FR2739184A1 - Vacuum and temperature gauge for use in servicing refrigerator - Google Patents

Abstract

The vacuum meter for measuring two values of physical characteristics of a fluid comprises a box (1) housing a motor unit and amplifier movement (2). Above these is a pressure graduated dial (3) and a collar (5) fixed to the box by means of a threaded ring. This allows graduated dials to be fitted to the box as a function of the fluid being used. A plastic joint (5) and a transparent cover (8) ensure a seal for the box. In order to ensure correct positioning of the dial, a fixed pointed (7) is provided, and a scale determines where the dial should be in relation to the fixed pointer, according to a known temperature-pressure law.

Description

The present invention relates to a manovacuometer making it possible to read two physical values of the fluid controlled using a single device by means of removable graduations.

 i) This invention makes it possible to know using a single device, 2 physical values, of a fluid when there is a law of correspondence between these two values. It is suitable for measuring the temperature and pressure of the refrigerants used in refrigeration machines at the same time.

2) The refrigerants used until now were mainly CFCs and HCFCs, standardized products and listed under the headings R11 - R12- R22
R502.

The Montreal Convention, for the protection of the ozone layer prohibited
the use of CFCs according to a precise schedule. In order to be able to continue either to operate existing installations or to manufacture new machines, new products have been developed in accordance with the directives of the
Montreal.

All these products or mixtures are governed in their use by a law
temperature pressure specific to themselves. At each fluid temperature
corresponds to pressure and vice versa.

When filling a refrigerating machine with fluid, these two concepts
temperature, pressure are essential to know using indicators
manometer thermometer.

The indication of the pressure is independent of the fluid, on the other hand the indication of
the temperature as a function of the pressure depends on the type of fluid used.

There are already manovacuometers indicating on the same dial the pressure of the
fluid and the temperature of certain fluids, usually a maximum of three so
to be able to have an easy and reliable reading.

The number of substitution fluids has been largely developed by
producers. Manovacuometers previously used are no longer
usable. The large number of fluids does not allow printing on the same
dial the temperature corresponding to the pressure of these fluids.

 The object of the present invention is to use the same vacuum gauge indicating the pressure and to be able to use graduated dials also indicating the specific temperature of the fluid used by simple change of dial.

According to particular embodiments: - the dials can be placed in a pocket outside the
pressure gauge - the dials can be placed inside the pressure gauge, changing
requiring disassembly of the housing flange - the transparencies can be graduated and held on the housing using
flexible sleeve.

- on the back of the device can be placed several graduated transparencies.

 The accompanying drawings illustrate the invention.

Figures 1 and 2 show in section the interior layout of the
pressure gauge.

 Figures 3 and 4 show in section a variant of the manovacuometer.

 With reference to these drawings, the manovacuometer comprises a case (1) incorporating the motor member and the amplifying movement (2), the dial (3) is graduated in pressure units, the needle (4) covers the most short of the graduation, a collar (5) is fixed on the housing using a thread.

This flange allows to place graduated gutted dials (6) according to the
fluid used. Several graduated dials can be provided. The seal is ensured by a plastic seal and a transparent (8). In order to position the removable graduated dials relative to the pressure indication graduation, positioning pins (7) are provided in the housing, corresponding to holes made in the graduated dials (9).

- The dials can be directly printed on the transparency (10). The change in use of the fluid implies the change only of the
transparent.

 In the embodiment according to figure (3) the transparency (10) is directly graduated according to the fluid used, it is held on the casing of the manovacuometer using a flexible sleeve (11) ensuring a tightness of the dial on the housing. In order to be able to position the graduated transparency, centering pins (7) are provided on the housing.

In the transparent, corresponding positioning holes (9) are provided.

The graduated transparency is changed by spacing the lips of the flexible sleeve (11).

In an embodiment according to Figure (5) the flexible sleeve is extended (12) in the lower part in order to be able to maintain several graduated transparencies. Turning the edge of the lips of the flexible sleeve protects the graduated transparencies.

Claims (2)

 1) Vacuometer for measuring two values of physical characteristics of a fluid characterized in that it comprises a housing (1) comprising the motor member and the amplifying movement (2) and a dial graduated in pressure (3), a flange (5) fixed to the said housing (1) using a thread, making it possible to place graduated gutted dials (6) depending on the fluid, a plastic seal and a transparent (8) ensuring the seal. In order to properly position the removable dial relative to the fixed dial in order to comply with the temperature-pressure law, a positioning pin (7) is provided on the case. The removable dial has an imprint corresponding to this pin which is positioned relative to the graduation. 2) Device according to claim (1) characterized with regard to the change of the threaded collar by a flexible plastic collar (11) which allows the interchangeability of the removable dials.