Sensing unit for detecting refrigerant leak sealant additive

• US 20050005680A1
• Filed: 07/28/2004
• Published: 01/13/2005
• Est. Priority Date: 09/17/2002
• Status: Abandoned Application

• Current Assignee: Neutronics, Inc. (MSA Safety, Inc.)
• Original Assignee: Neutronics, Inc. (MSA Safety, Inc.)
• Inventors: Anderson, J. Douglas
• Application Number:
  US10/900,628
• Publication Number:
  US 20050005680A1
• Time in Patent Office: Days
• US Class Current: 73/40
• CPC Class Codes: F25B 2345/006 characterised by charging or discharging valves
• CPC Class Codes: F25B 45/00 Arrangements for charging or discharging refrigerant
• CPC Class Codes: G01M 3/042 by using materials which expand, contract, disintegrate, or decompose in contact with a fluid G01M3/12 takes precedence
• CPC Class Codes: G01N 7/10 by allowing diffusion of components through a porous wall and measuring a pressure or volume difference

Abstract

A device for determining the presence or absence of refrigerant leak sealant within the refrigerant charge of air conditioning systems or stores is described. A sensing unit having a seal-forming surface is wetted and placed in fluid communication with a refrigerant access port of the air conditioning system. A depressor opens the refrigerant port and refrigerant begins to flow through the sensing unit. If any leak sealant is present in the refrigerant charge, a sealant plug begins to form on the seal-forming surface and reduces the flow rate of the refrigerant through the sensing unit, thereby indicating the presence of the sealant. Refrigerant charges that do not contain a leak sealant will flow through the sensing unit at a substantially constant rate, indicating the absence of sealant.

Claims

1. A sensing unit for use with a device for detecting the presence or absence of a leak sealant additive in an air conditioning charge, the sensing unit comprising:

an inlet for admitting refrigerant, an outlet for exhausting the refrigerant;

a passage between the inlet and the outlet; and

a seal-forming surface within the passage on which leak sealant additive can form a sealant plug to at least partially restrict refrigerant flow from the inlet to the outlet.

2. The sensing unit of claim 1 wherein the seal-forming surface comprises a porous insert between the inlet and the outlet.

3. The sensing unit of claim 2 wherein the porous insert comprises sintered metal.

4. The sensing unit of claim 1 wherein the passage comprises a machined orifice and wherein the seal-forming surface comprises a surface adjacent the machined orifice.

5. The sensing unit of claim 1 wherein the seal-forming surface defines a flow restrictor that allows less than five percent of the refrigerant charge to pass in three minutes.

6. The sensing unit of claim 1 wherein the seal-forming surface defines a flow restrictor that limits refrigerant flow to between about 100 cm³/min and about 1000 cm³/min from a refrigerant source at 60 to 200 psig.