Thermostatic expansion valves including interchangeable metering pins
A thermostatic expansion valve includes an operating rod, a recessed receiver portion, and a first metering pin positioned at least partially within the receiver portion to selectively contact the operating rod. The first metering pin includes a base diameter, an overall length, and a taper portion. The taper portion is tapered at a specified degree relative to a longitudinal axis of the first metering pin. The thermostatic expansion valve is adapted to operate at a first specified refrigeration tonnage when the first metering pin is positioned at least partially within the receiver portion, and to operate at a second specified refrigeration tonnage when the first metering pin is replaced with a second metering pin including a different taper portion than the first metering pin.
1. A thermostatic expansion valve comprising:
an operating rod;
a receiver portion;
a first metering pin positioned at least partially within the receiver portion to selectively contact the operating rod, the first metering pin including a base diameter, an overall length, and a taper portion, the taper portion tapered at a specified degree relative to a longitudinal axis of the first metering pin;
wherein the thermostatic expansion valve is adapted to operate at a first specified refrigeration tonnage when the first metering pin is positioned at least partially within the receiver portion, and to operate at a second specified refrigeration tonnage when the first metering pin is replaced with a second metering pin including a different taper portion than the first metering pin;
wherein:
the base diameter, overall length, and specified degree of the taper portion relative to the longitudinal axis of the first metering pin facilitate a balanced port where an inlet pressure times an area of the taper portion of the first metering pin results in an upward closing force that is balanced with a downward force according to a pressure differential across the first metering pin; and
a base diameter, an overall length, and a specified degree of the taper portion relative to a longitudinal axis of the second metering pin facilitate a balanced port where the inlet pressure times an area of the taper portion of the second metering pin results in the upward closing force that is balanced with the downward force according to the pressure differential across the second metering pin.
2. The thermostatic expansion valve of claim 1 , further comprising at least one of a common seal, a common push rod, a common spring carrier, a common buffer plate, and a common spring, wherein the first metering pin is replaceable by the second metering pin without changing said at least one of the common seal, the common spring carrier, the common buffer plate, and the common spring.
3. The thermostatic expansion valve of claim 1 , wherein the first metering pin is adapted to facilitate operation of the thermostatic expansion valve with at least one of a minimum tonnage of 1/10 Ton for R-290 system refrigerant, and a minimum tonnage of 1/14 Ton for R-404A or R-1234yf system refrigerants.
4. The thermostatic expansion valve of claim 1 , further comprising a check valve.
5. The thermostatic expansion valve of claim 1 , wherein the thermostatic expansion valve comprises a hermetic thermostatic expansion valve.
6. The thermostatic expansion valve of claim 1 , wherein at least one of the operating rod, the receiver portion, and the first metering pin comprises stainless steel.
7. The thermostatic expansion valve of claim 1 , further comprising an inlet port for receiving refrigerant and an outlet port for supplying refrigerant, the metering pin located in a refrigerant flow path between the inlet port and the outlet port.
8. A refrigeration system including the thermostatic expansion valve of claim 1 , wherein the refrigeration system comprises at least one of a free-standing refrigerator, a milk cooler, a food service preparation table, a refrigerated drawer, an under-counter refrigerator, a walk-in refrigerator, and a roll-in refrigerator.
9. A cooling system including the thermostatic expansion valve of claim 1 , wherein the cooling system comprises at least one of ice production equipment, ice storage equipment, a freezer, a storage cooler, a soft serve ice cream machine, a compressor, a condenser, an evaporator, a water filter, a slush and/or smoothie machine, a blast chiller, a blast freezer, a drop-in pan chiller, an ice cream cabinet, an air conditioner, and a heat pump.
10. A thermostatic expansion valve comprising:
an operating rod;
a receiver portion;
a first metering pin positioned at least partially within the receiver portion to selectively contact the operating rod, the first metering pin including a base diameter, an overall length, and a taper portion, the taper portion tapered at a specified degree relative to a longitudinal axis of the first metering pin;
wherein the thermostatic expansion valve is adapted to operate at a first specified refrigeration tonnage when the first metering pin is positioned at least partially within the receiver portion, and to operate at a second specified refrigeration tonnage when the first metering pin is replaced with a second metering pin including a different taper portion than the first metering pin;
wherein the thermostatic expansion valve is adapted to operate at a third specified refrigeration tonnage when the first metering pin or the second metering pin is replaced with a third metering pin including a different taper portion than the first metering pin and the second metering pin.
11. The thermostatic expansion valve of claim 10 , wherein:
the base diameter, overall length, and specified degree of the taper portion relative to the longitudinal axis of the first metering pin facilitate a balanced port where an inlet pressure times an area of the taper portion of the first metering pin results in an upward closing force that is balanced with a downward force according to a pressure differential across the first metering pin; and
a base diameter, an overall length, and a specified degree of the taper portion relative to a longitudinal axis of the second metering pin facilitate a balanced port where the inlet pressure times an area of the taper portion of the second metering pin results in the upward closing force that is balanced with the downward force according to the pressure differential across the second metering pin.
12. The thermostatic expansion valve of claim 10 , wherein:
the first metering pin comprises a ⅕ ton metering pin when the thermostatic expansion valve is operated with a specified refrigerant;
the second metering pin comprises a ¼ ton metering pin when the thermostatic expansion valve is operated with the specified refrigerant; and
the third metering pin comprises a ½ ton metering pin when the thermostatic expansion valve is operated with the specified refrigerant.
13. The thermostatic expansion valve of claim 10 , further comprising at least one of a common seal, a common push rod, a common spring carrier, a common buffer plate, and a common spring, wherein the first metering pin is replaceable by the second or third metering pin without changing said at least one of the common seal, the common spring carrier, the common buffer plate, and the common spring.
14. The thermostatic expansion valve of claim 10 ,
wherein a normal projection area of the first metering pin on the operating rod at a tapered end of the first metering pin is equal to an exposed area of the operating rod to balance the effects of pressure on the thermostatic expansion valve when the first metering pin is positioned at least partially within the receiver portion.
15. The thermostatic expansion valve of claim 14 , wherein the base diameter, overall length, and specified degree of the taper portion relative to the longitudinal axis of the first metering pin facilitate a balanced port where an inlet pressure times an area of the taper portion of the first metering pin results in an upward closing force that is balanced with a downward force according to a pressure differential across the first metering pin.
16. A method of replacing a metering pin in a thermostatic expansion valve, the thermostatic expansion valve including an operating rod and a receiver portion, the method comprising:
inserting a first metering pin at least partially within the receiver portion to selectively contact the operating rod to operate the thermostatic expansion valve at a first specified refrigeration tonnage, the first metering pin including a base diameter, an overall length, and a taper portion, the taper portion tapered at a specified degree relative to a longitudinal axis of the first metering pin;
removing the first metering pin from the receiver portion; and
inserting a second metering pin at least partially within the receiver portion to selectively contact the operating rod to operate the thermostatic valve at a second specified refrigeration tonnage, wherein the second metering pin includes a different taper portion than the first metering pin;
wherein:
the base diameter, overall length, and specified degree of the taper portion relative to the longitudinal axis of the first metering pin facilitate a balanced port where an inlet pressure times an area of the taper portion of the first metering pin results in an upward closing force that is balanced with a downward force according to a pressure differential across the first metering pin; and
a base diameter, an overall length, and a specified degree of the taper portion relative to a longitudinal axis of the second metering pin facilitate a balanced port where the inlet pressure times an area of the taper portion of the second metering pin results in the upward closing force that is balanced with the downward force according to the pressure differential across the second metering pin.
17. The method of claim 16 , wherein:
the thermostatic expansion valve further includes at least one of a common seal, a common push rod, a common spring carrier, a common buffer plate, and a common spring; and
removing the first metering pin and inserting the second metering pin includes removing the first metering pin and inserting the second metering pin without changing said at least one of the common seal, the common spring carrier, the common buffer plate, and the common spring.
18. A method of replacing a metering pin in a thermostatic expansion valve, the thermostatic expansion valve including an operating rod and a receiver portion, the method comprising:
providing a first metering pin that is positionable at least partially within the receiver portion to selectively contact the operating rod to operate the thermostatic expansion valve at a first specified refrigeration tonnage, the first metering pin including a base diameter, an overall length, and a taper portion, the taper portion tapered at a specified degree relative to a longitudinal axis of the first metering pin;
providing a second metering pin that is positionable at least partially within the receiver portion to selectively contact the operating rod to operate the thermostatic valve at a second specified refrigeration tonnage when the first metering pin is replaced with the second metering pin, wherein the second metering pin includes a different taper portion than the first metering pin; and
providing a third metering pin that is positionable at least partially within the receiver portion to selectively contact the operating rod to operate the thermostatic valve at a third specified refrigeration tonnage when the first metering pin or the second metering pin is replaced with the third metering pin, wherein the third metering pin includes a different taper portion than the first metering pin and the second metering pin.
19. The method of claim 18 , wherein:
the base diameter, overall length, and specified degree of the taper portion relative to the longitudinal axis of the first metering pin facilitate a balanced port where an inlet pressure times an area of the taper portion of the first metering pin results in an upward closing force that is balanced with a downward force according to a pressure differential across the first metering pin; and
a base diameter, an overall length, and a specified degree of the taper portion relative to a longitudinal axis of the second metering pin facilitate a balanced port where the inlet pressure times an area of the taper portion of the second metering pin results in the upward closing force that is balanced with the downward force according to the pressure differential across the second metering pin.
20. The method of claim 18 , wherein the first metering pin, the second metering pin and the third metering pin are each adapted to operate at different refrigeration tonnages, and wherein:
the first metering pin comprises a first one of a ½ ton, ⅓ ton, ¼ ton, ⅕ ton and 1/7 ton metering pin, when the thermostatic expansion valve is operated with a specified refrigerant;
the second metering pin comprises a different second one of a ½ ton, ⅓ ton, ¼ ton, ⅕ ton and 1/7 ton metering pin, when the thermostatic expansion valve is operated with the specified refrigerant; and
the third metering pin comprises a further different third one of a ½ ton, ⅓ ton, ¼ ton, ⅕ ton and 1/7 ton metering pin, when the thermostatic expansion valve is operated with the specified refrigerant.