US2116802A - Refrigeration control apparatus - Google Patents

Description

3 Sheets-Sheet 1 M4 ov, A 3 ,v .4 n m e m, w m o@ kwa. Z w \7 w m P TUV. 5%. z m/ P. F. sl-uvERs REFRIGERATION CONTROL APPARATUS Filed oci., 24, 1955 SCL;`

Marlo, 1938. P. F. SHNERS 2,116,802

REFRIGERATION CONTROL APPARATUS Filed Oct. 24, 1935 5 Sheets-Sheet 3 leus v gmnoz PauZF az'vms* with the outlet pressure but in which provision is Patented May l0, 1 938 UNITI-:D4 STAT-Es 2,116,802 i aEFmGEaA'rIoN ooN'r'aoL APPARATUS Paul F. Shivers, Wabash, Ind., assigner to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation ofl Delaware- Applieation October 24, 1935, Serial No. 46,527

21 claims.

valve serves to-reduce the pressure of the refrigerant in passing from the condenser to the evan.- orator. In passing through the expansion valve from the high pressure side to the low pressure side of this system there is a tendency for the refrigerant .to form a certain amount of gasin `the valve drawing heat from the walls of the valve in so doing. In other words, asimilar action but on a kmuch smaller scale as that which takes place in the evaporator takes place inthe valve itself. The resultnof this is that there is a `tendency for frost to form on the outside of the expansion valve. The formation of this'frost so lowers' the temperature of the valve as to endanger the smooth operation ofthe same. Moreover, where thermostatic control means are employed, a lowering of the temperature at the valve results in the temperature at the valve being lower than the temperature at the control point. Where a thermostatic control means based upon the variationin vapor tension of a fluid is cm- `ployed, this cooling of the valve below the temperature of the control point tends to shift the control point to the valve itself thus giving an inaccurate temperature control'.

An object of -the present invention is to provide a refrigeration control system in which the control of the flow of refrigeration through the expansion valve is not dependent upon the temperatu're of the valve being higher than that loi` the desired control point.

A further object of the present invention is to provide a thermostatically controlled expansion t' valve mechanism in which the thermostatically controlled means is based on the,variation of vapor tension with temperature, andin which said control means responds Jonly to the temperature at the desired control point.

a refrigeration expansion valve mechanism in which provision is made not only for the usual.

control of the flow of refrigerant vin accordance made to prevent variations in the inlet pressure y flutedto allow the passage of fluid to the valve A further object of the invention is to provide .(ol. sz-s) vfrom causing a variation in the flow of Vrefrigerant through the valve. Other objects of theA invention will become apparent from the accompanying specification,

-claims and drawings, of Jwhich: 5

Figure 1 is a sectional view of one form of my expansion valve;

Figure 2 is a schematic showing of a refrigeration system embodying my expansion valve;

Figure 3 Vis a sectional view of a modified form of' my expansion valve;

Figure 4 is a section taken on the line 4-4 of Figure 3 in the direction indicated by the arrows. and l Figure 51's a sectional view of a further modification of my expansion valve.

Referring to Figure 1, the expansion valve mechanism comprises a valve housing I0 having inlet connection II and outlet connection I2. AThe inlet connection II comprises a longitudinally extending projection I3 of the valve body which is provided with an elongated cylindrical charnber I4 therein. A screen I5 is `located in said chamber and is retained'in place by a screwthreaded nipple I6 which is provided with a 25 threaded lower end I1 to facilitate connection with any suitable conduit. The nipple I6 is provided with a central passage I8 which is in communication with a passage I9 in the wall of the valve body I0 through the screen I5. 30

The valve body is provided -with an inwardly extending portion 20. This portion 20 is provided with an aperture in which is screw-threadedly mounted a valve seat and guide member 2i. The member 2l is provided with a central aperture 22 which communicates with the interior of the guide 23. A shoulder is provided by the junction of aperture 22 with the interior of the guide 23 and'forms the valve seat proper. The member 2i is further provided with an external ange 25 which provides an abutment shoulder for a, spring 2B. 'I'he valve proper comprises a cylindrical member 24 having a conicaLend 21 which forms a valve head. The member 24 is y seat between the valve stem and the wall of guide 23. At its lower end the valve is provided with a circular disc 29 which forms an abutment shoulder Vfor the other end of spring 26. As will be readily seen, the valve is biased to an open position by the action of the spring 26. The inwardly projecting portion 20 is provided with a passage 30 communicating with aperture 22 and with the outlet I2. y

The valve flange 2! is in `engagement with a 55 Cil relationship two opposed expansible chambers` 33 and 34. The expansible chamber 33 comprises a corrugated element 35 whose .lower end is soldered at 28 to a disc 35. At' the opposite end, the corrugated diaphragm 35 is soldered at 38 to the ilange of a nipple 39 The nipple 39 is secured to a threaded collar 40 forming the upper closure member of the valve body l0 through a nut 4I which clamps said nipple against a flange 42 of collar 40. A washer 44' of any suitable material is provided between the nipple 39 and flange 42 to Iprevent escape of uid from the interior of the valve body. A bolt member 44 is threadedly engaged at its lower end with the disc 36 and is provided at its upper end with a head 45 having grooves 46 therein to permit the passage of fluid between .the head 45 and they internal wall of nipf vlows element and serves to urge the same to expanded position.

Connected through the disc 41 and nipple 39 with the interior of chamber 33 is my novel thermostatic means generally indicated by the reference numeral .50. This means comprises a bulb- 5I into which extends a tube 52. The tube 52 extends slightly more than half-way into the bulb 5l and isI held in a central position by means of an apertured disc 53. -Tube 52 is connected at its opposite end with the Ydisc 41 extending through the aperture thereof and secured thereto by any suitable means shownfor purposes of illustration in the drawings as a flared connection. In the upper portion of the bulb 5I, there is located a substance 54 which is normally in a vaporous state. While the particular substance which I employ is not of importance, it being well known in the art to employ such vaporous materials, I have found it satisfactory to employ a substance similar to that used for the refrigerant. 'Thus,

where sulphur dioxide is employed as a refrigerant, I have found it satisfactory to employ this substance for the vaporous substance in the bulb. Filling the rest of the space in the bulb, the interior of the tube 52 and the interior of the expansible chamber 3 3 isa substance 55 which re-` mains liquid, throughout the range of temperaltures to which it'will be subjected and which hasl a. relatively low co-eicent of temperature expansion. Any suitable substance whicho has the above properties is satisfactory. I have found a mixture of'ethylene glycol, alcohol and water to be satisfactory for this purpose, although this is merely one of any numbe of substances which will immediately suggest themselves to one skilled in the art as suitable for the purpose. Since the only vapor is located in the bulb and since the liquid 55 has a comparatively low co-eicient of temperature expansion, changes in temperature occurring at some other point than adjacent the bulb 5I will have no effect upon the controlling action of the thermostatic means 50.

The expansible chamber 34 comprises a corrugated diagram'element 56 which is soldered to a circular plate 51 at its upper end t 58. The lower end of the diaphragm member 56 soldered at 59 to the interior of the valve body l0. The valve body l0 is closed at its lower end with a threaded cap 60 having an upwardly extending internally threaded stud 6 I. A screw 62 is threaded through said stud and abuts a cup-shaped member 63 having a ilange 64` at its lower end which flange serves as an abutmentmember for a spring 65. The spring bears. at its other end against the movable plate 51 and serves to urge the expansible chamber 34 towards its expanded position. The screw 62 serves as a means for adjusting the tension of spring 65. A passage 66 extends downwardly through the wall of the valve body I Il and serves to establish communication between the interior Vof expansible chamber 34 and aperture 30 of stud 20 adjacent the valve outlet. 'I'his passage results in the interior of chamber 34 be ing subjected to the outlet pressure.

It will be noted that the incoming refrigerant -passes into a chamber which. completely surrounds the inwardly projecting portion 20 and the valve seat and guid member 2l and which extends substantially he full length of the valve body. Since the refrigerant entering the expansion valveis still comparatively warm, the provision of this large chamber in the valve body in direct communication with the inlet results in the presence of a large body of relatively warm fluid l completely surrounding the,N valve seat, the valve and valve guide on all sides and ofsu1licient size so as to serve to prevent the temperature of the valve body from falling unduly. `In this manner the tendency of my valve to frost over is negligible. Y v

The diameter of diaphragm- 35 is slightly 'greater than that of diaphragm 56 as indicated in the drawings. Y'I'he result of this is that any increase in inlet pressure will have a slightly greater eifectvupon the chamber 33 than' upon chamber 34.- 'I'hus if the inlet pressure rises both diaphragms will tend to be compressedagainst the action of the respective springs associated therewith. Since, however; the diaphragm 33 has a larger area exposed to the inlet pressure than diaphragm 34 the tendency towards compression of chamber 33 will be greater than that of diaphragm 34` with the result that the yoke 32 will be moved upwardly thus moving the valve towards its seat, In this manner, the increase in inlet pressure tends to reduce the.openingof the valve and hence the `flow of refrigerant through the valve is maintained constant in spite of such change in inlet pressure. It will be obvious that the, opposite action takes place when the inlet pressure decreases and that in this case also the movement of the valve is such as to tend to maintain the flow of refrigerant constant in spite of such decrease cin inlet pressure.

Referring to Figure 2, I have shown my expan- 'sion valve mechanism embodied in a more or less conventional refrigeration system. The system comprises a compressor 10 operated by a motor 1|, whose action is controlled by a thermostat 12 which is located in a space to be cooled. A conduit 13 serves to convey the compressed refrigerant from the compressor to a condenser 14. The condenser 14 may be of any suitable conventional construction and is provided with inlet and outlet pipes 15 and 16, respectively, for the circulation oi a cooling medium therethrough. The expansion valve is designated by the reference numeral 11 and is connected through a conduit 18 with the outlet of condenser 14. I'he outlet of expansion valve 11 is connected with the evaporator coil 19 which in turn is connected through a conduit 80 with the Vinlet of compressor 10.

The thermostatic bulb I of my expansion valveentering the evaporator the refrigerant is evapo` rated and in so doing absorbs heat from 'the walls and surrounding atmosphere of coils 19., thus. servingto lower the temperature adjacent the same. Due to the connection between the outlet `|2 and the interior of expansible chamber 34A when the compressor starts operation thus lowering the pressure in the evaporator 19, the pressure within the expansible chamber 34 is decreased with the result that the expanding effect of chamber 33 becomes greaterr than that of 34 so that yoke 32 is moved downwardly thus moving the valve'laway from the valve seat permitting the passage of refrigerant thereto. As soon as the pressure at the inlet of the evaporator begins to ris'e,the pressure in chamber 34 will likewise begin to rise and the valve will be moved towards a closed position. ,In this way my valve serves to controlthe flow of refrigerant in accordance with the outlet pressure which is equivalent to y the pressure atzthe inlet of the evaporator 19.

The outlet pressure maintained by the valve may be adjusted by varying the tension of spring 65 through adjusting screw 62.

As the temperature surrounding the evaporator 19 decreases due to the evaporation of the refrigerant, the temperature surrounding bulb 5| will likewise decrease with the result that the vapor tension in bulb 54 is decreased. Through the liquid 55, this decrease in pressure is transmitted to the interior of, bellows 33, causing an upward movement of yoke 32 and a correspond# ing upward movement of valve 21 towards closed position. In this -manner .myvalve serves to. maintain a constant temperature at the .outlet of the evaporator coil and since. the pressure is dependent upon the temperature, to tend to maintain a constant pressureat'the outlet of the evaporator.

. In the event that for anylreason the pressure in the inlet of valve. 11 changes my valve will act to prevent such change in inlet pressure from affecting the now 'of refrigerant, inthe manner previously discussed.'

Since the valve body is-maintained comparatively warm byreason of the large body of warm refrigerant therein,'there -is no tendency for the valve to frost as previouslyexplained.' This in itself decreases the liability of the thermostatic control means 50 being rendered inaccurate by reason of a low temperature in the expansion valve. In addition, the vuse .of a substance which remains in liquid state in the tube, in the bulb and in the expansion chamber within the valve eliminates the possibility of the operation of the thermostatic means being aiected if for any 4reason the temperature of the valve should bccome lower than that surrounding the bulb.

It will be seen that" my valve automatically compensates for any variation in inlet pressure and. automatically controls the flow of refrigerant in accordance with variations in the pressure .stem through a reduced portion |31.

in the evaporator and the temperature at the outlet side of'said evaporator. I, moreover, have provided a valve with which one does not experience the usual diiculty of frosting encountered-with valves of this type. This, together with my novel filling for' the thermostatic bulb assembly resultsin the-valve being provided with -thermostatic control means which is responsive tothe temperature only at the vdesired control point. .u

In Figures l3 and 4 of my' drawings, I have illustrated' a modified formf my device.1 Referring 'to Figure 3, the valve body is designated by the reference numeral and is provided with an inlet II| and an outlet ||,2. The valve body IIIJ' is provided with a longitudinally extending projection I I3 which is provided with a chamber ||4 therein housing a screen ||.5. The screen ||5 is retained inv place by al nipple ||6 threadedly ngaged to the member ||3. The nipple I6 is provided at its lower end with a threaded portion ||1 which,V serves to facilitate the connection of said nipple to a suitable conduit. The nipple I I6 is further provided with a central aperture ||8 which is in communication with an inlet aperture IIS in the valve body proper, through the screen ||5. A set screw .|20 closes oil' an entrance tothe passage ||9 which entrance is provided for the purpose of facilitating the removing of any obstruction which may enter the passage ||9 in spite of the presence of screen I I5. The valve body I Ill is divided intotwo portions by a central partition |2|'. The partition is prol vided with a central aperture |22 into the lower end of whichis threaded a valve seat and guide member |24. Member |24 is provided exteriorly with shoulders |25 and |26 which engage with corresponding' shoulders in the partition |2|.

The aperture |22 of thepartition |2lis provided with an enlarged portionat its lower end which is of greater diameter than the exterior diameter of the member |24 between shoulder |25 and shoulder |26, thus providing anannular passage |28 between the enlarged po'rtion of passage |22 and the valve seat and guide member 24. Member |24 is provided with an aperture |29 which communicates at its lower end with the interior of a cylindrical portion |.3I of the member, which constitutes the valve guide. The shoulder formed by the junction of aperture .|29 with the interior ofthe guide |3| serves as a valve seat. The valve proper comprises a stem portion |33 which is fluted to permit the passage of uidbetween saidy stem and the interior of guide |3I.

The upper end of said stem is conical in form as indicated at |35 to provide a valve head'.. Atcached to the valve stem atits upper end is a plunger extension |36 which is connected4 to said At the junction of the reduced portion |31A with the main body portion of the plunger |36, the Vshoulder loc'ated at said junction is recessed slightly as indicated at |38 for a purpose to be presently described. A

The lower end of casing is closed by means of a screw cap |40 which is`provided with a centrai aperture in which is mounted an internally threaded plug |4|. Mounted in said plug |4| isa screw |42 the end of which is in engagement with the upper end ofva diaphragm |43. The lower end of the diaphragm is soldered to the cap |40 at |44. Ihis diaphragm constitutes a seal to prevent huid from escaping through the adjustplug |4I. VA spring |45 bears at its lower end against the upper end of the. diaphragm and bears at its upper end against a spring guide |46 which spring guide is provided with a perforated, cup-shaped aperture portion |41 which abuts against the end of the valve stem. The spring |45 thus serves to bias thevalve towards a closed position.

The partition |2| comprises an annular passage |48 which is shown in full lines in Figure 4 and partly in dotted lines in Figure 3. A's will be evident from the showing in'these two figures, this annular passage |48 extends downwardly to the lower edge of the partition, |2| except for two portions |49 and |50 of the partition [2| which portions contain the inlet passage ||9 and passages' |5| and |52 leading to the outlet ||2 and to the upper portion of the valve, respectively. 'I'his annular passage |48, as shown in Figures.3 and 4, is connected by diagonal passages |53 with the annular chamber |28.

The upper end of the valve bodyll is closed by a screw cap |54. This cap |54 is provided with a central aperture through which extends a nipple |55 which is in threaded engagement at its upper end witha nut |56'which serves to clamp the nipple |55 against the inner surface of collar |54. -A washer |51 of any suitable material is interposed between the nipple and collar to prevent escape-of fluid from the valve housing. Nipple 55 has a central flange |58 to which is soldered at |59 a. corrugated diaphragm |60. This diaphragm is soldered at its lower end to a -disc |66 which bears against the upper end of plunger |36. The disc |66 is provided with-an internally threaded stud |61. A bolt |68 is in -threaded engagement with said stud at .its lower end and is provided at its upper end with a head |69 grooved to permit the passage of fluidV between the head and the interior of nipple |55. 'Ihe nipple |55 is provided with an internally extending fiange |10 which is adapted to engage a head of bolt |68 and limit the downward movement thereof. The upper end of the aperture through the nipple |55 is partially-closed by means of a collar |1| which is secured to the nipple |55 'in any suitable mannersuch as by being sweated thereto. It will thus be seen that disc v|66 constitutes a movable wall of a cham-` ber |12, the expansion of which is limited by the engagement of the head of bolt |68 with ange |10.

The thermostatic means |13 comprises a. bulb |14 connected by a tube |15 to the interior of chamber |12. As in the preceding case, the tube |15 extends slightly more than half-Way into the bulb. Similarly, as in the preceding case, the bulb contains a. substanceil'l in vaporous condition and the remaining portion of the bulb, the tube |15 and the interior of the expansiblc chamber |12 are lled with a fluid |80 which remains in a liquid state throughout the temperature range to which it is subjected and which has a relatively low co-eicient of temperature expansion. These substances employed may be the same as those suggested in connection with the previously described form of my device. The

bulb |14 is shown as provided with a meansf-forV initially lling the bulb with liquid andvapor which comprises a section of tubing which is crimped as at |19 after the assembly has been lled to prevent escape of the iluid substances.

The refrigerant owing to the valve seat enters through the aperture ||8 passing therethrough into the screen ||5 and through the screen and aperture Il! tothe annular chamber |28. It4

will be noted that this/chamber immediately surrounds the lvalve seat so that the valve seat is directly surrounded with the incoming refriger- .ant which is relatively warm. From the annular to the valve seat through the apertures in spring guide |41 and the ilutes in the valve stem |33. If the valve is open, the refrigerant passes through the valve d the valve seat with consid# erable force due tothe high pressure in the inlet side thereof and is thrown against the shoulder |38 and from there passes through aperture |5| to the. outlet. As previously explained, the shoulder .|38 is recessed slightly. The object of this recessing of said shoulder is to prevent the refrigerant issuing through the valve from passing between the plunger |36 and the surrounding partition 2| into the upper portion of the valve chamber. By recessing the shoulder in this manner'the `liquid is deflected towards the central portion of the plunger assembly and from there passes through aperture 5| as previously explained. The upper portion of the valve casing is in communication with the outlet through' passage |52 and the pressure maintained therein tends to correspond to the outlet pressure. Since.

the exterior of diaphragm |60 is subjected to a pressure corresponding to the outlet pressure any decrease in said outlet pressure, such as by the starting of the compressor, rwill result in the ex-l pansion of said chamber thus urging the valve further away from its seat. Conversely, upon the outlet pressure rising the chamber will contract and the valve will be urged closer towards its seat by the action off the spring |45. Thus the valve, in a manner similar to h the previously described embodiment, tends to at described in` maintain a constant outlet pressure, the value' of which may be adjusted through'spring adjusting screw |42. If some means such as a recessed shoulder |38 were not provided to prevent the refrigerant from being forced bet'ween plunger |36 and the partition |2|, the pressure in the upper portion of the valve body acting on the y exterior of diaphragm would tend to be higher than the outlet pressure due to the force with' I which the refrigerant issues from the valve seat. This would result in the valve being controlled as though a higher outlet pressure existed than was actually the case.

The action of the thermostatic means |13 is substantially the same as that in the case of my previously described species. Upon the temperature at the control point, which is preferably the outlet of the evaporator, rising, the vapor tension within the bulb Will-be increased and the increase in pressurecaused thereby will be transmitted to the liquid in the interior of the expansible chamber |12. This will cause plunger |36 to be moved downwardly thus moving the valve in the direction of an open position and permitting more refrigerant to flow through the valve. Similarly,

when. the temperature adjacent the outlet o1' thel vevaporator decreases, an opposite action takes pace. v

Thus, as in my preceding form, I have provided a valve wherein the iiow of refrigerant is controlled in accordance with `the outlet pressure whichcorresponds to the pressure in the evaporator coil. I have, moreover, provided a valve in which means is provided for controlling the position of the valve in accordance with the temthereto.

perature at the outietfdf the evaporator. This form of my valve islikewise designed to prevent frosting thereof and is, moreover, provided with a temperature control means which is effecf tive even if such frosting should take place.

In Figure 5, I have shown a third modiiication of my expansion valve mechanism. In this figure, the valve body is indicated by the reference character |90 and is provided with an inlet I9I and an outlet |92. The inlet |9I is constituted by a cap |93 provided at its lower end with a nipple |94. The cap |93 has a centralaperture |95 throughthe nipple portion thereof which communicates withl the interior of a screen .|96.

The valve body |90 is separated by a transverse partition |91 into upperv and lower portions. In

the center of the partition |91 an aperture is` provided in which is mounted a member |98 which functions as a valve seat and guide member. The member |90 is provided with a central aperture |99 which communicates with the' interior of 'a cylindrical portion 200 which 'constitutes a valve guide. At the junction of said aperture |99 with the interior of the guide 200, a shoulder is'provided which constitutes a valve seat. Slidably mounted within the guide 200' is a valve which comprises a ribbed stem portion 202 and a conical valve portion 203. The valve portion 203 is provided with an integral pin extension 204 at its upper end. Bearing lagainst the lower end of the valve stem is aV cup-shaped lspring guide 205. A spring 206 A.bears at its upper end against the ange of spring guide 205 and at its lower end against the shoulder of a lowerV spring guide 201 which is mounted on the upper end of screen |96. Thus spring 206 serves to bias the valve towards a closed position and to simultaneously hold the screen |96 in position. 4

The upper end of the valve body |90 is enlarged as at 200 and terminates in a screw-threaded flange 209. A diaphragm 2I0 is soldered at its lower end to a 'disc 2| I, and at its upper end to an annular plate 2I2. This diaphragm is secured in position through the annular plate 2I2 which is in engagement with a sealing washer 230 on an internal shoulder 2|3 of the valve body and is clamped to said shoulder by aninternal annular member 2I4 in threaded engagement with the interior of ange 209 of the valve body. The -plate 2| I attached to the lower end of the diaphragm 2I0 bears against the upper end of a` pin 204. A cap 2I5 isin loose-threaded engagement with the interior of flange 209 and is provided at its lower end with a perforated central apertured plate 216 which is secured thereto in any suitable manner such as by being sweated A spring 2|1 bearsvat its upper end against the plate 2|6 and at its lower end against the plate 2|I thus serving to expand' the diaphragm and to hence contract a chamber` 2|8 which is constituted by the upper portion of the Y valve housing by the diaphragm 2I0, and bythe upper and lower plates 2I| and 2I2. The cap 2I5, by reason of the loose-threaded engagement with flange 209, constitutes a means for adjusting the tension of spring 2|1.

An expansible chamber 225 is located in the cap 2I5 and comprises a corrugated diaphragm member 2I9 soldered at its upper and lower ends to plates 220 and 22 I. The lower plate 22| ls provided with a recessed downwardly extending bossV 222 and a pin 223 has one end thereof seated in the recess of said boss. The lower end of pin223 is seated in a recess of a box 224 and on the plate 2| I. In this manner, a

lconnection is provided between the movable plate 22| and the movable disc 2|I whereby expansionl and contraction of chamber 225 will cause corresponding movement of disc 2| I The upper plate 220 is provided with a nipple 232 'which extends upwardly through 5 cap 2|5 and loosely engages the same so as to form a swivel connection-therebetween. The interior of the expansible chamber 225 is connected through nipple 232 with a tube 226 which comf municates with the interior of a bulb 221. This 10 bulb corresponds to the similar bulbs described in connection with the other embodiments of my invention. As ina preceding embodiment, 'the tube extends slightly'more than half-way into the bulb and isheld therein by a' perforated support- 15 ingmember 228. The upper portion of the bulb contains a substance 229 in vaporous condition and the remaining portion of the tube 226 and the interior of the chamber 225 are filled with a substance 23| which remains liquid throughout 20 the rangeof temperatures encountered during the use oi the apparatus, as inthe other forms of my invention. The refrigerant, inpassing through the valve, enters through aperture V|95 and passes there- 25 through into the screen |96 and from there into the main portion of the interior of the valve body. From there it passes between the-exterior of the valve guide 200 andthe interiorbf the cupshaped spring guide 205 between the ribs of the 30 i chamber 2|8 lis exposed to the outlet pressure so 35.

that upon the outlet pressure decreasing the plate 2|| is moved downwardly and upon the outlet pressure increasing the opposite action takes place. Thus, when the outlet pressure decreases due tothe compressor being put into operation, 4,) plate 2| is moved downwardly by spring 2|1 and moves the valve toward open position in opposh' tion to spring 206 and hence tends to increase the iiow of refrigerant so as to maintain the outlet pressure constant. 45

When there is an increase in the temperature adjacent the point'at which bulb 221 is located, which point will usually be in the vicinity of the loutlet of the evaporator, the vapor tension will increase and the increase in pressure caused 5' thereby will be transmitted to the interior of the ow of refrigerant to the evaporator. Since, 55

as in the preceding forms, no vaporizable substance is present in the control means except at the control bulb, the thermostatic control means will not be affected by the presence of a lower temperature in the vicinity of the valve than 60 at the control point, thus even though no means is provided for preventing frosting as in this species, an accurate thermostatic control isnevertheless ob'tained. Also, as in the preceding cases, the ow of refrigerant through the valve is controlled in such a manner as to tend to-maintain the pressure in the evaporator more orless constant.

` While I have shown and tailed embodiments rof my described certain deinvention, it will be 7'0 `understood that these are for purposes of illus- 1. In apparatus for cooling a space, pressure l actuated means for-varying the cooling eect of ,said apparatus, temperature responsive means for controlling said rst named means, said temperature responsive means comprising a vapor containing member located at a point remote from -said rst named means, the temperature adjacent said rst named means being lower than the temperature adjacent said v'apor containing vmember, `and. hydraulic means for transmitting a variation in /pressure in said vapor containing member due to a variation in vapor tension caused by a change in the temperature adjacent thereto t'o said pressure actuated means to cause the same to vary the cooling eiiect of said apparatus, said hydraulic transmitting means comprising a uid having vsuch characteristics that it remains in a liquid condition within the temperature range to which the apparatus is subjected, and having a low coeflicient of expansion;

rst mentioned means, the temperature adjacent said rst named meansbeing lower than. the temperature ,adjacent said vapor containing bulb, the portion of said bulb not occupied by said vapor and said conduit means being completely lled with a substance having such characteristics that it remains in the liquid state throughout the range of temperatures to which the same 1s subjected in use, said Asubstance serving as a hydraulic means for transmitting variations in pressure caused by variations in the vapor tension due to changes in the temperature adjacent the bulb to said` pressure actuated means to cause the same to vary the coolingv effect of said apparatus.

3. In. refrigerating apparatus, an expansion valve mechanism controlling the iiow of refrigerant, said valve mechanism comprising a valve seat, a valve, means urging 'said valve into engagem'ent with 'said seat, an expansible chamber having a movable wall, and means operatively associated with said movable wall and with s'ald valve to vary the extent to which said valve' is urged into engagement with said* seat, temperature responsive means for varying the operation of said valve mechanism, said means comprising a vapor containing bulb located at a pointmspaced from said valve mechanism and a conduit connecting said bulb with the interior of said expansible chamber, the temperature .within said-valve adjacent said chamber .tending to be lower than the temperature. adjacent said bulb, the portion'of the bulb not'occupied by said vapor, said conduit and said expansible chamber being lled with a substance having such characteristics that it remains in the liquid state throughout the range of temperatures to which it'is subjected in use, said substance serving as a hydraulic means for transmitting variations in pressure caused byA variations in the vapor tension in said bulb due to changes in the temperature adjacent thereto to said ex.

pansible chamber to vary thel extent to which the valve' is urged into engagement with the valve seat.

4. A thermostatically controlledl expansion valve mechanism for use in refrigerating appa. ratus comprising a valve body, a valve seat, a 5 valve movable into engagement therewith,l an inlet, for said valve, a passage for refrigerant extending from said Yinlet around said valve seat on all sides thereof an'd terminating at the valve seat, an expansible chamber in said valve body 10 having a movable wall, means operatively connectedA with said valve and with said wall for causing movement of said wall to effectihovement of said valve, a bulb adapted to be located at a point spaced fromsaid valve mechanism, l5 tubing connecting said bulb with said chamber, a vaporous substance in a portion of said bulb and a substance having such characteristics that it remains` in the liquid state throughout the range of temperatures encountered in the re- 20 frigerating apparatus with which the valve mechanism is to be employed, lling the portion of the bulb not occupied by said vapor, said tuband said expansible chamber.

5. A thermostatically controlled expansion 25 valve mechanism for use in I efrigerating apparatus comprising a valve body, a valve seat, a valve movable into engagement therewith, an

- inlet for said valve, a passage for refrigerant extending from said inletJ to said valve seat and 30 comprising 'an enlarged chamber extending around the valve seat on all sides thereof, an expansible chamber in said valve body having a movable wall, means operatively connected with said valve andwith said wall for causingmove- 35 ment of said wall to effect movement of'said valve, la bulb adapted to be located at apoint spaced from said valve mechanism, tubing connecting said bulbwith said chamber, a vaporous 'substance in a portion of said bulb and a sub- 40 stance having such characteristics that-it re-- mains in the liquid state throughout the range of temperatures encountered in the refrigerating apparatuswith which the valve mechanism is to be employed, llin'g the portion of the bulb 45 not occupied by said vapor, said tubing, and said expansible chamber.

- 6. A thermostatically controlled expansion valve mechanism for use in refrigerating apparatus comprising a -valve body, a valve seat, a 50 valve movable into engagement therewith, an inlet for said valve, a passage for refrigerant extending-from said inlet to said valve seat and comprising an annular passage closely surrounding -said valve seat, a second'l annular passage 55 above said seat in communication with said rst annular passage, and a third annular passage beneath said valve seatin communiction with said 'second annular passage and with said valve seat, an expansible chamber in said valve body I having a movable wall, means operatively connected with said valve `and with said wall for causing movement of Ysaid wall to eifect movement of said valve, a bulb adapted to be located in a space spaced from said valve mechanism, tubing connecting said bulb with said chamber, a-vaporous substance in a portion of said bulb and a substance having such characteristics that it remains in the liquid state throughout the range of temperatures encountered in the refrigeratng apparatus with which the valve mechnism is to be employed, filling the portion of'- the bulb not occupied by. said vapor, said tubing, and'said expansible chamber.

7. A thermostatically controlled -expansiun 15- l armena terminating at the valve seat, a passage of rela-y it remains in the liquid state throughout the range of'temperatures encountered in the refrigerating apparatus with which the valve mech'l anlsm is to be employed, filling the portion of the bulbnot occupied by said vapor, said tubing, and said expansible chamber.

8. An expansion valve mechanism comprising a'valve body, an inlet and an outlet in said valve body, a valve seat, a valve, a plurality .of 'opposed expansible and contractible chambers, each having a movable wall, means operatively associated with said movable wall and withsaid valve to cause movement of said valve upon expansion and contraction of said chambers, the contraction of one of said chambers causing a movement of the valve towards a closed position and the contraction yof thel other chamber causing a movement of thel valve towards an open position, and means for subjecting the movable walls of both of said chambers to the inlet pressure of the uid whose flow is controlled by said valve mechanism, and the movable wall of said first mentioned chamber having a larger effective s area than the movable wall of said second mentioned chamber so that upon an increase insaid inlet pressure, said valve will be moved towards a closed position so `as to maintain the flow of fluid constant in spite of said increase in inlet pressure. Y

9. An expansion valve mechanism comprising a valve body, an inlet and an outlet in said valve body, a valve seat, a valve, a plurality of opposed .expanslble and contractible chambers, each having a movable wall, means in said chambers yieldably urgingr the same towards expanded position and said movable walls in the direction of the valveseat, a member operatively associated with said valve and with said movable walls to maintainl said movable walls in av definitely spaced relationship in spite of said yieldable means, said member being so associated with said valvethat movement of said `member produces a corresponding movement 'of said valve, thecontraction of one of saidchambers causing movelment of said member so as to move said valve towards saidvalve seat, and means yfor subject-` ing the exterior of' both of said chambers to theinlet pressurel of the fluid whose flow is to be controlled, the effective area ofthe movable wall of the chamber whose contraction causes the valve to moveto closed position being larger than that of the movable wall of the other chamber so that upon an increase in said inlet pressure, said valve will be moved towards a 'closed position so as to maintain the ow of liquid con-- stant in -spite of said increase in inlet pressure. 10. An expansion valve mechanism comprising a valve body, an inlet and an outlet in said valve body, a valve` seat, a valve, a plurality of opposed expansible and contractible chambers,

. each having a movable wall, means operatively associated with said movable walls and with said valvebto cause movement of said valve upon expansion and contraction of said chambers, the

contraction of one of said chambers causing a movement of 'the valve towards a closed position and the contraction of the other chamber causing a movement of the'valve towards an open position, `means for subjecting the movable walls of both of said chambers to the inlet pressure of the fluid whose flow is controlled by said valve, and the movable wall of said first mentioned chamber having a larger effective area than the movable Wall of 4said second mentioned'chamber so that upon an increase in said inlet pressure, said valve will be moved towards a closed position soV as to maintain the flow of fluid constapt in spite of said increase in inlet pressure, and temperature responsive means for 4further controlling the position of said valve relative to said seat comprising a bulb containing a vaporous substance and means for connecting said bulb with theinterior of one of said chambers so that variation in the vapor tension in said bulb will act on the movable wall of said chamber to vary the position ofthe valve.

11. An expansion valve mechanism comprising a valve body, an inlet `and an outlety in said valve body, a valve seat, a valve, a plurality of opposed expansible and contractiblel chambers, each having a movable wall, means operatively associated with said movable walls and with said valve to cause movement of said -valve upon expansion and contraction of said chambers, the contraction of one of said chambershcausing a movement of the lvalve towards a closed position and the.

'Wall of said second mentioned chamber so that upon an increase in said inlet pressure, said valve will be moved towards a. closed position so as to maintain the flow of fluid constant in spite of said increase in inlet pressure, and temperature responsive means for further controlling Y a substance having such characteristics that it remains in the liquid state within the rangeof temperatures to which the same will be subjected in use in filling the said chamber, said conduit means and the portion of the bulb not occupied by the vapor.

12. In a refrigerating system. a'thermostatically controlled expansion `valve mechanism, comprising a valve seat, a valve, means for controlling the position of said valve with respectto the valve seat in accordance'with the inlet pressure of liquid refrigerant so as to compensate for variations in said inlet pressure, further `means for varying the position of said valve in accordance with the outlet pressure and tending to move said valve towards closed position upon an increase in said outlet pressure, and thermo- 'spaced from "said valve mechanism, said last named means comprising a` pressure responsive device for actuating the valve, and a bulb connected thereto and spaced from the valve mechanism, said bulb containing in partl a vaporous substance, the space in said bulb not occupied byA the vaporous substance, and the pressure responsive device, being completely liilled with a iiuid having such characteristics that it remains in the liquid state throughout the temperature range to which it is subjected.

13. An expansion valve mechanism comprising a valve b ody, an inlet and an outlet in said valve body, a valve seat, a valve, a plurality of opposed expansible and contractible chambers, each having a movable wall, means operatively associated with said movable walls and with said valve to cause movement of said valve upon expansion and contraction of said chambers the contraction of one of said chambers causing a movement of the valve towards a closed position and the contraction of the other chamber causing a-movement of the -valve towards an open position, means for subjecting the movable walls of both of said chambers to the'inlet`- pressure of the fluid whose iiow is controlled by said valve and the movable wall of said iirst mentionedchamber havinga larger effective area than the movable wall of said second mentioned chamber so that upon an increase in said inlet pressure, said valve will be moved towards a closed position so as to maintain the ow of iiuid constant in spite of said increase in inlet pressure, and means subjecting the interior of the second chamber to a pressure corresponding to-the outlet pressure so as to move the valve towards an open position upon a decrease in said outlet pressure so asto maintain. said outlet pressure constant.

14. In a thermostatically controlled expansion valve mechanism, a valve body'having inlet and4 outlet openings, a plurality of opposed expansble chambers, having movable walls opposed to each other,` a valve seat and a valve located in said valve body between s'aid two movable walls, a. member holding said walls in spaced relation to prevent relative movement thereof, said member being associated with said. valve`so as to cause movement of said valve upon movement of said member so that upon expansion of one of said chambers andthe contraction of the other of said chambers said valve is moved towards an open position and upon the opposite movement of said chambers taking place, said valve is moved towards "a closed position, the interior of the first mentioned of raid chambers being hydraulically connected with a vapor-containing bulb so that upon an increase in the vapor tension in said bulb due to an increase in temperature adjacent said bulb said valve will be moved towards valved, the movable wall oi the first mentioned n open position, and the interior of' the otherl oi' said chambers being subjected to the outlet pressure of the fluid being valved, so that upon an increase in the outlet pressure. said valve will be moved toward a closed position sc as to tend to maintain said outlet pressure constant, and

means to subject the exterior of bth of said chambers to the inlet pressure of the fluid being of said chambersqhaving a larger diameter than the movable wall of the other of said chambers 4so that upon an increase in inlet pressure said valve will be 4moved to a closed position so as to' tend to maintain the flow of fluid throughsaid valve constant. Y

A15. In an expansion valve mechanism, a valve bodyincluding a passage having a valve port therein,4 an inlet conduit communicating with I `one side of the valve port, an outlet conduit intersecting said passage at the other side of the valve port, a diaphragm chamber into which 'saidk passage opens, a diaphragm in said chamber, a

therein, an inlet conduit communicating with one side of the valve port, an outlet conduit intersecting said passage at the other side of the valve port, a diaphragm chamber into which said passage opens, a diaphragm in said chamber, a valve` cooperating with the valve port, and a valve plunger for movingsaid valve in response to movements of said diaphragm. said plunger completely filling the passage for a. portion of its length to prevent ilow of fluid being valved into said diaphragmchamber and, being of reduced dimensions for another portion of its length to permit ilow of said fluid to said outlet passage, the zone of transition in dimensions of said plunger being recessed 17. In an expansion valve mechanism for re frigeraticn systems, in combination, a valve casing, valve means in said casing-for reducing the pressure of refrigerant flowing therethrough, said valve means comprising a valve port and a cooperating valve member, temperature responsive means for adjusting said valve means, said temperature responsive means comprising an actuating device for said valve means, a temperaturev responsive bulb, and means connecting said bulb to said actuating device, said bulb containing a ,vaporcus substance for exerting diierent vapor` pressures for different temperatures to which said bulb is subjected, said connecting means includ- V ing a hydraulic pressure transmitting fluid having suchcharacteristics that it remains in the liquid state within the temperature range to which said expansion valve mechanism is subjected.

18. In an expansion valve mechanism for refrigeration systems, in combination, a valve casing, a valve means in said casing for reducing thel pressure of refrigerant flowing therethrough, said valve means comprising a valve port and a cooperating valve member, and means for adjusting said valve means in a manner to compensate for variations in inlet pressure on said valve means sc as t'o maintain a substantially constant flow of uid through said valve means regard- ,less of changes in inlet pressure, said adjusting means comprising a pressure responsive device responsive to inlet pressure and arranged to adjust said valve means in a manner to varyA the valve opening :lust suiilciently to counteract a variation in ow through the valve due to a change in inlet pressln'e.

19. In an expansion valve mechanism for refrigeration systems, in combination, a valve casing, a valve means in' said casing for reducing.

the pressure of refrigerant flowing therethrough, said valve' means comprising a valve port cooperating valve member,- means responsive to theoutletpressure of said valve means for conand a trolling said valve means in a manner to decrease the valve opening upon increase -in outlet pressure, and means for adjusting said valve means in` a manner to compensate for variations in inlet pressure on said Valve means so as to maintain a substantially constant ow of iluid through said valve means regardless of changes in inlet pressure, said adjusting means comprising a pressure responsive device responsive to inlet pressure and arranged to adjust said valve means in a manner to vary the valve opening just sufficiently to counteract a variation in flow through the valve due to achange in inlet pres-` sure.

20. In an expansion valve' mechanism for refrigeration systems, in combination, a valve casing, a valve means in said casing for reducing the pressure of refrigerant flowing therethrough,

' said valve means comprising a valve port and a cooperating valve member, temperature responsive means for positioning said valve means, and

` means for adjusting said valve means in a manner to compensate for variations in inlet pressure-A on said valve meansso as to maintain a 'substantially constant flow of iiuid through said valve means regardless of changes in inlet pressure.

said adjusting means comprising a pressure responsive device responsive to inlet pressure and arranged to adjust said lvalve means in a manner yeratively connected.'

placing said inlet and outlet chambers in communication, a valve member cooperating with said valve port for controlling the ow of said liquidrefrigerant from said inlet chamber to said outlet chamber, and a diaphragm structure subjected to the liquid refrigerant onV the inlet side of the valve for positioning said valve member, said diaphragm structure being formed to provide two separate be subjected tothe pressure of the low pressure refrigerant and arranged in a manner tending to urge said valve member towards ow vrestricting position upon an increase in pressure of Isaid low pressure refrigerant, and said other diaphragm chamber being subjected to a pressure varying with the temperature at a thermostatic device towhich said last mentioned chamber is op- PAUL F. smvERs.

diaphragm chambers, one of'said diaphragm chambers being arranged to

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