US1769859A - Expansion valve - Google Patents

Description

July 1, 1930.

L. C. ROBERTS EXPANS ON VALVE 2 sheets sheet 1 Filed Jan. 19, 1927 lNVENTOR L. C. FUEL-7W6 WITNESS July 1, 1930. L. c. ROBERTS 7 1,769,859

EXPANS ION VALVE Filed Jan. 19, 1927 2 Sheets-Sheet 2 2 6 O. I

Z6 y Y ZZ x wnwzss L.a/$JZ$$% Patented July l, 193% entree stares iseasse eATENr creme rnaoy'oun'ronnonners, or FARMINGTON, connncrrour, essrenoa 'ro THE Auro- MATIC REFRIGERATING conrranv, or rrnn rroan, oonnnorrccr, A CORPORATION OF NEW" JERSEY EXPANSION VALVE Application filed January 19, 1927. Serial No. 162,077.

My invention relates more especially to expansion valves suitable for refrigerating systems. 7

' There has been .some recent development in expansion valves to obtain one which would be less seriously afltectedby the high velocity of the liquid passing the expansion point than the valves ordinarily used. This has resulted in Combining two valves to divide the pressure drop existing so that the velocity past the expansion points is divided into two stages, thev primary stage employing a pressure range of about 180 lbs, from condenser pressure down to about 60 lbs. The secondary stage works through a pressure range of about 60 lbs, to the pressure in the expansion coils-usually about 15 to lbs. Such a combination, has valves using two diaphragms, each diaphragm regulating a valve which is actuated by the desired pressure for the two-stage expansion.

The object of the present invention is to provide means of improved constructionfor regulating the operation of expansion valves under the control of thermostatic devices located in the refrigerated chamber, so that when the room is cooled to a predetermined temperature, the thermostatic devices will 'relieve'the tension on the ex pansion valve in such a way as to permit it to close and act asa stop valve.

In its preferred embodiment, my invention contemplates a diaphragm exposed on one side to the pressure fluid on the low pressure side of theexpansion valve which is permitted to close whenever there is a suificient rise of the pressure acting against the diaphragm. Acting against the other side of said diaphragm is a variable pressure medium preferably in the form of a spring,-the tension in said spring being changeable under the action of electromagnetically operated means under the control of a thermostat in such a way that whenever the temperature in the refrigerated chamber rises above apredeterminedmaximum, the load on said diaphragm is increased sufficiently to open the expansion valve and whenever the temperature falls below a predetermined minimum, said load is reduced sufficiently to permit said valve to close. g

Further details of the invention will appear in the description and by reference to the accompanying drawing in which:

Fig. l is a schematic view of a two chamber refrigerating plant showing the manner of applying the invention. I f Fig. 2 is a sectional view of the combination valve.

Fig. 3 is a sectional view showing a n1odified form of valve.

Referring first to Figure 1-, a compressor 1 is shown driven by an electric motor 2, current to which is "supplied from mains 3 and starting switch 4:. At 5 is shown a switch which is operated by a back pressure device 6 that operates to start the motor when the back pressure from the refrigerating coils rises to a predetermined point.

At 7 and 8 are shown two refrigerating coils and adjacent to each coil is shown at 9 and 1O electric thermostats that operate to close the circuit from supply conductors 3 to leads l1 and 12 that are'connected to solenoid coils 13 and 14. The expansion valve shown at 15 in Fig. 1 is illustrated in section 011 an enlarged scale in Fig. 2.

The valve body 15 is provided with an intermediate chamber 16 separated from the high pressure pipe 17 by valve 18 and from the low pressure pipe 12 by valve 20. These valves are shown with springs 21 and 22 for pressing them to their seats. A diaphragm 23 bears against the low pressure side of valve 18 and closes an opening to the atmosphere from the intermediate chamber 16. The pressure in chamber 16 therefore tends to press the diaphragm away from th e valve and thereby allow the spring 21 to seat the valve. The high pressure in pipe 17 also tends to close the valve. Opposed tothese valveclosing tendencies is a spring 24 which through a stem 25 maybe compressed by a lever 26 pivoted at one end I to a; fixed member 27, and at its free end to a connecting rod 28 on the end of which is a core 29 of the electric solenoid 13. At 30 shown avdiaphragm controllnig the secondary expansion valve 20. A spring 31,;as

shown in Fig. 3 under adjustment of screw 32, may be used to apply a predetermined pressure that will allow the valve to open only when the low ressure in the refrigerating coils falls below a predetermined In Fig. 2 a construction is shownmhere tlw secondary valve 20 has the outside surface of-its diaphragm placed under the influence of pressure sensitive to the temperature of the refrigerating room. ehaaiiben overthe diaphragm '30 is connected by pipe 33 with a pipe 34 enveloping the last pipe of the refri crating coils. The

'pe 3471s filled with a uid under pressure,

or example, an isolated volume of ammonia dawn from the high pressure system. when the li uid ammonia or other refriger- It reaches the last pipe of the refrigerating coils, thetemperature of the fluid in the enveloping casing 34 will be lowered and will wntl'aet suflieiently to relieve the pressure on theupper. side of the dia hragm so that the valve 20 can close an act as a stop veins, The vm nds y a e n e not be thermostatically controlled. It may be a expansion valve as shown in Figure 3, or in some cases a hand operated expansion zslve which simply employs a hand, adpzst- It, is to be observed that the valve are free of stuffing oxes h hei a endant leakages n irieti n,

. Ln operation, when the rooms are cooled to a predetermined temperature, the ther- 9 andlO will shut off current from tho eolenoids 13 and 14;, thus releasing the sparing tension above, the primary dia- 9 ram. This release of pressure causes Cg: .sr'imary valve to close and interrupts t ow of refrigerant. into the expansion This in turn produces a drop. in the pressure, which may be used to stop 3 operation of the compressor by the usual back pressure control. When the room tem-. rises to the starting point of the i ostat, current is imposed upon the sole nerd, which in turn produces a spring tension uponthe primary diaphragm, which opens the ,valve, admitting refrigerant and starts compressor through the rise in back ewe V r the mnnmg period of the comthe pressure underneath the primary iaphragin is the intermediate pressure referred to. as being approximately 1km, this. pressure being maintained constautaccording to the tension on the diaphragm, as in the usual diaphragm operatq ed valves. action of the solenoid is to bring an force, that is responsive to the room 'mpprature, to make the primary valve an ion valve when the room temperature is'abowe the. predetermined point and then the prorper temperature is reached to allow the valve to seat positively and act as a stop valve. When acting as an expansion valve it divides with the secondary valve the work of reducing the pressure and thereby saves considerably the wear due to the rapid flow of fluid. When acting as a stop valve the wear is eliminated altogether.

I olaimz 1. In a fluid pressure expansion valve, the combination of a valve-body, a high-pres- A sure ipe, a low-pressure pipe, an intermediate 0 amber, an expansion valve interposed between said high-pressure pipe and said intermediate chamber, a second expansion valve interposed between said intermediate chamber and said low-pressure pipe, a movable diaphragm operating on each of said e pansi n a ves in a irection tending t open said expansion valve, means for variably loading the diaphragm corresponding to the second-mentioned expansion valve in opposition to the pressure on the 10mmsure side thereof, and thermostatieallyeontrolled means for applying difierent con. stant pre sures f predetermin d magui tudes to the d aphragm corresponding to the first-mentio d expansion al e on the side Qpposite, to. that ex d to the pressure in said intermediate 0 amber.

2. In a fluid-pressure expansion valve, the combination of a valve body provided with a high-pressu e inlet, a lo pressure outlet and an intermediate pressure chamber, an expansion valve interposed between said high-pressure inlet and said intermediate pressure chamber, a diaphragm operating on said expansion valve, said diaphragm hei exposed on one side to the pressure in sai intermediate pressure chamber, a compres sion spring operative on the other side of said diaphragm in opposition to the. pressure in said intermediate pressure chamber, a sec nd expansi n a e i rp sed tw en said intermediate pressure chamber and said low-preassure outlet, the last1mentioned ex pansion valve being adapted in cooperation with the first-mentioned expansion valve to maintain a substantially constant predetermined pressure in said intermediate pressure chamber, and thermostaticall3l-0outrolled means for compressing and relaxin saidcompression spring for applying di ferent fixed pressures in alternation to the first-mentioned expansion valve whereby it is adapted to operate asv an expansion value when the temperature is above a predetermmed point and to operate as a stop valve when e emp r re is elow said predetermined point,

3. In a fluid pressure valve, the combines tion of a valve body prov ded with high pressure inlet and low-pressure outlet, and an intermediate pressure chamber, an ex,- panslon valve interposed between said highpressure inlet and said intermediate pressure chamber, a. second expansion valve posed between said intermediate pressure chamber and said low-pressure outlet, a diaphragm operative upon each of said expansion valves, each of said diaphragms being exposed on one side to the pressure of the pressure fluid on the low-pressure side of the expansion valve, variable pressure means operative upon the otherside of the diaphragm operating on the second-mentioned expansion valve, a compression spring operating on the other side of the diaphragm operating on the first-mentioned expansion valve, and thermostatically-controlled means for imparting a predetermined amount of compression to said compression spring, the first-mentioned expansion valve with its spring under compression and the secondmentioned expansion valve under its variable loading, being adapted to maintain a predetermined substantially constant pressure in the intermediate pressure chamber, said first-mentioned expansion valve being adapted when said compression spring is relaxed, to perform the functions of a stop valve.

l. In a fluid pressure expansion valve, the combination of a valve-body provided with a high-pressure valve-chamber, a diaphragm chamber having a diaphragm forming a movable wall thereof, and a valve-port opening extending between said chambers, an expansion valve for said valve-port opening, said expansion valve being provided with a reduced stem extending through said valve-port opening and into engagement with said diaphragm, said valve body being provided with a second valve-chamber in open communication with said diaphragm chamber, a second diaphragm chamber hav- 40 ing a diaphragm forming a movable wall thereof, and a valve-port opening between said second valve-chamber and said second diaphragm chamber, a second expansion valve for the last-mentioned port-opening, said second expansion valve having a reduced stem in engagement with the last mentioned diaphragm, thermostatically controlled means for variably loading the lastmentioned diaphragm, and thermostaticallycontrolled means for applying dilierent predetermined fixed loads to the first-mentioned diaphragm.

LEROY CLINTON ROBERTS.

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