US2145575A

US2145575A - Reversing valve mechanism

Info

Publication number: US2145575A
Application number: US745123A
Authority: US
Inventors: Joseph R Zwickl
Original assignee: BALDWIN SOUTHWARK CORP
Current assignee: BALDWIN SOUTHWARK CORP; BALDWIN-SOUTHWARK Corp
Priority date: 1934-09-22
Filing date: 1934-09-22
Publication date: 1939-01-31
Anticipated expiration: 1956-01-31

Description

Jan. 31, 1939. J. R. ZWICKL REVERSING VALVE MECHANISM Filed Sept. 22, 1934 5 Sheets-Sheet 1 JN VENTOR J/QZW/tk/ Jan.31,1939. R W.CKL 5 2,145,575

REVERSING VALVE MECHANISM Filed Sept. 22, 1934 '5 Sheets-Sheet .2

' INVENTOR c/ 4 W/Ck/ Jan. 31, 1939. J. R. ZWICKL. 7 2,145,575

REVERSING VALVE MECHANISM Filed Sept. 22, 1934 v s Sheets- Sheet 4 INVENTOR Fatentecl Jan. 31, 1939 UNITED STATES PATENT OFFICE Baldwin-Southwark Corporation, a corporation of Delaware A Application September 22, 1934, Serial No. 745,123

9 Claims.

This invention relates generally to air conditioning apparatus employing a refrigerating system adapted to be used for either heating orcooling and more particularly to an improved valve mechanism for interchanging the functions of a condenser and evaporator whereby the refrigerating system may be employed to heat or cool the air of rooms, railroad cars or other enclosures.

It is well-known that a refrigerating system employing a condenser and evaporator may be used for either heating or cooling purposes merely by causing the conditioned medium to be circulated over the evaporator to be cooled thereby or to be circulated over the condenser to be heated thereby. Normally a condenser and evaporator, and a compressor in cases of a compression system, have a fixed physical relation to each other, and in the most desirable form of heater-cooler air conditioning apparatus, room air is passed over one of the heat exchange elements and outside air over the other, although it will of course be understood that liquid medium may be employed in place of the room air if it is desired to indulge in the expense of the necessary liquid piping and radiating surface for the room. In view of the fixed physical relation of the refrigerating elements, it is necessary, in order to interchange or reverse the functions of the condenser and evaporator, to reverse the condenser and evaporator connections with respect to the suction and discharge of the compressor. This reversal is usually effected by valve mechanisms of various types, but a great deal of difiiculty has been experienced in providing valves for this purpose which would be absolutely leakproof.

It is one object of my invention to provide an improved valve mechanism for interchanging the functions of the condenser and evaporator. A further and more specific object of the invention is to provide an improved poppet type valve mechanism so constructed and arranged in combination with yleldable sealing rings so as to provide a very effective leakproof construction.

A further object is to provide an improved poppet type valve mechanism employing in an improved manner a sylphon bellows as the sealing element. A further object in this respect is to provide an improved valve mechanism so constructed and arranged in combination with bellows sealing means that the bellows is subjected to minimum pressure at all times and more specifically to the suction pressure of the system.

Another object is to provide an improved reversing valve mechanism of the multiple poppet Valve type arranged in an improved manner that the valves move in opposite directions during the revers ng operation. Another object is to provide improved actuating means for the valve mechanism whereby the valves may be positively and properly seated with minimum eflort.

A further object is to provide a valve casing, a valve seat member, and a valve stem guide all of which are so constructed and arranged that the valve mechanism may be manufactured economically and have a. high degree of durability and effectiveness in permitting the relatively movable, parts to be maintained in proper relation and yet efilciently perform the reversing function.

Other objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawings in which:

Fig. 1 is a diagrammatic view of a compressor, condenser and a refrigerating system embodying one form of my improved valve mechanism;

Fig. 2 is an enlarged sectional view of one form of my improved valve mechanism;

Fig. 3 is a side elevation of a valve mechanism showing partially in section the valve operating mechansm;

Fig. 4 is a sectional view taken on the line t-t f Fig. 3; i

Fig. 5 is a modified form of my improved valve mechanism whereby one set of valve seats is screwed in position on the under side of the valve casing, the sealing bellows however remaining under low pressure at all times;

Fig. 6 is a further'modificatlon wherein low pressure bellows are employed in combination with an opposed type of valve mechansm:

Fig. 7 is a further modified form ofvalve mechanism whereby both poppet valves simultaneously move either up or down to eilect reversal, although the sealing bellows in this form is ultimately subjected to high and low pressure.

In the illustrated embodiments of the invention which are shown herein merely for the purpose of disclosing certain specific forms among possible others that the invention might take, I- have diagrammatically incorporated the invention in a compression refrigerating system having a suitable motor driven compressor dlagram-. matically indicated at l and a pair of complementary heat exchange elements 2 and 8 which are interconnected by any suitable expansion valve mechanismgenerally indicated at 4 whereby refrigerant may be expanded in either direction of flow @through the heat exchange elements 2 and 3. Compressor cylinders 3, or equivalent compressing mechanism, are connected to a common high pressure or discharge pipe 6 which communicates with my improved reversing valve mechanism generally indicated at I. The heat exchange elements 2 and 3 are respectively connected to the valve mechanism I by pipes 3 and 9, while the suction or low-side of the compressor is connected by a pipe It with the valve mecha nism. The direction of fluid flow through the high side toward the valve mechanism is the same at all times and likewise the direction of fluid flow in the low side away from the valve mechanism is also in that direction at all times. Thus these passages may be hereinafter referred to as the uni-directional flow high and low passages or as the compressor'and high and low passages. Such terms will of course include any continuations of said passages as hereinafter described.

As shown in Fig. 2, the reversing valve mechanism comprises a valve body 12 formed preferably of a rectangular flat block of steel or other suitable metal and having a thickness just sufllcient to accommodate the maximum diameter of one of the operating valve mechanisms. The valve block encloses a pair of double seating poppet type valves generally indicated at l3 and I4. Inasmuch as the structure for each valve is identical, it will suffice to describe only the valve mechanism [3, although where itis necessary to refer to parts of the valve mechanism 14, such parts will be given the same numbers of corresponding parts of valve l3, but primed. The valve body is provided with a series of successively enlarged bores l5, l6 and I1 communicating at their lower end with a horizontal high pressure inlet passage l8 while a continuation IQ of this passage also communicates with the second valve mechanism l4. Suitable threaded plugs close the lower end of the bore l5. Passages l5, l6 and the interior of sleeve 24 (and the corresponding passages of valve l4) constitute what may be herein referred to as reversing or cross-over passages.

The valve I3 is of the double poppet type preferably having differential tapered valve heads 2| and 22, while a suitably fluted guide stem 23 projects downwardly from the valve and is guided in bore 15. A lower tapered valve seat is provided at the corner of bore 15 while an upper tapered valve seat is provided on the corner of a hollow valve seat member 24. This member has a peripheral flange portion 25 received in bore I! while suitable packing is interposed at 23 between flange 25 and the shoulder of bore IT. A portion of the valve member 24 also projects down into bore IS. The valve seat member preferably has a snug flt with bores l6 and IT to insure the utmost accuracy in alignment of the valve and seats. To eliminate further any possibility of misalignment of the valves and seats the valve seat member 24 does not have any threaded engagement with the valve block i2 so that there is no opportunity to distort the valve seat member when placed in position as there would be if this member were screwed into position. To hold the member in position while at the same time providing a suitable housing for a sealing bellows, I have provided a cylindrical housing 23 whose lower end has threaded engagement with the upper end of bore I I and is adapted to press the valve seat member in position by engaging a shoulder 23 thereof. The housing "also telescopes with the upper portion of the valve seat member to maintain a cooperating aligning relation. This upper portion 30 has a transverse portion to assist if desired in guiding the valve stem 3|, while ports 30a permit equalization of pressure on each side of the transverse portion. The upper end of the valve stem has an extension 32 threadedly secured thereto.

To seal the valve mechanism against leakage along the stem, I have provided an annularly corrugated metallic bellows or diaphragm 33 whose lower flange 34 is soldered or otherwisehermetically secured to the element 32 preferably at the lowermost surface thereof. The uppermost flange 35 of the bellows is similarly secured to a sleeve 36 seated in a suitable recess 31in the housing 23. Sleeve 36 is held in position by a collar 38 having threaded engagement with the exterior of housing 28. The collar, sleeve and housing are hermetically sealed by introducing solder or other suitable material through suitable openings 39 to an annular recess 40 commonly overlying the housing and sleeve 36.- The sleeve 36 is thereby rigidly held in fixed relation to the housing 28, and hence is adapted to serve as a suitable guide for the extension valve stem 32.

An advantage of the combination of extension 32, bellows 33 and sleeve 36 is that these elements may be secured together as a sub-assembly unit and then threadedly secured to the valve stem 3|, thus permitting the bellows to be soldered without any possibility of distorting the valve seat member by transmission of the soldering heat thereto.

The bores l6 and 16' function as valve chambers communicating with pipes 8 and 9, of the heat exchange elements, as through suitable lateral ports or passages diagrammatically indicated in Fig. 2 by dotted circles 42 and 42' and shown more clearly in Fig. l. These may be hereinafter referred to as the reversible flow passages, or the heat exchange element passages.

In assembling the valve mechanism, valve 23 is first inserted in chamber l6 and then a spring 45 is placed over valve stem 3 I, after which valve seat member 24'is placed in position in bores i3 and 11 with suitable packing 26 at the shoulder 25. Housing 28 is then screwed into position to clamppacking 26. The

bellows unit

32, 33 and 36 is inserted within the housing and stem 32 screwed into threaded engagement with stem 3|, the sleeve 33 resting in the annular recess 31 at the upper end of the housing. Collar 38 is then screwed tightly into position to hold the sleeve 36 firmly to its seat after which the joint formed by recess 31 and sleeve 38 is hermetically sealed by solder or other suitable sealing material in annular recess 40. The annular Joint at 41 is also soldered.

In operation of the valve mechanism per se,

position and valve I4 in its lower closed position as shown in Fig. :2. Referring now to Fig. 1,.itis

it is assumed that valve 13 is in its upper closed seen that fluid pressure will be discharged from cylinders 5 through pipe 8 to (Fig.2) passages l8 and I3 and thence upwardly through bore 15 to valve chamber i6 and through port 42 :and pipe 8 to heat exchange element '2 now functioning as a condenser. Any suitable cooling medium such as air or water may be employed to cool the condenser, the condenser refrigerant flowing through the expansion means -4to the heat exchange element 3 now functioning as an evaporator. The evaporated refrigerant flows through pipe 9 and port 42, thence upwardly from chamber l6 past valve head 2| and out through passages 48 and 49 (and ports in valve seat members 30 and 3!! registering with passages 48 and 49) to the suction pipe Ill leading to the compressor intake.

It will be noted that during the foregoing operation the upper side of both valves is subjected to the relatively low suction pressure, and hence the bellows 33 and 33' are also each subjected to this low pressure.

To interchange the functions of the heat exchange elements 2 and 8, which is accomplished by reversing the direction of refrigerant flow therethrough, it is only necessary to move valve l3 to its lower closed position and move valve H to its upper' closed position in which event fluid is discharged from cylinders 5 through pipe 8 to passages l8 and IS, the high pressure gas in this case flowing upwardly through bore It into chamber l6 and thence outwardly through port 42 to pipe 9 and heat exchange element 3 now functioning as the condenser. Any suitable medium such as air or water may be employed to cool the condenser 3. The condensed refrigerant liquid then fiows through any suitable expansion mechanism 4 to heat exchange element 2 now functioning as an evaporator from which the evaporated gas under relatively low suction pressure flows through pipe 8 and port 42 to valve chamber l6 and thence upwardly past valve head 2| to passage 49 and pipe Ill to the suction side of the compressor.

It will again be noted from the immediately foregoing operation that the upper side of both valves is subjected to the low suction pressure and likewise the bellows 33 and 33' are also subjected to this same low pressure. Hence it is seen that in either position of the valve mechanism, and at all times while in use, the sealing means such as the bellows, soldering joints and the like, are subjected only to relatively low suction pressure thereby minimizing the possibility of leakage and deterioration or fatigue of the bellows as would otherwise occur in case the bellows and joints are subjected at any time to the high discharge pressure. l.

The springs 65 and 45' may or may not be used depending upon the particular pressure condiiions under which the valve mechanism is used and also depending upon the tightness with which it is desired to seat the valves or to control the ease of operation thereof as will be more fully set forth hereinafter. The springs operate on the valves against the high discharge pressure which is always present on the under side of each valve. The flexibility of the bellows 33 and 33' will not impose any appreciable resistance to axial movement of the valves.

Valve actuating mechanism.--While various arrangements may be provided for moving the valves in opposite directions, yet I have provided as shown in Figs. 3 and 4 a relatively simple and yet very effective mechanism for insuring positive seating '01 each valve whereby upon seating of one valve, :1. fixed fulcrum is provided about which the operating lever may pivot to seat the other valve or vice versa, together with floating means for insuring that the valves will tend to be simultaneously initially unseated during a reversing operation and for preventing disalignment of the valve stems during pivotal movement of the operating lever.

The floating means just above referred to consists in. having the upper end of the valve stem extension 32 pivotally connected as at 50 to a. floating operating lever 5| while the other valve stem 32' is connected to said lever through a pin and slot connection 52. A floating fulcrum block 53 is pivotally connected as at H to the operating link 8! at a point intermediate the valve stems and, in the position as shown, this block is slightly spaced from the upper surfaces of collars 38 and 38'. The outer end of lever 5i is pivotally connected as at 65 to a vertical link 56 whose lower end is pivotally connected at 5'! to a lever link lit. One end of this link has a fixed pivotal support 59 while the other end is connected to a nut Gil as by a pin and slot connection 6!. This nut is normally non-rotatable but is axially movable along a screw 62 which is suitably journalled at its upper and lower ends in a housing 63. This housing may be supported in any suitable manner in fixed relation to the valve body l2. Screw 62 may be rotated in any desirable manner such as through bevel gears 62a and a shaft 64 like-' wise suitably Journalled in housing 63 A hand crank, motor or other suitable actuating means may be removably or permanently secured to shaft 68 for actuation thereof.

Operation of valve and its actuating mechanism-Discharge pressure acts on one side of the valves and suction pressure on the other side thereof, so consequently if the valves are seated on either one of the two sets of seatsjany unbalancing force acting on either valve'is the effective area of the valve multiplied by the pressure difference. If the valve is seated toward the suction side. then the higher pressure on the discharge side will keep the valve closed whereas if the valve is seated toward the discharge side, the discharge pressure tends to open the valve and the same therefore, the effective valve area toward the suction side is made larger than the area toward the discharge side, then the force which tries to open the valve when it is seated toward the discharge side will be less than the force which keeps the valve closed when it is seated toward the suction side. By applying to the valve stem a spring 45 of such proportions that the spring force is larger than the differential pressure force acting on the valve in an opening direction when the valve is seated toward the discharge side, but is smaller than the force which keeps the valve closed when it is seated toward the suction side, then this valve will stay closed when seated toward either the suction or discharge side. If the valve is seated toward the discharge side, the spring keeps the valve closed against the pressure difference. and if the valve is seated toward the suction side. then the pressure difference closes the valve against the spring force.

The foregoing relation between the suction and discharge pressures. the spring force and valve areas are expressed mathematically as follows: If F1 designates the effective area on the smaller side of the valve, F2 the eflfective area on the larger s de of the valve. D, the pressure difference. and S the spring force. then the relation which ho ds. is F1 multiplied by D1: is smaller than S. and this again is smaller than F2 multiplied by D1), 01 stated otherwise F1 XD1n S F?YD;o.

Now assuming the valves l3 and M to be in the position shown in Fig. 2 and that it is desired to reverse their relation, sha t 64 is rotated to there- I by rotate screw 62 and raise nut 60' together with lever 58, link 56 and lever 51, Figs. 2 and 3. As a result, lever 5| will swing in a counterclockwise direction about pivot 50, thereby raising valve l4 whereupon spring 45 will move valve I3 downwardly. However, .the extent of downward movement of valve I3 is instantly limited by the fact that stem 32 in moving downwardly will also move lever 5| downwardly until floating block 53 engages the top of valve collars 38 and 38.". Only a small clearance is normally provided between block 53 and said collars so that only a very small degree of initial opening movement of the valve will take place before block 53 comes into action and rests on top of collars 38. Spring 45 will constantly urge valve I3 downwardly so that block 53 will engage collars 30 and thus prevent downward movement of valve I3 until lever 5| has moved upwardly in a counterclockwise direction. Such movement of lever 5| will insure that valve I4 will raise as valve I3 lowers until the two valves seat simultaneously or substantially so against the new set of seats, whereupon the refrigerant flowthrough the passages will be reversed. It is thus seen that block 53 in resting on collars 38 insures that one valve cannot move out of step with the other valve.

On the other hand, assuming the valves to be in their reversed position as just above described and that it is now desired to shift them back again to the position shown in Fig. 2, screw 62 will be reversely rotated so asto swing lever 5| in clockwise direction, whereupon one valve or the other will initially open to allow equalization of pressure on the high and low sides. Thereupon any tendency of spring 45' to move valve I4 downwardly more rapidly than. valve I3 moves upwardly willbe restrained by operation of floating block 53 engaging the top of collars 38 in the manner above described.

It will of course be understood that if additional seating pressure is desired on the valves, it is only necessary to rotate screws 62 and cause lever 5| to fulcrum about the

pivots

50 and 52 of the valve stems in exerting more pressure on the valves. Also it is apparent that springs 45 and 45 may be omitted if it is desired to rely entirely upon seating and unseating pressures being applied solely through the screw and leverage system disclosed, although the springs are desirable under many circumstances as previously set forth.

Modification in Fig. 5.-In Fig. 5 a valve body I has a low pressure or suction side II and a high pressure or discharge side 12. Valve chambers I3 and I4 are provided with valve seats I and 16 whereby valves I1 and I8 are adapted to seat toward the low pressure side. Valve seats I9 and 80 are provided toward the high pressure or discharge side I2 through the provision of sleeves 8| and 82 having threaded engagement with suitable bores 84 and 85. The valves have suitable fluted guides such as 80 slidably received in valve seat sleeves 8| and 82 while valve stems such as 81 extend upwardly through. guides 88 which project upwardly from the valve body I0 in axial alignment with each of the valves" and I8. A collar 89 is hermetically .secured to valve stem 81 while a bellows 00 is suitably secured and sealed to collars 89 and 9|, the latter having threaded engagement with the lower end of guide 88. C01- lar 9| is hermetically sealed at 82 with the valve body I0 as by solder, welding or the like. Suitable pivot elements such as 93 are secured to theupper ends of the valve stems. It will be understood that the bellows and sealing arrangement are identical for the two valves and hence only one has been described.

The passage arrangement employed in this construction permits all vertical passages to be drilled may be employed with this arrangement also,

although it will be noted that no springs are employed in Fig. 5, therebynecessitating the valve actuating means including lever 5| to exert full opening and closing forces.

Modification of Fig. 6 .In this modification the low pressure or suction side 100 communicates with chambers I0 I and I02 disposed on the inside of valves I03 and I04. The high pressure or discharge side I05 of the refrigerating system communicates with chambers I06and I0'I disposed on the outside of the valves. One of the heat exchange elements is connected by a pipe I08 to a valve chamber I09 while the other heat exchange element isconnected by a pipe |I0'-to a valve chamber I I I. A common valve stem I I2 connects the two valves I03 and I04, this stem passing through guides H3 and H4 which have threaded engagement with the valve bodies. Sylphon bellows H5 and H6 are secured to guides H3 and I I4 respectively and to suitable collars H8 and I I9 which in turn are fixed to the valve stem.' All of these various elements are hermetically sealed to prevent leakage, and it will be noted that any.

leakage to either of the bellows chambers will be, at all times, from the low pressure or suction passage I00, thereby insuring that the bellows will operate only under minimum pressure the same as in the preferred form.

Any suitable actuating means may be employed to shift valve stem II2. One suitable means for this purpose is'diagrammatically indicated as a lever I20 having a fixed pivot I2I and a suitable piri and slot connection I22 with stem I I2, whereupon the upper end I23 of lever I20 may be oscillated to shift the valves. The reversal of fluid flow through the various passages is the same as in the preferred form. v

Modification of Fig. 7.ln this arrangement the sealing bellows are alternatively subjected to high and low pressures. This valve arrangeent comprises a high pressure inlet I30 from t compressor and a low pressure outlet I3I communicating with the suction side of the compressor. The heat exchange elements communicate with their respective valves mechanisms through passages I32 and I33. The valves I34 and I35 are simultaneously either in their lower position as shown in Fig. 'l or in their upper position. With the valves seated in their lower posi-,

tion upon suitable sleeves I35 and I31, high pressure fluid flows from passage I30 past upper valve seat I38, thence through a cross passage I38 to a point beneath valve I34 so as to communicate with passage I33 which leads to a heat exchange element, now functioning as a condenser. The return low pressure fluid from the heat exchange element which is now serving as an evaporator is conducted through passage I32 to a diagonal passage I50, as from a point below valve I35, and

thence to a point above upper valve seat I30, the fluid then flowing downwardly past seat I39 to passage I3I which communicates with the suction side of the compressor.

When the functions of the heat exchange elements are interchanged, valves I35 and I36 are simultaneously moved to engage upper seats I30 ail-laws andfls, whereupon the high side I communicates with passage I32 (diagonaljpassage I38 being closed off by valve I34 in its upper position), while passage I33 now functioning as a return passage on the low pressure side communicates directly with passage I3I which leads to the suction side of the compressor (diagonal passage Il'l being closed 01! by valve I35 in im upper position).

The sealing arrangement for the valve stems I40 and I is the same as that shown in Fig. 5, and hence further detailed description is not essential here. However, the means for operat; ing the valve stems simultaneously in the same direction comprises as shown in Fig. 6 a shaft I42 rotatably journalled in the valve body I43 but held against axial movement. The upper end of shaft I42 is provided with screw threads engaging a nut I44 upon which is pivoted an equalizing cross arm I45 in turn pivotallyv secured to,

elements Mt (corresponding to elements 83 of Fig. 5). Upon rotation of shaft I42 through any suitable means, it is seen that nut I44 will cause arm I45 to raise or lower the valves simultaneously to effect the reversing'action previously described. While -this arrangement subjects the sealing bellows alternatively to high and low pressures, yet it has the advantage that at least one bellows is subjected to low pressure during part of the operation in addition to having the advantages of simplicity in the valve structure and the actuating mechanism for moving the valves.

From the foregoing disclosure of the several modifications, it is seen that I have provided a very desirable and yet relatively simple and compact mechanically sealed valve for reversing fluid and flow especially through a condenser and evaporator of a refrigerating cycle.

It will of course be understood that various changes in details of construction and arrangement of parts may be made'by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. A reversing valve mechanism in combination with a compressor-condenser-evaporator circuit comprising high and low pressure passages connected respectively to the compressor discharge and inlet and through which the fluid flows in only one direction, a plurality of reversing passages each communicating with said high and low pressure passages, reversible flow passages connected respectively to the condenser and evaporator and being in constant communication with said reversing passages, valve mechanisms for effecting communication between one of said reversible flow passages and only the low pressure passage and between. the other of said reversible flow passages and only the high pressure side or vice versa, said valve mechanisms and all of said passages being so arranged that each valve is always subjected on the same side to low pressure,, valve stems for actuating said valves on the low pressure side thereof, and means for hermetically sealing said stems and valves on said low pressure side whereby the hermetic seals are always subjected to low pressure.

2. A reversing valve mechanism in combination with a compressor-condenser-evaporator circuit comprising high and low pressure passages connected respectively to the compressor discharge and inlet and through which the fluid flows in only one direction, a pair of reversible flow passages connected respectively to the condenser and evaporator and through which the direction of fluid flow is to be alternatively reversed, a pair of reversing passages each of which is connected at one end to said low pressure passage and at their other end to said highpressure passage, each of said reversing passages having opposed valve seats disposed axially thereof and one set of seats being toward said high pressure passage and the other opposed set of seats being toward the low pressure passage, and double seating valves for said seats, said reversible flow passages communicating with said reversing passages at points intermediate said opposed valve seats,

' whereby when one of said valves is seated against the highpressure side and the other of said valves is seated against the'low pressure side then one of said reversible flow passages is connected with the low pressure passage and the other of said reversible flow passages is connected with the high pressure passage, or vice versa when said valves are reversely seated.

3. A reversing valve mechanism in combination with a compressor-condenser-evaporator circuit comprising high and low pressure passages connected respectively to the compressor discharge and inlet and through which the fluid flows in only one direction, a pair of reversible flow passages connected respectively to the condenser and evaporator and through which the direction of iiuid flow is to be alternatively reversed, a pair of reversing passages each of which is connected at one end to said low pressure passage and at their other end to said high pressure passage, each of said reversing passages having opposed valves seats disposed axially thereof and one set of seats being toward said high pressure passage and the other opposed set of seats being toward the low pressure passage, double seating valves for said seats, said reversible fiow passages communicating with said reversing passages at points intermediate of said opposed valve seats, whereby when one of said valves is seated against the high pressure side and the other of said valves is seated against the low pressure side then one of said reversible flow passages is connected with the low pressure passage and the other of said reversi= ble flow passages is connected with the high pressure passage, or vice versa when said valves are reversely seated, valve stems extending axially from said valves on the side seating towardsaid low pressure passage, and sealing means for said stems and valves whereby said sealing means is always subjected to low pressure in either direction of fluid flow through said reversible flow passages.

4. A reversing valve mechanism comprising high and low pressure passages through which the fluid flows in only one direction, a pair of reversible flow passages through which the direction of fluid flow is to be alternatively reversed, a pair of reversing passages each of which is connected at one end to said low pressure passage and at their other end to said high pressure passage, each of said reversing passages having opposed valve seats disposed axially thereof and one set of seats being toward said high pressure passage and the other opposed set of seats being toward the low pressure passage, double seating valves for said seats, said reversible flow passages communicating with said reversing passages 'at points intermediately of said opposed valve nected with the low pressure passage and the other of said reversible flow passages is connected with the high pressure passage, or vice versa when said valves are reversely seated, valve stems extending axially from said valves on the side seating toward said low pressure passage, and sealing means for said stems and valves whereby said sealing means is always subjected to low pressure in either direction of fluid flow through said reversible flow passages, said valves having difl'erential valve heads and opposed valve seats, the smaller valve head and seat being toward the high pressure passage and the larger valve head and seat being toward the low pressure passage.

5. A reversing valve mechanism comprising high and low pressure passages through which the fluid flows in only one direction, a pair of reversible flow passages through which the direcvalves for said seats, said reversible flow passages communicating with said reversing Passages at points intermediately of said opposed valve seats, whereby when one of said valves is seated against the high pressure side and the other of said valves is seated against the low pressure side then one of said reversible flow passages is connected with the low pressure passage and the other of said reversible flow passages is connected with the high pressure passage, or vice versa when said valves are reversely seated, valve stems extending axially from said valves on the side seating toward said low pressure passage, sealing means for said stems and valves whereby said sealing means is always subjected to low pressure in either direction 01' fluid flow through said reversible flow passages, said valves having dif- Ierential valve heads and opposed valve seats, the smaller valve head and seat being toward the high pressure passage and the larger valve head and seat being toward the low pressure passage, and yieldable means exerting a force on said valves toward the smaller valve seats.

6. A reversing valve mechanism comprising high and low pressure passages through which the fluid flows in only one direction, a pair of reversible flow passages through which the direction of fluid flow is to be alternatively reversed, a pair of reversing passages each of which is connected at one end to said low pressure passage and at their other end to said high pressure passage, each of said reversing passages having opposed valve seats disposed axially thereof and one set of seats being toward said high pressure passage and the other opposed set of seats being toward the low pressure passage,-double seating valves for said seats, said reversible flow passages communicatingwith said reversing passages at points intermediately of said opposed valve seats, whereby when'one of saidvalves is seated against the high pressure side and the other ofisaid valves is seated against the low pressureside then one of said reversible flow passages is connected with the low pressure passage and the other of said reversible flow passages is connected with the high pressure passage, or viceversa when said valves are reversely seated, valve stems extending axially from said valves on the side seating toward said low pressure passage, sealing means for said stems and valves whereby said sealingmeans is always subjected to low pressure in either direction of fluid flow through said reversible flow passages, said valves having differential valveheads and opposed valve seats, the smaller valve head and seat being toward thehigh pressure passage and the larger valve head and seat being toward the low pressure passage, and yieldable means exerting a force on said valves toward the smaller valve seats, said differential valve heads and yieldable means being so proportioned that the valves remain seated on either of their seats once the valves are moved thereto. v

7. A reversing valve mechanism in combination with a compressor-condenser-evaporator circuit comprising high and low pressure passages connected respectively to the compressor discharge and inlet and through which the fluid flows in only one direction, a pair of reversible flow passages connected respectively to the condenser and evaporator and through which the direction of fluid flow is to be alternatively reversed, reversing passages for interconnecting said high and low pressure passages with said reversible flow passages, a pair of reciprocable valves having substantially parallel operating stems, and floating actuating means for moving said valves in opposite directions including means for insuring simultaneous movement of said valves.

8. A reversing, valve mechanism comprising high and low pressure passages through which the fluid flows in only one direction, a pair of reversible flow passages through which the direction of fluid flow is to be alternatively reversed, reversing passages for interconnecting said high and low pressure passages with said reversible flow passages, a pair of reciprocable valves having substantially parallel operating stems, a floating lever pivotally connected toeach of said valve stems, and means providing a floating fulcrum adapted to assume a temporarily fixed position during actuation of said valves thereby to insure simultaneous movement of the valves in opposite directions.

9. A valve mechanism comprising a pair of simultaneously movable valves one of which moves in a direction opposite to the other, a floating lever for actuating said valves, and means providing a combined floating and temporarily fixed fulcrum for said lever to insure synchronous movement of said valves.

J OSEPH R. ZWICHJ.