Thermo bulb for use with the thermostatic expansion valve

• US 5,044,551 A
• Filed: 12/29/1989
• Issued: 09/03/1991
• Est. Priority Date: 01/08/1988
• Status: Expired due to Term

• Current Assignee: Fuji Filter Manufacturing Co., Ltd.
• Original Assignee: Fuji KOKI Manufacturing Company Limited
• Inventors: Watanabe, Kazuhiko, Tanaka, Hazime
• Primary Examiner(s): Tapolcai, William E.
• Application Number:
  US07/462,299
• Time in Patent Office: 613 Days
• Field of Search: 62/225, 236/92 B, 236/99 R, 374/202, 126/400
• US Class Current: 236/92.00B
• CPC Class Codes: F25B 2341/0682 the sensor contains sorbent materials
• CPC Class Codes: F25B 2600/21 Refrigerant outlet evaporator temperature
• CPC Class Codes: F25B 41/335 via diaphragms
• CPC Class Codes: G01K 5/326 using a fluid container connected to the deformable body by means of a capillary tube

Abstract

A thermo bulb for use with a thermostatic expansion valve, includes a temperature sensing cylinder connected to a power element of a valve unit of the thermostatic expansion valve, a thermal ballast arranged in the temperature sensing cylinder and made by a ceramic sinter which has silica and alumina as its main components, an operating fluid sealed in the temperature sensing cylinder to change from gas to liquid and vice versa response to temperature sensed by the cylinder at an outlet of an evaporator of a refrigeration system, and an arrangement for fixing the thermal ballast into a certain position in the temperature sensing cylinder so as not to prevent the thermal ballast from making contact with an inner surface of the temperature sensing cylinder.

Claims

1. A thermo bulb for use with a thermostatic expansion valve, comprising:

a temperature sensing cylinder having an inner surface and being connected to a power element of a valve unit of the thermostatic expansion valve;

a thermal ballast arranged in the temperature sensing cylinder and made by a ceramic sinter, which includes silica and alumina as its main components so as to have at least one bore hole extending straight through in an axial direction of the temperature sensing cylinder and opening at both axial ends of the thermal ballast;

an operating fluid, sealed in the temperature sensing cylinder so as to change from a gas phase to a liquid phase and vice versa, in response to temperature sensed by the temperature sensing cylinder at an outlet of an evaporator of a refrigeration system; and

means for fixing the thermal ballast into a certain position with substantially unequal axial clearances in the temperature sensing cylinder so as not to prevent the operating fluid in the gas phase from making surface contact with the inner surface of the temperature sensing cylinder;

whereby the thermal ballast is able to trap and hold the operating fluid in the liquid phase at surfaces and pores of the thermal ballast.

2. The thermo bulb for use with the thermostatic expansion valve according to claim 1, wherein a plurality of pores in the thermal ballast occupy about 20% to about 40% of the whole volume of the thermal ballast.

3. The thermo bulb for use with the thermostatic expansion valve according to claim 1, wherein the weight percentage of alumina and silica which are the main components of the ceramic sinter for the thermal ballast is in a range of 1:

about 0.17 to 1;

about 0.2.

4. The thermo bulb for use with the thermostatic expansion valve according to claim 1, wherein the thermal ballast is shaped like a hollow cylinder and the temperature sensing cylinder has an axially extending gas injection through hole at a position that substantially corresponds to a through hole of the hollow cylinder-shaped thermal ballast.

5. The thermo bulb for use with the thermostatic expansion valve according to claim 1, wherein the thermal ballast has at least two through holes extending in an axial direction thereof and said through holes function as the bore hole extending straight through the thermal ballast.

6. The thermo bulb for use with the thermostatic expansion valve according to claim 1, wherein the thermal ballast has a polygonal cross-section that has a plurality of grooves extending on an outer surface of the thermal ballast in an axial direction so as to function as the bore hole extending straight through the thermal ballast.

7. The thermo bulb for use with the thermostatic expansion valve according to claim 1, wherein the thermal ballast has at least two grooves formed on an outer surface so as to extend in an axial direction thereof and said grooves function as the bore hole extending straight through the thermal ballast.

8. The thermo bulb for use with the thermostatic expansion valve according to claim 1, wherein a gas, which is not condensed in a range of temperature sensed by the cylinder at the outlet of the evaporator of the refrigeration system, is sealed in said temperature sensing cylinder to produce a pre-pressure.

9. The thermo bulb for use with the thermostatic expansion valve according to claim 1, wherein the fixing means include a pair of net-like members that sandwich the thermal ballast at both axial ends in order to fix the thermal ballast into said certain position with a large space at an upper end in the temperature sensing cylinder.

10. A thermo bulb for use with a thermostatic expansion valve, comprising:

a temperature sensing cylinder having an inner surface and being connected to a power element of a valve unit of the thermostatic expansion valve;

a thermal ballast arranged in the temperature sensing cylinder and made by a ceramic sinter, which includes silica and alumina as its main components, so as to have at least one bore hole extending straight through in an axial direction of the temperature sensing cylinder and opening at both axial ends of the thermal ballast;

an operating fluid, sealed in the temperature sensing cylinder so as to change from a gas phase to a liquid phase and vice versa, in response to temperature sensed by the temperature sensing cylinder at an outlet of an evaporator of a refrigeration system; and

means for fixing the thermal ballast into a certain position in the temperature sensing cylinder so as not to prevent the operating fluid in the gas phase from making surface contact with the inner surface of the temperature sensing cylinder;

whereby the thermal ballast is able to trap and hold the operating fluid in the liquid phase inside the temperature sensing cylinder.