Патент USA US2112791код для вставки
March 29, 1938. ‘ N. M. SMALL ET AL RIEFRIGERATING SYSTEM Filed March 28, 1936 2,112,791 \ 2 Sheets-Sheet l March 29, 1938. N. M. SMALL ET AL 2,112,791 REFRIGERATING SYSTEM Filed March 28, 1956 2 Sheets-Sheet 2 gwvcntom Kw» Aida/,4 fan @543 tau-1,22. ~ Gnome/1s Patented Mar. 29, 1938 ' 2,112,791 UNITED STATES PATENT OFFICE 2,112,791 REFRIGERATING SYSTEM Norman M. Small and Leon Buehler, Jr., Waynes boro, Pa., assignors to Frick Company, Waynes boro, Pa., a corporation of Pennsylvania Application March 28, 1936; Serial No. 71,485 .15 Claims. (01. 62-2) This invention relates to refrigerating systems ?uid pressure in accordance with this .invention. and more particularly to capacity control means for refrigerating compressors which are auto loading valve for returning the capacity control matically operable in accordance with conditions in the refrigerating system. In refrigerating plants a plurality‘ of compres Cl Fig. 2 is a sectional view of an automatic un means operating ?uid back to the fluid supply source. ' Fig. 3 is a vertical sectional view through a‘ compressor cylinder and one of the capacity con sors have been installed in which case one or more compressors can be shutdown during cool or cold trol ports in connection with ?uid pressure oper seasons and thus reduce ‘the refrigerating ca- _ ating mechanism. Fig. 4 is a sectional view of a modi?ed form 10 pacity of the compression side of the plant. However owners frequently desire to have all the of the fluid pressure operating mechanism for compressor capacity in a single unit with means the capacity control ports. Fig. 5 is a fragmentary sectional view showing for varying the volumetric displacement and the a modi?cation of part ‘of the unloading valve present invention relates to this type of installa shown in Fig. 2. _ 15 15 tion. Referring to the drawings this invention is Capacity control using the method of reducing the effective stroke of the compressor by by-pass ing part of the gas in the cylinder between the piston and discharge valves to the suction side ,20 of the compressor is old in the art and is not ' claimed as a part of this invention. The present invention relates particularly to capacity control for refrigerating compressors al though it may be used to equal advantage for air N.) Cl compressors, gas compressors,_ and other types‘ of ?uid compressors. An object of the invention is to provide means whereby the volumetric displacement of a com~ pressor can be controlled by either hand or by 30 automatic means. 1 Another object of the invention is to provide means for varying the volumetric displacement of a compressor automatically controlled by tem perature responsive means. Another object of the invention is to provide in a refrigerating system automatically operable means for operating compressor capacity control means in accordance with temperature of the re frigerant in the low side of the system. A further object of the invention is to provide in a refrigerating system means for operating‘ compressor capacity control means in accord ance with the vtrue saturated temperature of re frigerant in the low side of the system which cor 45 responds “to the back pressure of the expanded gas regardless of what the superheat temperature of the expanded gas in the low side of the system may be. - shown by way of example applied to a two cylinder compressor I0, however, the invention is appli cable to a_single cylinder compressor or of any number of cylinders. In the arrangement shown 20 the compressor is provided with a crank case I I, and a suction conduit I2 communicates with the compressor intake chamber I3. The compressor is provided with the usual discharge valves lo cated in the valve head I4 in the cylinder head as shown in Fig.3 and compressed gases are con- . ducted through a discharge line I5 leading to a condenser and receiver I6. From the receiver re frigerant ?uid is conducted through a hand con trol valve Mia and conduit II to an evaporator I8 30 which may be a cooler of any desired type, an ex pansion valve I8a controlling the discharge of liquid refrigerant thereinto. The gaseous re frigerant is then returned from the evaporator to the compressor through the suction conduit I2. As shown in Fig. 3 each cylinder is provided with a chamber I9 extending upwardly from the intake chamber I3 towards the head of the com pressor, and the intake chamber I3 is shown pro vided with an inlet port 20 communicating with the interior of the compressor cylinder 2| beneath the piston 22 therein; this piston is provided with the suitable types of sealing rings'and valves as indicated. In order to vary the compressor ca pacity a port 23 communicating through the wall of the cylinder 2| with chamber I9 is positioned to provide ~the required capacity reduction of they compressor. This port provides communication Other objects, details and advantages of our ' with the cylinder 2| above piston 22 with the invention will be apparent from the following chamber I9 so as to permit gas to ?ow from the description of the embodiments thereof shown in cylinder therethfough into the suction chamber I3 and through the suction port 20 during a the accompanying drawings, wherein: _ 'Fig. 1 is a perspective view of a refrigerating portion of the upward stroke of the piston. As indicated, piston 22 has moved upwardly to the ' system showing a compressor provided with ca 55 pacity control means automatically operated by upper edge of port 23 to close the communication 2 2,112,791 with chamber l9 and ‘on further upward move ment it operates to compress the remaining gas‘ ' in the compressor cylinder 2|. The distance the edge ‘of the port 23 is lo cated from the head of the compressor depends upon the amount of capacity reduction desired, ' for example, in Fig. 3 it is located at ?fty per cent of the stroke of the piston which gives ap proximately ?fty per cent capacity reduction. If ; 10 a greater capacity reduction is desired the up per edge of port 23 must be closer to the head of the compressor, and for a less capacity reduc tion the port must be lower in the cylinder. The position of the port in accordance with the re v15 quired capacity reduction is preferably deter mined and ?xed at the time the compressor is constructed. As shown in Fig. 3 a valve cage 24 is mounted in ?anges 25 formed in chamber I9 and it extends 20 through an aperture in the exterior wall thereof. The inner end of cage 24 seats on a gas tight gasket 26 between it and the compressor cylin der wall. Cage 24 is provided with a port 21 communicating with port 23 into the interior of the cylinder and ports 28 communicating with chamber H) which ports provide passageways through which gas may be permitted to ?ow as stated above. This cage 24 acts as a guide for a valve 29 slidingly mounted therein and which is 30 operable to close the passageway into the com surrounding plunger 39 which seal as shown includes a ?exible packing ring and a retainer ring cooperating therewith and secured to the end wall of casing 32' by means of screws or‘ the like. , It will be noted in the foregoing valve equip ment, which is a preferred construction although other forms can be employed for the purpose of this invention, that with the hand control in the position shown in Fig. 3 the Valve 29 closes port 10 23 for the full volumetric capacity of ‘the com pressor, but when the hand wheel is turned to disengage the stem head 35 from piston 3| valve 29 will be forced by the compression in the cylinder to an open position pushing with it 15 piston 3| in its cylinder casing 32. Piston 3| is adapted to be operated by ?uid pressure be hind it entering cylinder 32 through a ?uid con duit 43 communicating therewith. Cylinder 32 is also provided with ?uid return conduit 44 20 communicating with the other side of the piston and as shown in Fig. 1, the ?uid return conduits for each cylinder 32 are interconnected between the various cylinders and conduct the ?uid to the compressor crank case, although any suitable 25 source of ?uid supply‘ may be employed other than the crank case if desired. The ?uid con duits 43 of the cylinders 32 are interconnected and coupled with a ?uid pump 45 which has a supply conduit 45 leading to it from the source 30 pressor cylinder, thus causing the compressor of ?uid supply,—as shown the crank case M of_ to operate under full capacity. the compressor. ' As shown valve 29 is held closed by a' plunger 30 extending from a piston 3| which is slid 35 ingly mounted in an operating cylinder casing 32 which is secured by means of bolts 33 to the outer wall of chamber l9 with a gasket 34 of circular cross section between the end of the cylinder member 32 in the wall of the cham ber. This gasket forms a gas tight seal and permits easier alignment of the cylinder with the valve cage chamber for the valve 29. Piston 3| may be held in the valve closing position as shown by the engagement of the head 35 on a 45 stem 36 which is provided with a manual operat Fluid pump 45 is shown operatively connected by means of a coupling 41 with an electric motor 43 which receives its operating current from a suitable source of electric power supply indicated by electrical conductors 49 through a switch 5|] in the circuit‘ for controlling the operation thereof. Switch 59 controlling the operation of the motor driven pump is actuated by a bellows 5| by either temperature or pressure of a storage room or any part of a plant in which'the tem perature or pressure is to be maintained within close limits. As shown in Fig. 1 this bellows 45 is contolled by a thermal element 52 cooperating with the suction conduit |2 of the compressor. In this arrangement of switch control 50 the operation of the motor driven pump is automati cally controlled so that its operation is in ac 50 ing hand wheel 31. Hand wheel stem 36 is provided with threads v38 engaging corresponding threads 39 in a cylin der closing head 40, and the outer end of head 40 60 is provided with a packing member 4|. It will be ‘noted that when hand wheel 31 is turned to dis ' cordance with the temperature of the refrigerant engage the head 35 from piston 3| and is moved in the suction line, and'in accordancev with the outwardly therefrom the rear of the head 35 conditions required the piston 3| is operated to which'has a seating surface makes contact with a close port 23 by valve 29 without using the 55 complementary seat 42 formed in head 40 making hand control wheel 31, the hand control wheel a gastight joint therewith whereby the packing being operated to its outermost position to allow element 4| may be inserted or renewed. piston 3| to reciprocate in its cylinder for the Referring to Fig. 4 an operating cylinder cas automatic operation thereof. Thus the auto ing 32', of the same construction as shown in matic operation of the compressor will take 60 Figure 3, is shown with a modi?ed form of piston place irrespective of weather conditions such as 3|’ and other slight changes; with the exception’ temperature and humidity .which normally have of these modi?cations, the parts are the same as those illustrated in Figure 3 but the stem 36 is shown in its outer position with the head 65 35 seated in the seating surface in head 40 as previously described. In this structure piston 3|’ is provided with a piston packing 3|b in the form of a molded cup packing instead of piston rings 3|a such as provided for piston 3|. This 70 cup packing is secured to piston by means of a cup retainer 3|c. This in turn is held in place a decided effect on the compressor capacity, and the compressor will operate at full discharge ca pacity or at its intermediate discharge capacity in accordance with the control of switch 5| 65 which, as shown in Fig. 1, is controlled by tem perature. ‘ Accordingly in the; operation of the control mechanism when the temperature drops below a predetermined point the switch opens and breaks 70 the current to motor 48 thereby stopping it. The _ by a nut 3|d on the end of plunger. 30 extending . ?uid supply is consequently stopped and the fluid through piston 3|,’ which also maintains piston in the piston cylinder is released through conduits elements assembled on this plunger. The cas ing 32' is also provided with a‘closure seal 30a 43, returning by way of a check valve 53 to con duit 44 back to the source of ?uid supply. This 75 3 2,112,791 _ allows the compressor to force valves 29 to open position and consequently unload the com pressor to the predetermined degree (?fty per cent or in accordance with the position of port 22 with respect to the compressor cylinder head) through the various ports back to the suction of the compressor. ' chamber surrounding the thermal bulb. This .is for the purpose of giving a saturated tempera ture around the bulb regardless what the super heat temperature may be in the ‘suction line ‘ itself. Accordingly, a true saturated temperature corresponding to the back pressure is obtained be cause the temperature of the gas expanded must correspond to the back pressure in the suction line, and this true saturated temperature is ob tained because the gas so expanded does not mix 10 with the superheated gas until it passes down to the suction line. However when valve 64 is closed Check valve 53 is closed by a ?uid pressurein the conduit 43. This valve as shown in Fig. 2, 10 comprises a casing which includes an inlet port 54 and outlet port 55 which ports are connected to conduits 43 and 44 respectively. Inside the casing is a reciprocable valve member 55' having the capacity control of the refrigerating system will operate in accordance with the temperature an elongated spirally grooved passageway 56 ex of the gas in the suction line from the evaporator 16 15 tending from its upper face to the lower portion instead of the saturated gas temperature. Thus thereof whereby ?uid may escape from the inlet the system may be operated under either condi or high pressure side to the outlet or low pres sure side when the pump is inoperative. This tion by operating with valve 64 opened or closed . ' valve member has a plunger 51, the end of which as desired. It will be obviou'sto- those skilled in the art 20 seats in a valve seat 58 in the casing, and a spring I 20 59 therein tends to force the valve upwardly to that various changes may be made in our device open the port through valve seat 58. In the , without departing from the spirit of the inven upper portion of the valve casing is an abutment tion and herefore we do not limit ourselves to what is shown in the drawings and described in member 60 having a projection 6| thereon with in the casing against which the movable valve the specification but only as indicated in the ap-'-" pended claims. .. member 55’ is adapted to engage when forced up wardly by a spring 59. ,The position of the pro je'ction 6| in the valve casing determines the up per limit of the movement of valve member 55'. A check valve 53 with modifications is shown in Figure 5. Due to inequalities of tension of 30 ' spring 59, a compensating spring 59' is positioned above valve member 55’ and in this arrangement the abutment member 60 with its projection is replaced by a head 60' threaded into thecheck valve casing in place of the member 60. This head carries a stem 60a having a threaded en gagement therewith at 601) and a packing mem ber 690 forms a ?uid tight seal around stem 60a. Stem 60a has an enlarged spring engaging mem 40 ber 6|’ on its inner end for engaging spring 59' and its upper end is formed for receiving an op erating tool such as a kerf 60d for receiving the blade of a screw driver. By turning stem 60a in vor out tension on spring 59' may be varied and by such adjustment compensation for inequali ties of. spring 59 is provided. - When the temperature rises switch 50 is‘auto-' matically closed, starting motor 45 so that pump 48 is operated to start the circulation of ?uid through conduit 43 to the cylinders of pistons 3|. Check valve 53 has its valve member 55' closed against the spring 59 by the ?uid pressure on ac count of the resistance of the ?uid passing through this valve. This in turn puts pressure through the branch conduits '43 leading to the piston chambers for each compressor cylinder and against the pistons 3| which are forced in .65 We claim: ' 1. In a refrigerating system, a compressor, capacity control means constructed to operate only during a portion of the compression stroke for varying the volumetric displacement of the compressor for varying the refrigerating capac- ity of the system, and temperature responsive means for controlling said capacity control means, said ‘temperature responsive means being constructed and arranged for actuation in ac cordance with the temperature corresponding to the pressure within the cooling element of the said refrigerating system. 2. In a. refrigerating system, a compressor, 40 capacity control means for varying the. volu metric displacement of the compressor for vary ing the refrigerating capacity of the system, man ual means for controlling the capacity control means, and temperature responsive means for controlling said capacity control means, said tem perature responsive-means being constructed and arranged for actuation in accordance with the temperature corresponding to the pressure with in the cooling element of the said refrigerating system. , .7 3. A refrigerating system including a com pressor, an evaporator and suction line for re turning refrigerant from the evaporator to the compressor and‘ capacity control means con 55 structed to operate only during a portion of the compression stroke for varying the volumetric displacement of the compressor for varying the wardly and thus the ports 23 by engagement of refrigerating capacity of the system, and means the valves 29 therewith and the compressor for controlling said capacity control means in ‘ accordance with the temperature-of expanded then operates at full capacity. Referring again to the thermal element 52 gas on the low side of the system. 4. A_ refrigerating system including a com-\ which cooperates with suction line l2 of the com pressor, an evaporator andsuction line for re pressor, it will be noted that this element is pref erably positioned in a small chamber 62 which turning refrigerant from the evaporatonto the 65 is closed at its upper end where the thermostatic bulb screws into it but is in open communication at its lower end with the suction line. A small compressor and capacity control means for vary ing the volumetric displacement of the compres sor for varying the refrigerating capacity of the liquid refrigerantline G3 conducting refrigerant system. and means for controlling said capacity ' control means in accordance with saturated gas 70 70 from receiver 16, shown connected with conduit 11, is connected with an expansion valve_64 which in turn discharges through a connecting pipe 65 into chamber 62 around thermal element 52. It will be noted that with valve 64 ?uid re 75 frigerant is discharged and expanded into this temperature on the low side of the system. - 5. In a refrigerating system, a compressor in cluding a compression cylinder and piston there in, capacity control means constructed to oper ate only during a portion of the compression 75. 4 2,112,791 , stroke to affect the volumetric displacement of the compressor for varying the refrigerating capacity of the system comprising a port in the sponding to the pressure within the cooling ele ment of the said refrigerating system. cylinder wall and a valve for closing said port, ?uid pressure means for closing said valve, and“ cluding a compression cylinder and piston there in, capacity control means for varying the volu metric displacement of the compressor for vary temperature responsive means for controlling the supply of said ?uid pressure means. 6. In a refrigerating system, a compressor in cluding a compression cylinder and piston there 10 in, capacity control means for varying the volu-. metric displacement of the compressor for vary ing the refrigerating capacity of the system com prising a port in the cylinder wall and a valve 10. In a refrigerating system, a compressor in- 4 - ing the refrigerating capacity of the system com prising a port in the cylinder wall and a valve for closing said port, a ported cylinder in which said valve is slidingly mounted, a piston reciprocably 10 mounted behind said valve and having means for engaging said valve“ to operate it to its closed position, a source of ?uid supply, a pump for sup for closing said port, temperature responsive plying said fluid behind said piston for closing 15 means for operating said valve to close the port said valve, a conductor for returning ?uid there from to said source of supply, and a check valve therein operable to return the ?uid therethrough to the source of ?uid supply when said pump is and to permit the valve to open, and manual control means for closing said valve, said tem perature responsive means being constructed and arranged for actuation inaccordance with the 20 temperature corresponding to the pressure with in the cooling element of the said refrigerating system. 7. In a refrigerating system, a compressor in cluding a compression cylinder and piston there in, capacity control means for varying the volu metric displacement of the compressor for vary ing the refrigerating capacity of the system com inoperative. 11. In a refrigerating system, a compressor, 20 capacity control means for varying the refrigerat ing capacity of the compressor, a ?uid supply source, means for placing the ?uid under pressure for operating said capacity control means to cause the refrigerating system to operate at full 25 capacity, _a conductor for returning ?uid there. from to said source of supply, and a check valve prising a port in the cylinder wall and a valve therein operable to return the ?uid therethrough for closing said port, temperature responsive to the fluid supply source when said ?uid pressure means is inoperative. 80 12. In a refrigerating system, a compressor means for operating said valve to close said port and to permit the said valve to open said port, and manual control means for operating said valve including a stem movable inwardly toward said valve to effect the engagement of said valve with said port in its closed position and mov-e able outwardly away from said valve to release the valve from the effect of said manual control means. 8. In a refrigerating system, a compressor in with ?uid pressure operated capacity control means, a source of ?uid supply and means for supplying ?uid therefrom under ‘pressure to said ?uid pressure operated control means, a con ductor for returning ?uid from said control means to said source of supply, and a check valve there in for unloading the operating ?uid and returning it to the source of ?uid supply when the pressure cluding a compression cylinder and piston there thereon is reduced. in, capacity control means for varying the volu— metric displacement of the compressor for vary ing the refrigerating capacity of the system com prising a port in the cylinder wall and a valve for operating said port, manual control means for closing said valve including a stem movable inwardly toward said valve and outwardly away 13. In a refrigerating system, including a com pressor with ?uid pressure operated capacity con-' trol means, a source of ?uid supply and means for supplying ?uid therefrom under pressure to said pressure operated control means, a conductor for returning ?uid from said control means to said source of supply, and a check valve therein for from said valve, a head on one end'of said stem arranged on one side to.form a control valve, unloading the operating ?uid therethrough com a control cylinder head with a packer through which said stem operates, and said control cyl inder head having a cooperating valve seat adapt ed to receive said control head valve and form a seal therewith when the stem is in its outer most position. 9. In a refrigerating system, a compressor in cluding a compression cylinder and piston there in, capacity control means constructed to oper ate only-during a portion of the compression stroke for varying the volumetric displacement of the compressor for varying the refrigerating capacity of the system comprising a port in the cylinder wall and a valve for closing said port, a source of ?uid supply, ?uid pressure means 65 for closing said valve, and means for controlling the supply of said ?uid pressure means, and means for returning the ?uid directly to the ?uid supply source when the pressure of the ?uid 70 pressure means is reduced so as to permit the valve to open by the pressure in the compressor and thereby cause the compressor to operate at lower capacity, said temperature responsive means being constructed and arranged for actua tion in accordance with the temperature corre 40 prising a valve casing having a cylindrical interior and inlet and outlet ports at opposite ends there of, a valve member therein operable to close the communication with the outlet port, said valve 50 including‘ a piston portion’ slidable in said casing, a spring under said valve member tending to move it from itsv closing position, and said piston por 55 tion having a restricted passageway therethrough permitting the passage of ?uid therethrough when the pressure of the ?uid is reduced. 14. In a refrigerating-system, including a com pressor with ?uid pressure operated capacity con 60 trol means, a source of ?uid supply and means for supplying ?uid therefrom under pressure to said pressure operated control means, a conductor for returning ?uid from said control means to said source of supply, and a check valve therein for. unloading the operating ?uid therethrough com prising a valve casing having a cylindrical in terior and inlet and outlet ports‘ at opposite ends, thereof, a valve member therein operable to close the communication with the outlet port, said valve 70 including a, piston portion slidable in said’v cas ing, a spring under said valve member tending to move it from its closing position, a spring over said valve tending to move in the reverse direc tion, means for adjusting the tension of the last 2,112,791 said spring, and said piston portion having a re stricted passageway therethrough permitting the passage of ?uid therethrough when the pressure of the ?uid is reduced. 15. In a refrigerating system, a compressor, capacity controlling means constructed to operate only during a portion of the compression stroke 5 of said compressor for varying the refrigerating capacity of the system, and temperature re-v sponsive means for controlling said capacity con trolled means. NORMAN M. SMALL. LEON BUEHLER, JR.