US2422789A

US2422789A - Compressor-motor apparatus

Info

Publication number: US2422789A
Application number: US541159A
Authority: US
Inventors: Jr Allen Latham
Original assignee: Arthur D Little Inc
Current assignee: Arthur D Little Inc
Priority date: 1944-06-20
Filing date: 1944-06-20
Publication date: 1947-06-24
Anticipated expiration: 1964-06-24

Description

June 24, 1947.

A. LATHAM. JR

COIPRES SOR -MOTOR APPARATUS 7 Sheets-Sheet 1 Filed June 20, 1944 EZENTORU TTORNEYZ June 24, 1947. A. LATHAM, JR

COMPRESSOR-MOTOR APPARATUS Filed June 20, 1944 '7 Sheets-Sheet 2 Je 4, 1947 A. LATHAM. JR

COMPRESSOR-MOTOR APPARATUS Filed June 20, 1944 7 Sheets-Sheet 3 INVENTOR mwmm au BY ATTORNEYS June 24, 1947. A. LATHAM; JR 2,422,789

COMPRESSOR-MOTOR APPARATUS Filed June 20, 1944 7 Sheets-Sheet 4 ATTORNE m? @E. Q m zkwqigli/ -f F M na J... h Q Q m .HFHHLI W W. J

June 24, 1947. LATHAM' JR 2,422,789

COMPRES SOB-MOTOR APPARATUS Filed June 20, 1944 '7 Sheets-Sheet 5 June 24, 1947. A. LATHAM. JR

I COMPRESSOR-MOTOR APPARATUS Filed June 20, 1944 7 She ets-Sheet 6 INVENTOR ;Y X ATTORZEYS Patented June 24, 1947' COMPRESSOR-MOTOR APPARATUS Allen Latham, Jr., Jamaica Plain, Mass, assignor to Arthur D. Little, Inc., Cambridge, Mass., a

corporation of Massachusetts v Application June 20, 1944, Serial No. 541,159

This invention relates to compressor-motor apparatus. It relates especially to compressor-motor apparatus of the rotary reciprocating piston type. r

It is a general object of this invention-to provide compressor-motor apparatus for compressing a gaseous material as a result of mechanical power supplied to the apparatus or for taking oil mechanical power by expansion of a gaseous material supplied to the apparatus. It is a, further object oi. this invention to provide compressormotor apparatus having high eiliciency and high capacity for its size and weight. It is a further object, according to preferred embodiments of this invention to provide compressor-motor apparatus which is operable notwithstanding absence of 111-- bricant in the region of the apparatus wherein the gaseous material comes in contact with the I ly desirable for affording a supply 01 compressed air for any purposes such as operation of one or more compressed air motors. The apparatus is also suitable for compressing a'vapor such as steam or for converting the energy of compressed;

steam into power. When reference is made herein to gaseous material, it is to be understood that 28 Claims. (Cl. 230185) tered. On the other hand, expansion engines for handling combustion gases and the like operate at very high temperatures under which no existing lubricants have been found to besatisfactory. Another advantage of the compressor-motor apparatus of this invention is that it has mechanically-actuated admission and discharge valves. Therefore, no pressure is required for opening these valves and favorable conditions are provided for compression or expansion of gaseous material which is at or near its saturation temperature such as has to be handled in certain invention is operable, thereby providing large cathe reference is to either gases or vapors or mixtures of gases and vapors, the gaseous material being compressible.

The compressor-motor apparatus 101' this invention is of advantage in that it not onlyhas application for uses to which ordinary reciprocating compressor-motors are put, but also under unusual, special and diilicult conditions. One of such special conditions is the supply of gaseous material which is not contaminated with lubricant, and the apparatus oi! this invention is especially advantageous for such purpose. The compressor-motor apparatus of this invention is likewise of great advantage for operation under conditions which involve extremes of temperature at which no known lubricant will function satisfactorily. Expansion engines used for gas liquefaction must operate without lubricant because of the extremely low temperaturesencounpacity relative to the size of the unit, is also of great advantage in the handling ofvapors that are at or near their saturation temperature.

It is a further advantage of the compressormotor apparatus of this invention that it can readily be produced with very small clearance volume in the'compression-expansion space, thus making it adaptable to highly eflicient operation.

The compressor-motor apparatus of this invention can likewise be produced with an unusually high ratio of-port area to piston displacement, which is of advantage in affording 'a device that is operable at unusually high speeds. A further advantage that is incident to the high speed operation of the device of this'invention resides in the fact that the compressor-motor apparatus can be made of unusually low weight and bulk as compared with conventional reciprocating compressors and motors. Moreover, problems of impaired efliciency due to leakage of gaseous materialbeing handled, are reduced because of smaller dimensions of the regions where scaling is tobe effected. I

Notwithstanding the utility of the compressormotor apparatus of this invention under special 'and exacting conditions, it is of further advantage that the apparatus is practical and economical both to construct and to maintain. Thus the surfaces which must operate with close clearances are either cylindrical or flat and therefore There are a number of features of this inven-.

tion which are preferably availed of in combination but which may be availed of separately in The high speed at 3 compressor-motor apparatus of this invention- Before describing the specific embodiments of this invention which are shown in the drawings and described hereinbelow, brief reference will be made to some of the features of this invention.

Certain of the features of this invention relate to the combination of a rotary and reciprocatory rod with a coaxial peripherally cylindrical piston and with bearing means for the rod which fixedly maintains the axial alignment of the rod and of the piston so that the piston may be operated out of pressure-contact with the cylinder in which it operates, thereby avoiding necessity for lubrication between the piston and the cylinder. Th combination of the piston-carryin rod with a power shaft in axial alignment therewith and with an axially slidable means for transmitting rotational power between the shaft and the rod is a further feature of the invention that is of importance in effecting a smoothly-operating continuous rotation of the parts and reciprocation of the piston, especially for high speed operation.

librium of the forces acting on the piston by the gaseous material being handled.

Further features of this invention relate to means interposed between the piston and the reciprocating means for preventing lubricant for the reciprocating means reaching the compression-expansion chamber. In preferred embodiments, spaced bearings for the rotating and reciprocating rod are interposed between the reciprocating means with trap means for the lubricant between these spaced bearing means. Preferably, also, there is a lubricant flinging means carried by the rod that throws lubricant into the trap means. Moreover, in preferred embodiments, one or more bearing means between the reciprocating means and the compression-expansion chamber is mounted on a support which projects inwardly into a housing or chamber so that the device can be operated in any position without having a bath of lubricant contacting such bearing means. Likewise, in preferred embodiments, the inwardly projecting bearing support is surrounded by an inwardly projecting shield or sleeve spaced therefrom and a vent for the space between the shield and the bearing support is provided. The trap means can likewise be connected with the high pressure side of the compressor-motor to prevent seepage of lubricant into the trap means.

Another feature of this invention resides in the provision of an essentially gasproof casing about the reciprocating means and associated motor or-generator operatively connected to the reciprocating and rotatable rod which entraps any gaseous material that may seep past a bearing between the compression-expansion chamber and the reciprocating means so as to build up a back pressure that minimizes such tendency of gaseous material to escape from the compressionexpansion chamber.

Further features of this invention relate to the porting means employed in connection with the expansion-compression chamber and the provision of such porting by means of valve ports in the piston or piston'slrirt for cooperation with inlet and outlet ports of the cylinder in which the piston operates. One such porting arrangement in preferred embodiments includes the provision of diametrically-opposed simple openings in the piston periphery or skirt as valve port means and the provision of pairs of diametrically-opposed simple openings in the cylinder wall which are located for being traversed by the valve port means in the piston skirt so as to control inlet and outletof gaseous material. This construction may advantageously be used so as to provide inlet and outlet ports for the cylinder which are common to compression-expansion chambers on opposite sides of an intermediate barrier or head of a double-acting piston. In such construction utilizing a double-acting piston, it is also a feature of this invention that the barrier or head between the oppositely-extending piston skirts is substantially thinner than the hub for aflixing the piston to the rod.

Another feature of this invention relates to the movability of the normally-stationary cylinder in which the piston reciprocates for reversing the operation of the device. Other features relate to the provision of a plurality of piston means afiixed in coaxial relation with the rotating and reciprocating rod and effecting operative communication between the compression-expansion chambers associated with the pistons. Other features of this invention relate to the provision of first and second reciprocating and rotating rods in 'axial alignment with each other'and causwith the following typical embodiments of this invention which, for illustrative purposes, are described below and shown inthe accompanying;

drawings, wherein Figure 1 is a side elevation, partly in section,

of compressor-motor apparatus according to this invention;

Fig. 1A is a side elevation, partly in section,

, showing the detail of the other end of the device of Fig. 1;

Fig. 2 is a section taken on' the line 22 of Fig. 1, showing the exhaust ports open;

Fig. 3 is a section taken on the line 3-3 of Fig.

Fig. 4 is a section taken on the line 4-4 of Fig. 1;

Fig. 5 is a side elevation of the end of the rotatable and reciprocatable rod and the small piston located at the end of such rod:

Fig. 6 is an end sectional elevation similar to Fig. 2 but showing an alternative cylinder construction that is adapted for rotation to reverse the action of the device;

Fig. 'l is a fragmentary side sectional elevation taken on the line |-'I of Fig. 6;

Fig. 8 is an end elevation of the cam member of the reciprocating means of the device;

Fig. 9 is a horizontal section taken on the line 9--8 of Fig. 8;

Fig. 10 is a vertical section taken on the line lD-ill of Fig. 8;

Fig. 11 is a side elevation of the large piston 15 member of the deviceshown in Fig. 1;

Fig. 12 is a left elevation of the piston member shown in Fig. 11;

Fig. 13 is a right elevation of the piston member shown in Fig. 11; v

Fig, 14 is a developed showing of the travel of a port valve of the piston past the intake port in the cylinder of the device shown in Fig. 1;

Fig. 15' is a developed showing of the travel of a port valve of the piston past the exhaust port in the cylinder of the device shown in Fig. 1;

Fig. 16 is a sectional elevation of an alternative porting arrangement between the valve ports in the piston and inlet and outlet ports of the cylinder; 5

Fig. 17 is a top plan view of the cylinder shown in Fig. 16;

Fig. 18 is a top plan view of the piston shown in Fig. 16;

Fig. 19 is a side sectional elevation of an alternative piston and porting arrangement that may be employed in the practice of this invention;

Fig. 20 is a section taken on the line 20-20 of Fig. 19.;

Fig. 21 is a sectional elevation of an alternative power transfer device for rotating a rotatable and reciprocatable rod;

Fig. 22 is a schematic view of a typical installation of compressor-motor apparatus according to this invention; and

Fig. 23 is a schematic view of another typical of the piston head or barrier 43 are the openended skirts 44 and 45. In the skirt 44 are diametrically-opposed valve ports 46. The skirt 45 is provided with diametrically-opposed valve ports 41 which are at a 90 angle with respect to the valve ports 46' The end of the cylinder 3| is provided with a cylinder head 48 which is fixed to the cylinder 3| as by bolts 49. The cylinder head 48 is provided with a member 50 which is reentrant into the compression-expansion space within the cylinder 3|, which fits within the open-ended skirt and over the hub 4| of the piston and which substantially completely fills the space within the skirt 44 between it and the reentrant hub member 4|. This is clearly shown in Fig. 1 wherein the rod 38 and the piston 40 are moved to the installation of compressor-motor apparatus according to this invention;

A typical embodiment'of compressor-motor apparatus according to this invention is shown in Figs. 1 to and 8 to and comprises a main housing 35 which has the cylinder 5| extending therefrom and integral therewith. The cylinder 3| may advantageously have the fins "protruding therefrom so as to provide extended surface area for the dissipation of heat. With reference to the cylinder 3|, the word cylinder is used as applicable to any member having a cylindrical inner surface adapted for the reciprocation'of a peripherally cylindrical piston therein, without regard. to the shape of theextemal surface and whether the external surface is cylindrical or is of some other shape, such as a square shape, as shown in H8. 2. Within the cylinder there is fitted a cylinder head ll which is reentrant into the compression-expansion space within the cylinder 3|. The cylinder head 33 has a bearing support 44 integral therewith that supports the bearing 35 for the rod 38. The term "cylinder head is used herein whether or not a rod or the. like does, or does not, pass therethrough. Projecting from, and inwardly into, the housing 35 is another'bearing support 35 which supports the bearing 31. The rod is maintained in fixed axial alignment by the bearings and 31 which afford continuous rotary motion and reciprocatory motion for the rod 35. The rod 28 may be either solid or hollow and in the embodiment shown the rod 35 is in the form of a hollow tube.- Ordinarily, it is preferable to use a hollow rod, inasmuch as the weight of the reciprocating parts of the device thereby may be diminished without undue sacrifice of strength.

Rigidly fixed to the rod 35 for rotation and reciprocationtherewith is the piston which is indicated generally in Fig. 1 by the reference character '40 and which is shown in detail in Figs, 11, 12 and 13. The piston 40 comprises a hub member 4| which is reentrant into the compression-expansion chamber within the cylinder. A suitable pin 42 or the like may be,provided for rigidly extreme right osition. In a similar way, the cylinder head 3 fits within the piston skirt 45 and substantially completely fills the space within thepiston skirt 45 when the rod 38 and piston 40 are moved to the extreme left position.

In connection with the apparatus as described thus far, itis to be noted that the rod 38 is maintained in fixed axial alignment by the bearings 35 and 31 and that the rod 38 acts as a guide for the piston so that the piston does not bear against the inner wall of the cylinder 3|. It is preferred to machine the peripherally cylindrical surface of the piston 40 so that it will be maintained in proximity to the inner wall of the cylinder 3| with very close clearance but essentially out-ofcontact therewith. It is not essential, however,

that the piston 40 be completely out-of-contact with the, inner wall of the cylinder 3| and there may be some contact between the periphery of the piston and the inner wall of the cylinder. However, since the rod 38 acts as a guide for the piston, there is no force'which causes the piston to bear against the inner walliof the cylinder. Such mounting of the piston is referred to herein as being a mounting which maintains the periphery of the piston out of pressure-contact with the inner wall of the cylinder. When the periphery of the piston is out of pressure-contact with the inner wall of the cylinder, any minor concording to the structure above described, to rotate and reciprocate the piston 40 within the compression-expansion space provided by the cylinder 3| without the use of any lubricant. Moreover, no piston-rings or the like are required. This, as aforesaid, is of great advantage for certain applications of the compressor-motor apparatus of this invention.

In order to properly control the intake and ex burst from the compression-expansion chamber within thecylinder II, the cylinder 3| is provided with intake and exhaust ports. embodiment shown in Figs. 1 and 2, the intake ports 5| are in the form of simple openings of substantial size, the openings being disposed as a pair, one being diametrically opposedto the other. The exhaust ports 52 are also arranged in a pair, one being diametrically opposed to the other. The intake and exhaust ports are in the form of what is referred to herein as simple open ings, namely, openings which are either round or fixing the hub 4| tothe rod 35. On each side. square or other simple shape but which do not In the have any special configuration for following the travel of the port valves and 41 during the reciprocatory and rotary'movement of the piston within the cylinder. The valve ports 46 and 41 in the piston skirts are referred to herein as the valve means for the purpose of clarity in the description and in the claims and to distinguish from the inlet and outlet ports in the cylinder, although the valving action broadly considered is accomplished by these valve ports in conjunction with the openings in the cylinder which provide the inlets and outlets.

In Fig. 14, the'travel of one of the valve ports 48 past one of the intake ports is shown by indicating one of the valve ports 46 in a plurality of different positions relative to the intake port II. The full dimensions of one oi. the valve ports '46 is shown in solid lines. In position (a), shown in dotted lines, the valve port 46 is just starting to traverse the intake port ii. In position (b), the valve port 46 has been advanced on the intake stroke of the piston and is more fully opened for drawing gaseous material into the compression-expansion chamber. In position (0), the valve port 46 is nearly Completely uncovered and a large part of it is available for the intake of gaseous material in thecompression-expansion space. When the port valve 46 is in the position shown in solid lines, the intake stroke of the.

piston has been nearly completed. In position (d) the port valve 46 is about to leave the intake port 6|, thus sealing the gaseous material in the interior of the compression-expansion chamber.

Referring to Fig. 15, there is indicated the travel of one of the valve ports 46 past' the discharge or exhaust port 52. Since the device of this invention is operable either as a compressor or as a motor the term discharge, which is more common in connection with compressors, is used synonymously with the term exhaust, which'is more common in connection with motors. and both are used synonymously with "outlet." The outlet port is smaller than the intake port and usually is so positioned that in compression the pressure in the compression-expansion chamber will be raised substantially due to the discharge stroke of the piston before the outlet port is opened. By suitable design, the compressor-motor apparatus can be made so as to build up any predetermined desired discharge pressure before the outlet port is opened. It is usually preferable to build up the desired predetermined pressure within the compression-expansion chamber so that it will be substantially the same as the pressure maintained at the outlet port before the outlet port is opened. When the valve port 46 is in the position shown in solid lines in Fig. 15", the outlet port 52 has just become opened. As the piston continues to move to the right on the discharge stroke of the piston while revolving, the port valve 46. will occupy the positions (e) and (I) which are shown in dotted lines before,the travel of the valve port 46 past the outlet port 52 has been completed.

The travel of the port valve 41 past the inlet and outlet ports is essentially the same as that described in connection with Figs. 14 and .15 but in the opposite direction. It is to be noted that 38 than the valve ports in the piston skirt, this construction contributing to the rapidity with which the compression-expansion pace may be filled and to the reduction of the clearance volume between the piston and the cylinder heads. It is preferable that the piston skirt be provided with diametrically-opposed valve ports and that one pair of inlet ports and one pair of outlet be noted that the inlet ports havesubstantially greater angular extent about the axis of the rod the inlet and outlet ports in the cylinder be arranged in the form of pairs of diametricallyopposed openings. In this way, the radial analysis of forces due to incoming and outgoing gaseous material may be reduced substantially to zero about the axis of the rod 38. a I

The rod 38 is actuated by means of a power shaft 53 which may be the power shaft of an electric motor. The end of the power shaft 53 is provided with a spline stub 54 which is slidable telescopically within the spline connection 55 at the end of the rod 88. In this manner, the power shaft 53 is rotatable and will cause the rod 88 to rotate while permitting the rod 38 to reciprocate. Similarly, a reciprocatoryand rotary motion of the rod 38 will cause thepower shaft 68 to rotate when the device is being used as a motor.

Fixed to the rod 88 is the cam member which is indicated generally by the reference character 56 and which is provided with an undulatory annular ring 51 which has on each side thereof complementary cam track 58 and 58 (see Figs. 8, 9 and 16) Carried by the interior of the housing 30 are fixed cam guide means in the form of guide rollers 59. There is one pair of guide rollers 59 with each roller directly opposite the other on each side of the cam ring 51 and another similar {sir of am rollers 59a that is diametrically opposed to e pair of rollers 59. In this manner, the forces acting on the cam member are axially balanced with reference to the axis of the rod 38. If desired, more than two pairs of cam rollers may be used when the cam is designed to provide more than, two reciprocations of the piston per revolution, but in any case it is preferable, according to this invention, to have the cam rollers disposed so that their action on the cam" will be axially balanced with reference to the axisof the rod 38. Thus the forces acting on the cam are in alignment with the axis of the rod and there is virtually no thrust of the rod against either of the bearings 35 and 31.

It is to be noted that there is a small chamber 60 between the bearings 35 and 31 which acts 'as a trap for any lubricant which may pass the bearing 31 from the housing 30 for the cam, the cam guide rollers and the spline connection with the power shaft. The parts just mentioned which are within the housing 30 are preferably operated to prevent such lubricating oil from reaching the parts of the device that are in contact with the gaseous material being handled, and, by the provision of the trap chamber 60, any such lubricant is trapped before it can reach the bearing 85. It is preferable, in order to prevent any lubricant from traveling along the rod 38, to afilx to the rod 2, lubricant-flinging member 6| which effectively prevents lubricant fromtraveling along the rod beyond this lubricant-flinging member. If

desired, the lubricant trap'60 may be provided with a drain 62 so that any lubricant collected in the trap 60 can be drained off through the drain 62 and line 63, valves I55 and I56 being open and valve I57 in line I58 being closed. However, the amount of lubricant that is collected in the trap 50 is very slight and, if desired for certain applications of the'device, the drain 52 may be omitted or valve I55 closed. By providing a drain 52 open to the atmosphere, the pressure in the lubricant trap 80 is maintained at atmospheric pressure which is normally less than the pressure of the aseous material in the compression-expansion space within the cylinder 3i. This pressure differentlal thus maintained acts as a further preventative for any seepage of lubricant past the bearing 35 in the direction of the compressionexpansion space.

When, on the other hand, the drain 52 is omittea or the valve I55 is closed, there is a tendency for gaseous material to seep past the bearing 35 from the compression space within the cylinder 3I so as to prevent seepage of lubricant toward the compression space from the trap 50 and so as to build up pressure in the trap 60, which pressure, in turn, urges any lubricant tending to seep past bearing 31 from the cam housing back into the cam housing especially when the cam housing is vented to the surrounding atmosphere or is otherwise maintained under a pressure that is.

lower than the pressure maintained in the trap 50. If desired, the pressure in trap 60 can be positively maintained as by closing valve I56 and opening valves I55 and I51. the valve I51 being in line I58 which leads to the high pressure side of the compressor-motor, e. g., to the discharge line when the device is used as a compressor (se Fig. 22).

It is a further feature of the construction shown, that the support 35 for the bearing 31 projects a substantial distance into the housing 30. Such construction prevents the bearing 31 from being operated in contact with a bath of lubricant regardless of the position in which the compressor-motor apparatus is disposed. Similarly, the cylinder head 33 is provided with the reentrant support 34 for the bearing 35 so as to prevent any lubricant entrapped in the lubricant trap 60 from reaching the bearing 35 regardless of the position in which the compressor-motor apparatus is used. Preferably the bearing support 36 is surrounded by a sleeve or shield member II which is of circular cross section and which is spaced from the support 35. The space between the bearing support 36 and the sleeve I5! is provided with a vent I52 so that the housing for the cam member may be maintained at a pressure lower than the pressure maintained in the trap 60 for the purpose explained hereinabove, the plug I53 for the vent I52 in such case being removed. The purpose of the sleeve I5I is to prevent any lubricant from escaping through the vent I52 when the device is up-ended (the right end being at the bottom) and for this reason the right hand end of the sleeve is secured tightly to the main housing 30 so that no lubricant will flow by it out of the trough I54 where lubricant will collect if the device is thus up-ended.

For certain applications of the compressormotor apparatus of this invention, it is desirable to build up pressure in the region of the powertransfer mechanism, including the spline connection and the cam mechanism, so as to minimize any tendency of gaseous material to seep past the bearing 35 from the compression-expansion space toward the power transfer mechanism. In such case, the drain 62 for the lubricant trap 50 is either omitted or the valve I55 is closed and the vent I52 is omitted or provided with a suitable plug I53. The power-transfer mechanisms are also provided with an over-all casing 64 which be, of which the power shaft 53 is a part. The

casing 64 is secured to the housing 30 as by bolts 55, and packing material 66 is provided'so that there is an essentially gas-proof casing means about the mechanisms with which the rod 38 is operatively connected. By such construction, if there is a. gradual'seepage of gaseous material from the compression-expansion space within the cylinder 3|, past the bearing 35 and past the bearing 31, such gaseous material will gradually build up a back pressure, with the result that, when the back pressure has been increased sufllciently, the tendency for further seepage of gaseous material past the bearings 35 and 31 will be counterbalanced.

It is a further advantage and feature of this invention that a plurality of piston members can be carried on a single rod that is arranged for rotation and reciprocation. A simple form of secondary piston is illustrated in the drawings. In the device shown in Figs. 1, 3, 4 and 5, the rod 38 is hollow and a secondary piston may be readily provided by recessing a. substantial distance from the end thereof a piston head 81 which is rigidly carried on the interior of therod 38 which protrudes beyond the piston head 61 as a piston skirt 68. The head 48 for the main cylinder 35 has integral therewith a secondary cylinder 59 in which the piston skirt 68 reciprocates. The end of the cylinder 59 is provided with a head 10 which has a reentrant member N that fits into the open-ended. piston skirt 68. The cylinder 69 is provided with a pair of diametrically-opposed inlet ports 12 and with a pair of diametrically-opposed outlet ports 13. The piston skirt 68 is provided with a pair of diametrically-opposed valve ports 14. The intake and exhaust are controlled by the inlet ports 12 and the outlet ports 13 and by the valve ports 14 in the same manner as has been described hereinabove in connection with the larger or main piston and surrounding cylinder.

In Figs. 6 and 7, optionally-employed means are shown for reversing the action of the compressor-motor. The rotatable and reciprocable rod 38, the piston 45, and the cylinder heads 33 and 48 are the same as described above in connection with Figs. '1, 2, 11, 12 and 13. The cylinder 3| is also the same except that it is cylindrical exteriorly aswell as interiorly and except that it comprises a port sleeve 12' which provides part of the cylinder that surrounds the piston. The port sleeve is provided with a pair of diametrically-opposed inletports 13 to which the inlet lines 14 are secured. The port sleeve 12' is likewise provided with a pair of diametrically-opposed outlets 15 to which the outlet lines 15 are secured. These inlet and outlet ports and lines co-operate with the valve ports in the piston skirt in the manner hereinabove described. In the construction shown in Figs. 6 and 7, however, the port sleeve is rotatable about the axis of the rod 38 so that the relative angular position between the cam and cam guide means, on the one hand, and'the inlet and outlet ports in the port sleeve, on the other hand, can be changed. By turning the port sleeve 12' about and adjusting it to desired position, it is apparent that the inlet port will be where the exhaust port formerly was and that the exhaust port will be where the inlet port formerly was. Therefore, what was formerly the exhaust line becomes the inlet line and. what was formerly the inlet line becomes the 11 exhaust line. If the device is being used as a compressor, the direction of action of the compressor will be reversed. If the device is being used as a motor with the gaseous material under pressure being forced in through the same line at all times, the direction of rotation of the rod 38 will be reversed.

In Figs. 1 to 15, the preferred arrangement of valve-controlled inlet and outlet means for the compression-expansion chamber has been described. Such porting arrangement i preferred, not only because it provides both hydraulic and dynamic balanceof the action of the gaseous material on the piston and relative to the axis of the rod, but also because it enables the port areas to be of large size and permits small clearance volume between the piston and the cylinder heads. By the arrangement shown, the clearance volume can thus be reduced virtually to the capacity of the valve ports in the piston. Since these valve ports are in the form of simple openings that extend directly through the piston skirt, the clearance volume is very low. By utilizing only a single port valve in the piston, the clearance volume can be reduced to an extremely low value, but by so doing the hydraulic balance of the forces of the gaseous material acting on the piston is sacrificed. As distinguished from simple ports in the piston skirt which extend directly through the piston skirt, elongated ports or channels in the piston, if used, tend to increase considerably the size of the valve port means that communicates between the compression-expansion chamber and the inlet and exhaust ports which in turn increases considerably the clearance volume and reduces the efl'iciency of the apparatus. In addition, the preferred arrangement of valve-controlled inlet and outlet port means permits the employment of ports and valves of high flow capacity so that the filling and emptying of the piston is very rapid, thereby permitting high speed operation.

While a preferred arrangement of valve-controlled inlet and outlet ports has been described above, other porting arrangements may be employed in connection with compressior-motor ap- Daratus embodying this invention. One such alternative porting arrangement is shown in Figs. 16, 17 and 18. The rod 38 shown in these figures may, for example, be rotated and reciprocated in the manner that has been described hereinabove and carries, in fixed relation thereto, the piston which is indicated generally by the reference character I83. The piston I83 has a central head I8 from which a hub 19 protrudes for establishing firm union with the rod 38. From each side of the head 18,-the open-ended piston skirts 88 and 8! extend. These piston skirts are peripherally cylindrical and are coaxial with the rod 88 and are surrounded :by the cylinder 82. The cylinder 82 is provided with a head 88 having a reentrant member 84 that is adapted to fit within the skirt 88. At the other end, it has 9. head 86 having a reentrant member 88 that is adapted to fit within the skirt 8| and likewise is adapted to fit over the hub 19. The cylinder is provided with the inlet ports 81 and 81 and opposite thereto with

outlet ports

88 and 88. The line of travel of the inlet ports 81 and 81' along the periphery of the cylinder skirts traverses the

openings

89 and 89 which are on diametrically-opposite sides of the piston skirts. The outlet ports 88 and 88' do not follow the same line of travel along the piston wall and do not traverse the valve port openings 89 and 89' but do traverse the valve port openings 98 and 98' which are disposed in diametrically-opposed pairs.

While the porting arrangement shown in Figs. 16, 1'7 and 18 is suitable, it may be noted that the valve port openings 89, 89' and 98, 98' are not simple openings but are elongated and are curved slightly to follow the inclination of the cam track of the cam means for reciprocating the piston. Since these openings are considerably larger than is necessary to provide a port of similar flow capacity using the embodiment of this invention shown in Figs. 1 to 15, the resulting clearance volume is correspondingly greater. Moreover, it is usually desirable, in order to afford more free flow of gaseous material to and from the compressionexpansion chambers, to provide the recesses 8I and 93 in the reentrant member 84 of cylinder head 83 adjacent the exhaust port 88 and the inlet port 81 respectively, and corresponding recesses 92 and 94 in the reentrant member 88 of cylinder head 85 adjacent the exhaust port 88' and the inlet port 81' respectively. Such recesses further increase the clearance volume of the compression-expansion chambers.

When very low clearance volume is not essential, one can, in the practice of this invention, dispense with the skirted piston constructionv and can employ a simple peripherally cylindrical piston having valve ports in the side wall thereof. Such an alternative embodiment of this invention is shown in Figs. 19 and 20. The rotatable and reciprocatable rod 38 may be as described hereinabove. Secured to the end of the rod 38 is the solid piston 95 which has diagonal drillings 96, 96' taken from one end thereof and which provide simple valve ports in the side wall of the piston that are diametrically opposite. On the other side of the piston are similar drillings 91, 9'! located at a 90 angle with respect to the drillings 88, 98'. Surrounding piston 85 is the cylinder 98 which is provided with cylinder heads 99 and I88. The cylinder 98 has a pair of diametricallyopposed inlet ports I8I and a pair of diametrically-opposed outlet ports I82. These inlet ports and outlet ports correspond with the inlet ports BI and 52 in the embodiment of this invention shown in Figs. 1 to 15 and are traversed by the valve ports provided by the

drillings

98, 96 and 91, 91 in the manner that has been described hereinabove in connection with Figs. 1 to 15. However, it is apparent that the drillings 98, 98 and 91, 91' increase the clearance volume in their respective compression-expansion chambers. The construction shown in Figs. 19 and 20 is also less desirable, especially for high speed operation, since a solid piston weighs considerably more than a skirted piston of the character hereinabove described. By use of a skirted piston and by the employment of a thin piston head in combination wltha hub of substantially greater extent along the axis of the rod than the piston head, a sturdy construction is provided and at the same time the reciprocating parts can be made of very light weight, which is advantageous.

An alternative power-transfer means for providing an axially slidable connection between the rotatable and reciprocatable rod and the rotatable power shaft in axial alignment therewith is shown in Fig. 21. The rotatable and reciprocatable rod 38 may be according to any of the preceding embodiments of this invention. The rod 38 carries a cam member I which may be generally similar to the cam member shown in Figs. 1, 9, 10 and 11 and which cooperates with appropriate guide Fixed to the end of the the rod 88, is the cross bar I81 which has drive pins I08, I08 that project therefrom parallel to the rod 38 and that fit telescopically into the holes I09, I through the cross bar IIO of the cam member I05. If desired, a guide pin III, which is coaxial with the shaft I and the rod 38 and which fits telescopically within the hole III that is also axially aligned, may be employed to assist in maintaining the shaft and rod in axial alignment. With the construction shown, the power shaft I06 will rotate with the rod 38 while permitting reciprocation of the rod 38. Powertransfer means such as that shown in Fig. 21 is particularly useful under heavy load conditions.

In Fig. -1 of the drawings, only one end of compressor-motor apparatus is shown in detail. The opposite or left hand end of the device is shown in detail in Fig. 1A and is shown diagrammatically in Figs. 22 and 23. In Fig. 1A the parts of the mechanism have, for purposes of brevity, been indicated by the same reference characters as the parts shown in Fig. 1- except that a prime is associated with each of the reference characters shown in Fig. 1A. In the device shown, the parts shown in detail to the right of the power shaft 53 are shown repeated in all respects to the left of the opposite end of the power shaft 53 except that the cam means for reciprocating the rod 38' is arranged to effect motionthat is complementary to the motion of the rod 30. In other words, both rods, which are in axial alignment with the power shaft, are rotated at the same speed as the power shaft and both rods move outwardly simultaneously and at the same rate and to the same extent and then move inwardly simultaneously and at the same rate and to the same extent, the rods being of the same weight and carrying parts of the same weight. In this manner, the inertia forces of the reciprocating rods and of the reciprocating pistons, which are identical, counteract and minimize vibration. While the moving parts at opposite ends of the device can be arranged in this way so that the inertia forces of the moving parts at one end of the power shaft complement or substantially counteract the inertia forces of the moving parts at the opposite end of the power shaft, this can be accomplished in other ways since the inertia forces exerted by the moving parts, for any fixed rotational speed, are a function of the length of the piston stroke and the weight of the moving parts. .It is apparent, therefore, that the weight of the moving parts and the stroke of such parts at opposite ends of the power shaft can be adjusted so that while the weight and stroke may individually be different, the inertia forces of the parts at the opposite ends of the power shaft will be the same or will substantially counteract each other and thereby minimize vibration. In addition to counteracting the inertia of the moving parts, the intake and discharge occur simultaneously and the forces due to the gaseous material handled by the cominvention may be made of any suitable size.

under pressure, such as steam, hot combustion gases, or the like, is introduced into the compression-expansion chambers associated with'the pistons. However, in such case the inlet means for the gaseous material under pressure in such case is the same as the outlet means for gaseous material when the device is used as a compressor. Upon the introduction of the gaseous material under pressure, the expansion of the gaseous material causes the pistons to reciprocate and the reciprocation of the pistons causes the rod 38 to rotate as it reciproc-ates, the rotary motion of the rod 38 being transferred to the power shaft 53. In such case, the motor generator II3 may act as a generator for electric power, the electric power being taken off through the lines Ill and II5. Since the power shaft 53 may be connected either with a motor or with a generator, depending upon whether the device is used as a compressor or as a motor, the term motor-generator" is used broadly herein and in the claims as referring to a device which may act as a motor but not as a generator, or which may act as a generator but not as a motor, or which may act either as a generator or a motor. In the ordinary ease, the motor-generator is electrical, but this is not essential and the power shaft 53 may be comprised in any device which is adapted to supply power to the shaft 53 or which is adapted to be driven by the shaft 53. When the apparatus of this invention is used as a motor, it is usually desirable to employ some inertia wheel or the like which can, for example, be carried by the power shaft. In th device shown, the rotating parts of an electric generator will act suitably as-an inertia wheel.

Compressor-motor apparatus embodying this It is an advantage of this invention that the com- 'pressor-motor apparatus may be made of relatively small size and of a very compact character. Compressor-motor apparatus of this invention may be made small and compact so as to be capable of supplying from about one-half to fifteen cubic feet of air per minute compressed from atmospheric pressure to about five to twenty pounds per square inch. In a small-sized unit of this character, the unit can be operated at relatively high speed, such as 1700 to 3450 R. P. M. Even considerably higher speeds are also possible. The device can be made in larger sizes and can readily handle a thousand or more cubic feet per minute. When the device is made so as to be of large capacity, the rate of operation is ordinarily somewhat lower than mentioned above, due to the greater inertia of the moving parts. While the compressor-motor apparatus of this invention is capable of operating at relatively high speeds, it does not necessarily have to be operated at such speeds and can be operated at slower speeds which are more conventional for reciprocating type mapression-expansion chambers at the opposite ends.

of the compressor-motor apparatus counteract, which likewise minimizes vibration. In Figs. 1 and 1A, the power shaft 53 is show as comprised in an electric motor-generator II3 which is provided with suitable electrical conducting lines Ill and II5 leading to the exterior of the casing 54. When the device is being used as a compressor, the motor-generator II3 acts as a .motor, and, by supplying power to the power shaft 53, imparts reciprocatory and rotary motion to the rod 38 and to the pistons carried thereby for the compression of a gaseous material. when the device is used as a motor, gaseousmaterial chinery. The fact that the compressor-motor apparatus of this invention operates with high efllciency at speeds of the order 1700 to 3600 R. P. M. permits direct connection of the compressor, motor apparatus of this invention to standard units such as electric motors that operate at such speeds, whereas conventional devices operate through belting or gearing with the exception of diaphragm type compressors which have very limited capacity (not over.about two cubic feet per minute) and are disadvantageous for other reasons which have been mentioned hereinabove.

In a single stage of'the compression, it is usually not desirable to attempt to change the pressure of the gaseous material handled by the apparatus more than about four times if good emciency is to be maintained. Where a greater ratio of compression or expansionis desired, then the compression or expansion can take place in a plurality of stages. Thus, in two-stage compression, for example, using the device of this invention, one can readily maintain an exhaust pressure of 225 pounds per square inch usingtwostage compression from atmospheric pressure.

In Fig, 22, a typical installation is shown' utilizing compressormotor,apparatus embodying this invention. The device, as shown, is adapted for use as a compressor in the compressing of air to which a. certain amount of water vapor is to be added. The air is taken in from the atmosphere at the filter inlet H6 which is provided with an atomizer I I1 that causes droplets of water to be entrained in the incoming air. The air stream is divided and flows through lines H8, H9 to the inlet ports which may, for example, be the inlet ports 5| 0! the mechanism shown in Fig. 1. The air is compressed in the apparatus and flows from the apparatus through lines I20,

I2I which are connected to the outlet ports 52. During compression, the droplets of water entrained in the incoming air will tend to become pressed air plus vapor that is discharged under elevated pressure is substantially greater than would be the case it dry air only were being compressed. If only one stage of compression is desired, the small auxiliary piston 61 at the end of the rod 38 may be dispensed with, or cut oil by closing valve I25, and the compressed air and vapor directed for flowing out through line I22, the valve I23 being open. As aforesaid, it I is preferable to simultaneously operate in complementary relation compressor apparatus according to this'invention which comprises two essentially similar and complementarily-acting units located in axially aligned position at opposite ends of a power shaft of a power supply unit or the like. In Fig. 22, the inlet and exhaust lines of such complementary compressor unit are shown, the reference characters H6, H1, H8, H9, I20, I2I, and I23 having the same significance as the reference characters H6, II1,-4,I8, H9, I20, I2I and I23 respectively. When the device is arranged in this manner, the gaseous material compressed by the two complementarily-disposed units will flow into the line I22 and be directed to a common discharge line I24.

When it is desired to maintain the trap 60 under pressure, the discharge line I20 may be connected thereto by line I58, the valves I51 and I55 being open and the valve I58 being closed as mentioned above in connection with the description of Fig. 1.

When multi-stage compression is desired using the device. shown in Fig. 22, valve I23 may be closed and the valves I25 and I26 opened. The valve I25 is in the line I21 which is divided so as to have two portions I28 and I29 which lead to the intake ports 12 of the device shown in Fig. 1. The valve I26 is in line I30 which has arms I3I and I32. that are connected to the exhaust ports 13 of the device shown in Fig. 1. Corresponding 16 valves and connecting lines I25. I26, I21, I28, I29, I30, I3I, and I32 may be located at the opposite end of the compressor-motor apparatus.

A device such as that shown in Fig. 22 may, for example, be used to supply air under pressure and containing vapor to a combustion chamber of an engine where it is united with combustible material and subjected to combustion. By increasing the pressure and/or volume of :the compressed gaseous material, it is possible to recover the power by directing the combustion gases through an expansion engine. The device 01 this invention is admirably suited as an expansion engine. Thus, referring to Fig. 22, the hot combustion gases can be introduced through the line I24 (line I24 in such case being the inlet when the device is used as a motor, instead of being an outlet when the device is used as a compressor). The hot combustion gases can be permitted to expand in one stage or two stages using the connections that have been described hereinabove', causing the rod 38 to reciprocate and r0- tate, the rotation of the rod 38 being transferred to the power shaft 53 for driving an electric generator or any other mechanism that is to be supplied with power.

It is anadvantage of the device of this invention that it is capable of handling the hot combustion gases without the necessity for a lubricant in the compression-expansion chambers of the device. As has been mentioned above,

handling hot combustion gases has heretofore presented great difliculty due to the fact that no lubricant is known which is capable of standing up under the extremely high temperatures at which hot combustion gases are supplied for expansion in an expansion engine.

In Fig. 23, another typical installation is shown of compressor-motor apparatus embodying this invention. In the installation shown, the apparatus is used as a compressor in a system which is maintained at super-atmospheric pressure and in which a supply of compressed air is furnished for operating an expansion motor. Compressors for supplying compressed air are extensively used in aircraft operation for the actuation of various instruments, the system as a whole being operated at super-atmospheric pressure. Super-atmospheric pressure is maintained in order to avoid non-uniform actuation of the instruments resulting from differences in atmospheric air pressure at different altitudes. In Fig. 23, a compressor of the type shown in Figs. 1 and 1A may, for example, be employed in such a system. The air under pressure that is discharged from the compressor is directed through lines I33 and I34 to the high pressure line I35. An instrument to be I operated is indicated schematically by the referorder to compensate for leakages from the closed system, the smaller or auxiliary piston may be used to feed a desired amount of additional compressed air into the system. The air is taken into the auxiliary piston by the lines I40 and I which lead to the inlet ports 12 of the compression chamber of the auxiliary piston. The exhaust ports 13 of the compression chamber of the auxentrained lubricant.

17 iliary piston are connected to lines I42 and I43, the latter line feeding into the line I39 which is on the low pressure side of the main compression-expansion chamber of th apparatus. In order to prevent excessive pressure from building up within the system, the instrument I 36 may be provided with a, relief valve I59 whichpermits escape of gaseous material above a predetermined constant pressure to be maintained.

When the compressor-motor apparatus is made so that the compressor portions thereof are duplicated on opposite ends of the central power shaft, the two units may, if desired, b arranged in :parallel. The lines of the second unit have been indicated by the reference characters I33, I34, I38, I39, I40, I4I', I42 and I43. When both compressor portions of the apparatus are operated in parallel, the valves I44 and I50 are in open position with the valve I45 in the line I46 in closed position. Under such conditions of operation, the valve I41 .in 'line I48 is also closed and the valve I49 in line I42 is open. If desired, the compressor portions of the apparatus may be operated in series, thereby operating the instrument I36 at a greater pressure differential than is the case when the compressor portions of the apparatus are operated in parallel. This can readily be accomplished by closing the valves I 44, I49 and I50 and opening the valves I45 and MT. In such case, the air discharged from exhaust lines I33 and I34 is taken to intak lines I38 and I39 for further compression, and the exhaust from the second compression stage and under increased pressure is taken through exhaust lines I33 and I34 and thence to the instrument I36. All of the supplemental air that is fed into the system is'taken to line I39 by the line I42 and by the lines I42 and I48,'namely, to the low pressure side of the compressor which effects the first stage of compression.

The use of a compressor embodying this invention is especially desirable in connection with an installation such as that shown in Fig. 23. It is important in supplying compressed air for operating the instruments of an airplane, for example, that the air be essentially free from any Iflubricant is carried in the, air supplied to the instrument, it tends to become condensed on the instrument panels and in the instrument machinery, so that frequent cleaning is necessary. When a compressor according to this invention is used, it is possible to compress air and supply it to an instrument without causing the air to come in contact with any working parts of the apparatus on which lubricant is used. Compressor-motor apparatus embodying this invention is also desirable as the supply of compressed air for the instruments of airplanes, since the apparatus is compact and light in weight and has a high capacity for its size and weight. It has been general practice heretofore to operate instruments on airplanes using a compressor of the sliding vane type, but such types of compressor have the disadvantage of requiring lubricant in the compression space'and in contact with air being compressed, for without lubricant such compressors operate with excessive friction and resultant low efliciency, excessive wear and accomplish only very limited degree of practical pressure increase. While compressors of the flexible diaphragm type may be used with-' out lubricant in the compression space, it is necessary to use conventional valve mechanisms which do not operate efficiently due to the rapidity of the pulsations of the diaphragm and frequently greatly affected by variations in the discharge pressure that is maintained.

It is apparent from the foregoing that the compressor-motor apparatus is advantageous for a wide variety of uses and purposes and is of special and peculiar advantage under special conditions of operation under which other types of compressors are either inoperable or much less desirable. While proposals have been made heretofore for providing machinery wherein a piston not only reciprocates but also has at least some rotary motion, such prior proposals have had such serious disadvantages that commercial production, if carried out at all, has been extremely limited. According to the present invention, the features and combinations described hereinabove and recited in the appended claims result in decided improvements upon prior compressor-motor apparatus and have proven of great practical advantage and utility when tested under varying conditions including the exacting and special conditions mentioned hereinabove.

While the compressor-motor apparatus of this invention has been described in connection with certain typical embodiments thereof, it is apparent that this has been done merely for the purpose of illustration and that the construction may be considerably varied without departing from the scope of this invention. Thus, while the apparatus above described affords two intake and exhaust strokes of the piston for each revolution of the rod to which the piston is affixed, it is apparent that the reciprocating means can be varied to provide other numbers of intake and exhaust strokes of the piston for each revolution of the rod. Moreover, other modifications in the compressor-motor apparatus may be made without departing from the scope of this invention as defined in the following claims.

I claim:

1. In a compressor-motor of the character de- I axial alignment of said rod and to afford longitudinal and rotational movement of said rod, a rotatably mounted power shaft in axial alignment with said rod, power transfer means between said shaft and said rod adapted to aiford simultaneously continuous rotary motion of said shaft and reciprocatory and continuous rotary motion of said rod, a peripherally cylindrical piston fixed to said rod in coaxial relation thereto, a cylinder surrounding said piston and coaxial therewith and arranged for reciprocation of said piston therein, the peripheral wall of said piston being in close proximity to the inner wall of said cylinder and maintained out of pressure-contact therewith'by said bearing means for said rod,

. chamber means which includes surface of said means, an outlet for said chamber means, inlet valve means for controlling said inlet, and outlet valve means for controlling said outlet, said inlet and outlet and said inlet valve means and said outlet valve means being arranged to successively direct ingress of gaseous material into said chamber means and egress of gaseous material from said chamber means during the intake and discharge strokes respectively of said piston in said cylinder.

2. In a compressor-motor of the character described, the combination comprising a rod, fixed bearing means arranged to fixedly maintain the axial alignment of said rod and to afford longitudinal and rotational movement of said rod, cam means interposed between said rod and a fixed member for reciprocating said rod upon continuous rotationof said rod, said cam means com-- prising a continuous undulatory cam track and a plurality of cam guides disposed for axially balanced cam action on said cam track relative to,

contact therewith by said bearing means for said rod, chamber means which includes surface of said piston and inner wall surface of said cylinder and the capacity of which is variable upon reciprocation of said piston, an inlet for said chamber means, an outlet'for said chamber means, inlet valve means for controlling said inlet, and outlet valve means for controlling said outlet, said inlet and outlet and said inlet'valve means and said'outlet valvemeans being arranged to successively direct ingress of gaseous material into said chamber means and egress of gaseous material from said chamber means during the intake and exhaust strokes respectively of said piston in said cylinder.

3. In a compressor-motor of the character described, the combination comprising a rod, bearing means affording longitudinal and rotational movement of said rod in a fixed axial position,

an undulatory cam ring secured to said rod in coaxial relation with the axis of said rod and v presenting complementarycam tracks on each side of said cam ring, a plurality of pairs of cam rollers which are fixedly positioned with one cam roller of each pair of cam rollers opposed to the other roller of the pair for contact with the complementary cam tracks presented by said cam ring and which are disposed for axially balanced action on said cam ring during reciprocation and rotation of said cam ring and rod, a rotatably mounted power shaft in axial alignment with saidrod, power transfer means between said shaft and said rod adapted to afford simultaneously continuous rotary motion of said shaft and continuous rotary motion of said rod during the reciprocation of said rod, a peripherally cylindrical piston fixed to said rod in coaxial relation thereto and spaced from said cam ring with a bearing member of saidbearin'g means therebetween, a cylinder surrounding said piston and coaxial therewith arranged for reciprocation of said piston therein, chamber means which includes surface of said piston and inner wall surface of said cylinder and the capacity of which is variable upon reciprocation of said piston, an

inlet for said chamber means, an outlet forsaid chamber means, inlet valve means for controlling said inlet, and outlet valve means for controlling said outlet, said inlet and outlet and said inlet valve means and said outlet valve means being arranged to successively direct ingress of gaseous material into said chamber means and egress of gaseous material from said chamber means during the'intake and discharge strokes respectively of said piston in said'cylinder.

4. In a compressor-motor of the character described, the combination comprising a rotatably mounted rod, cam means interposed between said rod and a fixed member for -reciprocating said rod upon continuous rotation of said rod, said cam means comprising a continuousundulato'ry cam track and a plurality of cam guides disposed for axially. balanced cam action on said cam track relative to the axis of said rod, a peripherally cylindrical piston coaxially fixed to said rod, a cylinder surrounding said piston in coaxial relation therewith and arranged for reciprocation of said piston therein, a cylinder head for said piston, a pair of diametrically opposed inlet ports in the wall of said cylinder, a. pair of diametrically opposed outlet ports in the wall of said cylinder angularly disposed relative to said inlet ports, and a pair of diametrically opposed valve ports in the side wall 01' said piston, said inlet ports and said outlet ports and said valve ports being arranged for successive traversing of said inlet ports and said outlet ports by said valve ports upon the intake and discharge strokes respectively of said piston.

5. In a compressor-motor of the character described, the combination comprising a rod, fixed bearing means arranged to fixedly maintain the axial alignment of said rod and to afford longitudinal and rotational movement of said rod, a

cam member secured to said rod and presenting undulatory annular cam track means coaxial with the axis of said rod, fixed cam guide means arranged for coaction with said cam track means to effect reciprocation of said cam member and said rod upon rotation of said rod, a rotatable power shaft in axial alignment with said rod, means for rotating said power shaft, an axially slidable connection between said power shaft and said rod adapted to rotate said rod upon rotation of said power shaft, common housing means for said cam member, for said cam guide means, and for said axially slidable connection, a peripherally cylindrical piston fixed to said rod in coaxial relation thereto and outside of said housing means and spaced from said cam member. with-a bearing member of said bearing means that-is integral with said housing means therebetween, a cylinder surrounding said piston and coaxial therewith and arranged for reciprocation of said piston therein, the peripheral wall of said piston being in close proximity to the inner wall of said cylinder and maintained out of pressure-contact therewith by said bearing means for said rod, chamber means which includes surface of said piston and inner wall surface of said cylinder and the capacity of which is variable upon reciprocation of said piston, an inlet for said chamber means, an outlet for said chamber means, inlet valve means for controlling said inlet, and outlet valve meansfor controlling said outlet, said inlet and outlet and said inlet valve means and said outlet valve means being arranged to successively direct ingress of gaseous material into said chamber means and egress of gaseous material from said chamber means during the intake and discharge strokes respectively of said piston in said cylinder. 1 l

6. In a compressor-motor of the character described, the combination comprising a rod, fixed bearing means arranged to fixedly maintain the axial alignment of said rod and to afford longitudinal and rotational movement of said rod, a

rotatably mounted power shaft in axial alignment with said rod, a telescopically slidable connection between said power shaft and said rod for transfer of rotational power, a, cam member fixed to said rod presenting continuous undulatory cam track means, a plurality of fixed cam guide means disposed for coaction with said cam track means to reciprocate said rod upon rotation of said rod and arranged for axially balanced action on said cam track means relative to the axis of said rod, a piston fixed to said rod and spaced from said cam member with a bearing of said bearing means therebetween, said piston being provided with a peripherally cylindrical open ended skirt coaxial with the axis of said rod, 9. cylinder surrounding said piston skirt and arranged for reciprocationof said piston therein, a cylinder head for said cylinder provided with a, reentrant m'ember adapted'to fit within the open ended skirt of said piston, a pair-of diametrically opposed inlet ports in the side wall of said cylinder, a pair of diametrically opposed outlet ports in the side wall of said cylinder, and a pair of diametrically opposed valve ports in the skirt of said piston, said inlet and outlet ports and said valve ports being arranged for successive traversing of said inlet ports and said outlet ports by said valve ports upon reciprocatory androtational movement of said piston as controlled by said cammember.

7. In apparatus of the character described, the combination according to claim 6 wherein the skirt of said piston is maintained by-said bearing means out of pressure-contact with the wall -of said cylinder and which includes means between said cam member and saidv piston for preventing passage of lubricant toward said-piston from said cam member.

' 8. In a compressor-motor of the character described, the combination comprising a rod, 2. motor-generator having a rotatable power shaft, power transfer means between said power shaft and said rod adapted to effect simultaneously continuous rotation of said power shaft and reciprocating'an'd continuous rotation of said rod,.

chamber, bearing means between said piston and, said power transfer means aflording reciprocaii,

tory and rotational movement of said rod, and an 1 essentially gas-proof casing about said motor-v generator and about said power transfer means and arranged to build up pressure of gaseous material within said casing upon seepage of gaseous material from the region of said compression-expansion chamber past said bearing ,member toward said power-transfer means.

9. In a compressor-motor of the character described, the combination comprising; a rod, fixed bearing means arranged to fixedly maintain the axial alignment of said rod and to afford longitudinal and rotational movement of said rod, a cam member secured to said rod and presenting undulatory camtrack mean coaxialwith the axis said rod adapted to rotate said rod upon rotation v of said power shaft, a peripherally cylindrical: piston-coaxially fixed to said'rod in spaced relation to. said cam member with a bearing member of said bearing means therebetween, a cylinder surrounding said piston and coaxial therewith and arranged for reciprocation of-said piston. therein,-. the peripheral wall of said piston being" in close proximity to the inner wall of said cylinder and maintained out of pressure-contact therewith by said bearing means for said rod, chamber means which includes surface of said piston and inner wall surface of said cylinder and the capacity of which is variable upon reciprocation of said piston, an inlet for said chamber means, an outlet for said chamber means, inlet valve means for controlling said inlet, and outlet valve means for controlling said outlet, said inlet and outlet and said inlet valve means and said outlet valve means being arranged to successively direct ingress of gaseous material into said chamber means and egress of gaseous material from said chamber means during the intake and discharge strokes respectively of said piston in said cylinder and said compressor-motor apparatus comprising an essentially gas-proof casing which is disposed about said cam-member, said cam guide means, said electrical motor-generator and said axially slidable connection and which is arranged to buildup pressure within said casing uponseepage of gaseous material past said hearing member in the direction from said piston toward, said cam-member.

10. Infa compressor-motor of the character described, the combination comprising a rod, a peripherally cylindrical piston fixed to said rod in coaxial relation thereto, reciprocating means spaced from said piston for axially reciprocating said rod during rotation of said rod, spaced bearings between said piston and said reciprocating means adapted to fixedly maintain. the axial alignment of said rod and to afford longitudinal and rotational movement of said rod, trap means between said spaced bearings adapted to retain any lubricant passing the bearing of said spaced bearings that is more adjacent said reciprocating means before it reaches the bearing of said spaced bearings that is more adjacent variable upon reciprocationof said piston, an

inlet for said chamber means, an outlet for said chamber means, inlet valve means for controlling said inlet, and outlet valve means for controlling said outlet, said inlet and outlet and said inlet valve means and said outlet valve means being arranged to successively direct ingress of gaseous material into said chamber means and egress of gaseous material from said chamber means during the intake and discharge strokes respectively of said piston in said cylinder.

ment of said rod and to afford longitudinal and rotational movement of said rod, a housing surrounding said reciprocating means, a support member which projects away from said piston inwardly into said housing a substantial distance and in which said bearing member is secured, a cylinder surrounding said piston and coaxial therewith and arranged for reciprocation of said piston therein, the peripheral wall of said piston being in close proximity to the inner wall of said cylinder and maintained out of pressure-contact therewith by said bearing means for said rod,

of said cylinder are of substantially lesser angular extent about the axis of said rod than said inlet ports.

16. In a compressor-motor of the character described, the combination according to claim 14 wherein said inlet and outlet ports in the wall of said cylinder are simple openings and wherein the valve ports in the side wall of said piston likewise are simple openings.

17. In a compressor-motor of the character described, the combination comprising a rotatably mounted rod, a peripherally cylindrical piston affixed coaxially to said rod; means for reciprocating said rod upon continuous rotation of said rod, a cylinder surrounding said piston and arranged for reciprocation of said piston therein, a cylinder head for said cylinder on each end of said piston, a first pair of diametrically opposed valve ports in the side wall of said piston communicating with one end of said piston, a second pair of diametrically opposed valve ports in the chamber means which includes surface of said piston and inner wall surface of said cylinder and the capacity of which is variable upon reciprocation of said piston, an inlet' for said chamber means, an outlet for said chamber means, inlet valve means for controlling said inlet, and outlet valve means for controlling said outlet, said inlet and outlet and said inlet valve means and said outlet valve means being arranged to successively direct ingress of gaseous material into said chamber means and egress of gaseous material from said chamber means during the intake and discharge strokes respectively of said piston in said cylinder.

13. In a compressor-motor of the character described, the combination according to claim 12 which comprises trap means between said bearing member and said piston, and a second hear-- ing member between said trap means and said piston, said second bearing member being carried by a support which projects away from said piston inwardly into said trap means a substantial distance.

14. In a compressor-motor of the character described, the combination comprising a rotatably mounted rod, a peripherally cylindrical piston fixed coaxially to said rod, means for reciprocating said rod upon rotation of said rod, a cylinder surrounding said piston and arranged for-reciprocation of said piston therein, a cylinder head for said cylinder, a pair of diametrically opposed inlet ports in the wall of said cylinder, a pair of diametrically opposed outlet ports in the wall of said cylinder angularly disposed with respect to said inlet ports, and a pair of diametrically opposed valve ports in the peripherally cylindrical side wall of said piston, said inlet and outlet ports in the wall of said cylinder and said valve ports in the side wall of said piston being arranged for successive traversing of said inlet ports and said outlet ports by said valve ports upon intake and discharge strokes respectively or said piston, and said inlet ports being of substantially greater angular extent about the axis of said rod than said valve ports in the side wall of said piston.

15. In compressor-motor apparatus of the character described, the combination according to claim 14 wherein said outlet ports in the Wall side wall of said piston disposed angularly with respect to said first pair of valve ports and communicating with the other end of said piston, a pair of diametrically opposed inlet ports in the wall of said cylinder, a pair of diametrically opposed outlet ports in the wall of said cylinder, said inlet and outlet ports being common to said first and second valve ports and being arranged to be successively and alternately traversed by said first and second pairs of valve ports upon reciprocation and continuous rotation of said piston.

18. In a compressor-motor of the character described, the combination comprising a rod, a piston fixed to said rod, said piston comprising a pair .of peripherally cylindrical, oppositely extending open ended skirts coaxial with the axis of said rod with a separator wall therebetween, means for controlling simultaneous reciprocatory and rotary movement to said rod and said piston axially of said rod, a cylinder surrounding said skirts and coaxial therewith and arranged for reciprocation of said piston therein, a reentrant cylinder head for each of said piston skirts and arranged to fit therein, a first pair of diametrically opposed valve ports extending directly through one of said piston skirts, a second pair of diametrically opposed valve ports extending directly through the other skirt of said piston and angularly disposed with respect to said first valve ports, a pair of diametrically opposed intake ports extending directly through the wall of said cylinder, a, pair of diametrically opposed outlet ports extending directlythrough the wall of said cylinder, said inlet and outlet ports being common to said first and second valve ports and being arranged to be successively and alternately traversed by said first and second pairs of port valves upon the intake and discharge strokes of said piston skirts on each side of said barrier.

19. In a compressor-motor of the character described, the combination according to claim 18 ,wherein said barrier between said oppositely extending piston skirts is provided with a hub of substantially greater extent along the axis of said rod than the thickness of said barrier, said hub surrounding and being rigidly secured to said rod.

20. In a compressor-motor of the character described, the combination comprising a rotatably mounted rod, 2. peripherally cylindrical piston aflixed to said rod, means for reciprocating said rod upon continuous rotation of said rod, a cylinder surrounding said piston and arranged for reciprocation of said piston therein, a cylinder head for said cylinder on each end 01' said piston 01' said piston opening directly into the chamber on one side of said piston, a second valve port in the end wall of said piston angularly disposed with respect to said first valve port and opening directly into the chamber on the other end of said piston, an inlet port in the side wall of said cylinder, and an outlet port in the side wall of said cylinder angularly disposed with respect to said inlet port, said inlet and outlet ports being common to said first and second valve ports and arranged to be successively and alternately upon reciprocation and continuous rotation of said piston.

21. In a compressor-motor of the character described, the combination comprising a rotatably mounted rod, cam means for reciprocating said rod upon rotation of said rod, a peripherally cylindrical piston coaxially fixed to-said rod, a cylinder surrounding said piston and arranged for reciprocation or said piston therein, a cylinder head (or said cylinder, an inlet port and an outlet port in the wall of said cylinder, a port valve in the side wall of said piston, said inlet and outlet ports in said cylinder and said port valve in the side wall of said piston being arranged for successive traversing of said inlet and outlet ports by said valve port upon intake and discharge strokes respectively ofsaid piston, and means for changing therelative angularposition about the axis of said rod between said cylinder and said cam means so as to reverse the action of said compressor-motor.

22. In a compressor-motor of the character d scribed, the combination comprising a rotatably mounted rod, cam means for imparting axially reciprocatory movement to said rod upon rotation of said rod, a piston fixed .to said rod, said piston including a peripherally cylindrical openended skirt coaxial with the axis of said rod, a cylinder surrounding said skirt and coaxial there. with and arranged for reciprocation of said piston therein, cylinder head means for said cylinder, inlet and outlet ports in said cylinder, port valve means in said skirt of said piston, said inlet and outlet ports in said cylinder and said port valve means in said skirt being arranged for successive traversing of said inlet and outlet ports by said valve ports upon intake and discharge strokes respectively of said piston, and means for changing the angular position of said cylinder relative to the axis or said rod so as to reverse the action of said compressor-motor.

23. In a compressor-motor'oi the character described, the combination comprising a rotatably mounted rod, means for imparting axially reciprocatory movement to said rod simultaneously with rotation of said rod, a first peripherally cylindrical piston fixed to said rod in coaxial relation therewith, first chamber means including a first fixed cylinder for reciprocation of said first piston therein and including inlet and outletv ports and valve means for controlling said ports and arranged for successive introduction oi! gaseous material into said chamber means during the intake stroke of said first piston and for expulsion of gaseous material from said chamber means during the discharge stroke of said first piston, a second peripherally cylindrical piston fixed to said rod in coaxial relation to said rod traversed by said first and second valve ports and in spaced relation to said first piston, second chamber means including a second cylinder for reciprocation of said second piston therein and including inlet and outlet ports and valve means for controlling said ports and arranged for successive introduction oi gaseous material into said second chamber means during the intake stroke of said second piston and for expulsionof gaseous material from said chamber means during the discharge stroke oi said second piston,

and means for directing gaseous material from the discharge port of said second chamber means to the intake port of said first chamber means.

24. In a compressor-motor or the character described, the combination comprising a first rod, means 'for fixedly maintaining the axial align merit of said rod, a second rod, means for fixedly maintaining the axial alignment of said second rod in axial alignment with said first rod, means between the opposed ends of said first and second rods for effecting rotation of said rods at the same speed of rotation, means for axially reciprocating said first rod uponrotation 01' said first rod, means for axially reciprocating said second rod upon rotation of'said second'rod in complernentary and opposite relation to the reciprocation of said first rod, a first peripherally cylindrical piston fixed to said first rod in axial relation thereto, first chamber means including a fixed cylinder for reciprocation of said first piston therein including inlet and outlet ports and'valve means for controlling said ports and arranged for successive introduction and expulsicgr of gaseous material into and from said first chamber means during the intake and discharge strokes respectively of said first piston, second chamber means.

including a fixed cylinder for reciprocationpt said second piston therein including inlet and outlet ports and valve means for controlling said ports and arranged for successive introduction and expulsion of gaseous material into and from said second chamber means during the intakeaxially reciprocating said rod upon continuous rotation of said rod, said cam means comprising continuous undulatory cam track means and cam guide means for cooperation with said continuous undulatory cam track means, a rotatably mounted power shaft in axial alignment with said rod, .an axially slidable connection between said power shaft and said rod adapted to rotate said rod upon rotation of said power shaft, a peripherally cylindrical piston affixed to said rod in coaxial relation thereto and spaced from said cam means with a bearing comprised by said bearing means therebetween, a cylinder surrounding said piston and arranged for reciprocation of said piston therein, the peripheral surface of said piston being maintained out of pressure-contact with the inner wall of said cylinder, a cylinder head for said cylinder, inlet and outlet port-s in the side wall of said" cylinder, and valve port means in the side wall of said piston, said inlet and outlet ports and said valve port means being arranged for controlling ingress and expulsion of gaseous ma.-

terial from said cylinder upon the rotation'and