed, VI and V5 are opened wide and V3 partially, while the glowplug is energized. At the first sign of temperature rise in the combustor VI[ is closed, V3 and V4 are opened wide. When the maximum 15 gas pressure is reached, the current to the glowplug is cut off, while V4 is adjusted for the minimum skimmer flow. The compressed gas and air issuing from the pumps are delivered to two separators, where the water is collected and made to join the stream of cooling water coming from 20 the jet pump. The gases reach the combustor separately, to be mixed after ignition. The cooling water mixed with the sealing water from the pumps, goes thr@ugh the radiator part of the condenser. The Freon-water mixture goes straight to the con25 denser, whereupon the liquids are separated by gravity as shown, the Freon being about 50% heavier than water. From here the water is mixed with the stream coming from the radiator to be returned to the motor as cooling water. The liquified Freon goes via the capillary tubes to the 30 evaporator, where it abstracts heat from the air stream pumped over the coils by the circulating fan. After vaporization it returns to the Freon pump. FIG. 33 shows a liquid piston engine with an output shaft for multiple V-belt drive. The motor side of the 35 housing 192 and rotor differ from those of the machine shown in FIG. 6 only, in that the roller bearing 68 and the oil seals 71 and 73 have been replaced by a ball bearing 193 and the oil seals 194 and 195. This means that a modified bearing retainer 196 and bearing housing 40 197 are needed, but the motor wheels 74 and 75 remain unchanged. Also the cover 52, the ring 185 and the spacer ring 163 are the same as before and so are the gas, air and exhaust collector rings, the gas distributing ring, the nut 58 and spacer 161, but the product gas dis45 tributor inlet 198 was modified for clearance. However, except for the air entrance 199, all gas in- and outlets were moved to the motor side. The pump side now contains only the impeller for the gas pump 200 and for the air pump 201. Also the bear50 ing housing was changed to a housing 202, which contains only the oil seal 203 and has been adapted for attachment of the flange 204 of the output shaft 205. This shaft is supported by two ball bearings 206 and 207, mounted in the housing 208, which also serves as end 55 cover for the stator housing 192 and supports a skimmer 209 for draining excess water via the hole 210 and the outlet 211. Bearin- 207 carries a snapring 212, which locates it axially between the housing 208 and its cover 213. The shaft 205 carries the sheave 214 having a hub 215. 60 The nut 216 clamps this hub, the inner race 217, the spacer 218 and the inner race 219 against the shoulder 220 on the Range 204. The shaft further has an extension 221, provided with groove for the snapring 222 to retain the pilot bear65 ing 223, which fits in the counterbore 224 in the spindle 225. Thus on the pump side the spindle is indirectly supported by the end cover 208. The water and gas passages in the spindle have been altered to fit the new organization of parts. FIGS. 3;5 70 through 43 show the new arrangement and it will be seen that FIGS. 37, 38, 40 and 43 correspond respectively with FIGS. 10, 11, 15 and 12. Further FIGS. 36, 39 and 41 show two different ways of fumishing water under pressure to the critical areas. The last two duplicate the 75 method of FIG. 29b, but in FIG. 36 only the hole 226

has been drilled, while the slot 227 substitutes for the holes 228 or 229. It will also be noticed that three pairs of holes 230, 231 and 232 have been drilled in an axial direction froin the end face 233 of the spindle in the rnetal outside of the pilot bearing 223. All six of these have been plugged at the end face. Of these 230 and 231 run until they meet 229 and 226 at station 41. Both pairs pass small cross drills at the end partition of the housing 202 and serve for the purpose of sealing the crititical areas in this partition. The sealing water comes from the supply at station 41. The holes 232 break into the air intake ports 234 of the air pump. They pass cross drills between the two contact lips of the oil seal 203, thus reducing the pressure in the space between these lips to atmospheric, with the result that any air or water entering this space is eliminated. The hole 235 in FIG. 35 performs the same function for oil seal 195 by venting it into the gas intake so that any water bleeding through with the air may @, recovered. Holes 9 and 17 in FIGS. 6, 9 and 17 are there for the same reason. The water circulation eastings 236 and 237 also differ from those used before. Cooling water enters at 238, flows into the cavity 239, from where it enters the pipe 240. It retums via the holes 241 and the annulus 242 and leaves the unit 236 at 243. Make-up water enters at 244, passes through the hole 245, from where it enters the tube 246, which at the end is closed off by the plug 247 with the orifices 248, from which it squirts in the direction of the air intake ports 234. T@he water ciculation castings are separated from each other by the gasket 249 and from the spindle by a gasket 250 that seals all openings for the gas passages, except water and stud holes. The water drain system of the machine of FIG. 33 is the same as that of FIG. 6. The method of starting may be the same as described for the motor-refrigerant pump, or it is possible to utilize a conventional automotive electric starting system together with low pressure water injection. While two embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise, withotit departing from such principles. It must be pointed out th-,it the very low pressure used for the refrigeration condenser is a function of the refrigerant chosen and by no means the limit of the liquid piston machine. Liquid piston pumps have been used to compress air to 100 p.s.i.a. using water as the liquid. Much higher pressures can be obtained by double staging or using heavy liquids, such as acetylene tetrabromide, mercury and others. In the appended claims the following definitions apply: An IMPELLER is a disc associated with a pump carrying equally spaced, axiallyprotruding vanes. A WHEEL is a disc associated with a motor carrying equally spaced, axially protruding vanes. A ROTOR is the assembly of all impellers, wheels and other rotating parts supported by two or more bearings. Outside and inside surfaces of the rotor are concentric with its centerline of rotation. A STATOR SPINDLE is a stationary cylindrical shaft having an outside diameter sized to slide inside the rotor. At the location of each impeller or wheel the outside surface is provided with intake and exhaust ports, which are depressions each communicating with one of several longit.udinal passages inside the spindle. The spindle is further provided with bearings to support the rotor. -ECCENTRICITY is the distance between the centerline of the rotor and-the centerline of a cylindrical segment on the housing; Theeccentricity is positive or negative, -dependent o,@i wbetber ihe centerline and the segment 3,275,222 12 are on the saine or on opposite sides of the centerline of the rotor. A LOBE is a cylindrical segnient having a centerline with positive eccentricity. 5 A FLANK is a cylindrical segment having a centerline with zero or negative eccentricity. The rotor always approac@hes the midpoint of a flank within running clearance. A STATOR HOUSING is a stationary housing surround10 ing the rotor. The cente@rline of housing and rotor coincide. Wherever there are wheels or impellers on the rotor, the cross section of the housing is composed of equally spaced identical lobes, halfway between which there are identical flanks. The end sections of 1,5 the housing may have round cross sections concentric with the rotor. At the transitions between end, wheel and impeller sections, the hbusing has radial partitions bored out to ,permit rotation of the rotor. A LIQUID RING is a layer of liquid on the inner sur20 faces of the sta@tor housing accumulated under the influence of a centrifugal force field caused by the rotation of wheels, impellers or other pailts carrying vanes when the stator housing is filled with sufficient liquid to keep the va-@ie tips submerged. 25 A MIXTURE is an inflammable mixture of fual and air. A PRODUCT GAS is a gas composed of the products of combustion of a mixture with or withou-t air dilution. A COMBUSTOR is a device for igniting compressed mixture with a glowplu- or flame holder, combusting it 30 at constant pressure and mixing the products with air. I