Refrigerant metering charge board and method of its operation
US5694778A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 21, 1995 |
| Grant date | Dec 9, 1997 |
| Priority date | — |
| Expiry date | Jul 21, 2015 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25B2345/005
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A refrigerant metering charge board that accurately meters a refrigerant and an associated synthetic compressor oil into a product, preferably a refrigerator, is provided. Metering is accomplished by way of servo motors coupled to ball screws which are in turn connected to hydraulic cylinders. Calibration of the refrigerant, preferably R134a, is maintained using a temperature sensor, a programmable logic controller (PLC) and a density/temperature equation that has been empirically fit to saturation data. The preferred equation is a modified Benedict-Webb-Ruben (MBWR) equation of state. The refrigerant charge amounts are entered into the PLC using either a fixed bar code scanner or a hand-held bar code scanner that reads a bar code on the refrigerator. An operator interface, preferably a touch-screen display is also provided. A charging tool to connect to the product for inserting the refrigerant is located in a chargeable automatic connect/disconnect mechanism (ACDM) which allows for automatic operation on a assembly line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.