Pilot operated automatic expansion valve

Claim 2

A low-differential high-capacity expansion valve for controlling the flow of refrigerant from the high-pressure portions to the low-pressure portions of refrigerating systems for maintaining a substantially constant low-pressure in the lowpressure portions including a housing having an inlet adapted to be connected to said high-pressure portions, and an outlet adapted to be connected to said low-pressure portions, wherein the improvement comprises an evacuated enclosure provided with a flexible diaphragm means, said housing being provided with a chamber connected to said low-pressure portions coNtaining said evacuated enclosure and diaphragm means, said housing being provided with a piston chamber containing a slidable piston valve having a high maximum rate of flow connected between said inlet and said outlet and provided with a piston extending into said piston chamber, said housing having a passage extending from the said high-pressure portions to said piston chamber, and a pilot valve connected in series with said passage and operably connected to said flexible diaphragm means for controlling the flow to said piston to select the position of said piston valve in accordance with the pressure of said low-pressure portion.

Claim 3

Refrigerating apparatus including evaporating means having an inlet and an outlet, a tubular housing connected to said inlet and said outlet and extending from said outlet to said inlet, said housing having an outlet passage for evaporated refrigerant connected to said outlet and having an entrance for liquid refrigerant adjacent to but separated from said outlet passage and an inlet passage extending from said entrance to said inlet of said evaporating means, said housing being provided with a valve housing adjacent said inlet containing an enclosure and a piston chamber, said enclosure containing an evacuated sealed casing comprising a flexible diaphragm means, a piston valve in said piston chamber containing valve slots, said valve housing having valve slots in the walls of said piston chamber with which the valve slots in the piston are adapted to align in predetermined positions of the piston for maximum flow of refrigerant from said inlet passage to said inlet, said valve housing having pilot valve passage means extending from said inlet passage to said piston chamber, pilot valve means in said pilot valve passage, said flexible diaphragm means having operating means for operating said pilot valve in accordance with the pressure in said enclosure in the valve housing, and means forming a control passage extending from said outlet passage through said housing to said enclosure for operating said flexible diaphragm means in response to the pressure conditions in said outlet passage for controlling the position of said piston valve and the registering of its slots with the slots in the valve housing.

Claim 4

Refrigerating apparatus including evaporating means having an inlet and an outlet, a tubular housing connected to said inlet and said outlet and extending from said outlet to said inlet, said housing having an outlet passage for evaporated refrigerant connected to said outlet and having an entrance for liquid refrigerant adjacent to but separated from said outlet passage and an inlet passage extending from said entrance to said inlet of said evaporating means, said housing being provided with a valve housing adjacent said inlet containing an enclosure and a piston chamber, said enclosure containing an evacuated sealed casing comprising a flexible diaphragm means, a piston valve in said piston chamber containing valve slots, said valve housing having valve slots in the walls of said piston chamber with which the valve slots in the piston are adapted to align in predetermined positions of the piston for maximum flow of refrigerant from said inlet passage to said inlet, said valve housing having pilot valve passage means extending from said inlet passage to said piston chamber, pilot valve means in said pilot valve passage, said flexible diaphragm means having operating means for operating said pilot valve in accordance with the pressure in said enclosure in the valve housing, and means forming a control passage extending from said outlet passage through said housing to said enclosure for operating said flexible diaphragm means in response to the pressure conditions in said outlet passage for controlling the position of said piston valve and the registering of its slots with the slots in the valve housing.

Claim 5

Refrigerating apparatus as defined in claim 2 in which said housing is provided with an access opening and a removable closure for said access opening which are coaxially aligned with the evacuated sealed casing and said flexible diaphragm means and said control passage, said valve housing being provided with adjusting means in alignment with said control passage for adjusting the location of said evacuated sealed casing, said control passage and said access opening being large enough to receive a tool for operating said adjusting means.

Claim 6

Refrigerating apparatus as defined in claim 2 in which filtering material surrounds the valve housing adjacent the valve slots therein.

Claim 7

A low-differential high-capacity expansion valve for controlling the flow of refrigerant from the high-pressure portions to the low-pressure portions of refrigerating systems for maintaining a substantially constant low-pressure in the low-pressure portions including a housing having an inlet adapted to be connected to said high-pressure portions and an outlet adapted to be connected to said low-pressure portions, means forming within said housing a diaphragm chamber provided with diaphragm means adapted to be exposed to the pressure within said low-pressure portions, a main valve of large maximum flow capacity located between said inlet and said outlet in said housing, a fluid motor for operating and selecting the position of said main valve to control the flow from said inlet to said outlet, said housing having passage means extending from said inlet to said fluid motor, and a pilot valve operated by said diaphragm means located in series with said passage means for controlling the flow to said fluid motor to select the position of said main valve in accOrdance with the pressure of said low-pressure portions.

Claim 8

A low-differential high-capacity expansion valve for controlling the flow of refrigerant from the high-pressure portions to the low-pressure portions of refrigerating systems for maintaining a substantially constant low-pressure in the low-pressure portions including a housing having an inlet adapted to be connected to said high-pressure portions and an outlet adapted to be connected to said low-pressure portions, means forming within said housing a diaphragm chamber provided with diaphragm means adapted to be exposed to the pressure within said low-pressure portions, a main valve of large maximum flow capacity located between said inlet and said outlet in said housing, a fluid motor for operating and selecting the position of said main valve to control the flow from said inlet to said outlet, said housing having passage means extending from said inlet to said fluid motor, and a pilot valve operated by said diaphragm means located in series with said passage means for controlling the flow to said fluid motor to select the position of said main valve in accOrdance with the pressure of said low-pressure portions.