GB2025575A

GB2025575A - Pressure compensating valve

Info

Publication number: GB2025575A
Application number: GB7914556A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-04-27
Filing date: 1979-04-26
Publication date: 1980-01-23
Also published as: FR2424461A1; ATA301579A; LU81193A1; BE875883A; IT7921429V0; NL7903203A; AT360056B

Abstract

A sealable compartment, such as a refrigerating compartment, includes a valve to compensate for air pressure differences due to varying temperatures for example. The valve comprises a relatively light spherical body (4) such as a table tennis ball, resting on a valve seat (3). A stop, for example defined by the wall of a tube (1) opposite the body (4) limits movement of the body away from the valve seat. A pair, or two groups, of valves may be provided to permit pressure compensating flow in both directions, Figures 6 to 8 (not shown). An associated heater keeps the valve free from ice. <IMAGE>

Description

SPECIFICATION A sealable compartment including an air pressure compensating valve This invention relates to a sealable compartment including an air pressure compensating valve. In particular the invention is concerned with e.g. refrigerating and fresh-keeping compartments, which are intended especially for the storage of foodstuffs.

With refrigerating and freshkeeping compart ments which are assembled from prefabricated elements at their place of installation there is a danger that upon rapid cooling to operating temper atures, which may lie with refrigerating compart ments in a temperature range between 18 and 27"C, the air temperature in the compartment is reduced very rapidly and a smaller air pressure relative to atmospheric pressure thereby arises in the compart ment. Also during operation of such a compartment, depending on the frequency and duration of the opening of e.g. a door, existing temperature differ ences occasionally cause large quantities of warm outside air to flow into the compartment which will then be cooled in a short time to the desired compartment temperature by an evaporator for example which will start immediately.

It has been established that even with a door opening time of 0.5 minutes, pressure differences of 2.4 to 2.9 millibars may arise. With relatively large compartments the danger of damage of compart ment elements, especially cover elements, cannot be excluded and it is necessary to ensure that pressure compensation can take place between the compart ment interior and the atmosphere.

Pressure compensating valves which operate with mechanical elements such as springs, flaps or the like are generally known. However, these known valves respond only at a relatively high pressure differences and, apart from their high cost of construction, may be liable to faults due to their design.

Moreover, pressure compensation takes place so slowly that the damger of compartment damage is not entirely excluded for long.

According to the invention there is provided a sealable compartment including an air pressure compensating valve comprising a relatively light spherical valve body resting on a valve seat and a stop for limiting movement of the valve body away from the valve seat.

In use, when the interior and exterior pressures are equal to the valve body, which may be e.g. a table-tennis ball or similarly constructed element lies on the valve seat. If e.g. a partial vacuum develops in the compartment interior, atmospheric air lifts the valve body and flows into the compartment until pressure compensation takes place. The valve seat is preferably designed so that e.g. the ball acting as the valve body falls back safety onto the seat upon pressure compensation. A built-in strip heater or the like is preferably provided to keep the valve free from ice. On the outside and inside of e.g. a compartment wall in which the valve is situated, openings are preferably closed with fine-meshed insect-proof lattices.

Warm air is used to defrost the evaporators of a refrigerating unit compartment. A brief pressure increase may thereby arise in the cell due to an increase of temperature. For this reason, it may be desirable to compensate for over-pressure in the compartment. Thus a valve may be installed turned through 1800C, changing the direction of action, as will be described in more detail below. For this purpose, the valve is preferably designed so that a partition step-shaped in cross section and having an opening defining the valve seat is arranged in a tubular member open at both ends.

To enable both underpressure and overpressure in the compartment to be compensated, two individual valves of this type which differ in their direction of action may also be combined into a double valve.

It is likewise possible to combine several single valves having the same direction of action if a larger flow of air is required for pressure compensation.

An alternative construction enabling flow in both directions includes a hollow member having an open top and an open bottom, two partitions extending across the interior of the member, one above the other, an aperture in each of the partitions defining a said valve seat, a said valve body resting on each valve seat, and a passage opening into the interior of the member in the space between the two valve seats.

Some embodiments of the invention will now be described by way of example and with reference to the accompanying schematic drawings in which: Figure 1 shows a pressure compensating valve in an element of a compartment in accordance with the invention; Figure 2 is a longitudinal section through the pressure compensating valve, with the direction of flow from outside inwardly; Figure 3 shows the pressure compensating valve according to Figure 2 viewed from the right; Figure 4 is a longitudinal section through a modified pressure compensating valve with the direction of flow from inside outwardly; Figure 5shows the pressure compensating valve according to Figure 4, viewed from the right; Figure 6 is a view of two combined pressure compensating valves forming a single unit and having differing directions of action; Figure 7 is a section through another embodiment of the invention; and Figure 8 is a partial section and view of the valve according to Figure 7, in the direction of the arrow A.

The pressure compensating valve of the embodiment according to Figures 1 to 3 consists of a plastic tubular piece which is adapted to the respective wall thickness of a compartment element 10 and in which is arranged a step-shaped partition 2 which for example, may be only glued in. Walls 11, 12 of partition 2 are cut to a szize respectively larger and rather smaller than semi-circular, there being arranged in a horizontal connecting portion 13 an opening 3 defining a valve seat for a light spherical valve body 4 e.g. a table-tennis ball and serving as a through-opening for pressure compensating air. Due to the low arrangement of the connecting face 13 relative to wall 11,there is formed a ball blocking bar 9 which guarantees that the ball always falls back onto the seat 3 when pressure compensation has taken place, by restricting lateral movement of the ball.Moreover, with this embodiment the wall of the tube 1, lying opposite the valve seat 3 forms itself a barrier to limit vertical movement of the ball. A strip heater 5 is provided, supplied with currentfrom a socket 14.

As shown in the alternative embodiment of Figure 4, the partition 2 may be turned through 1 80 C in relation to the valve axis 7, whereby the direction of action is changed. It would of course also be possible to install the entire tubular piece 1 of Figures 1 to 3 in the reverse direction relating to the compartment element 10, although the strip heater 5 would then likewise have to be changed over.

The openings of the tubular piece 1 may be shielded with lattices 6 such as lattices of fly-proof gauze or the like.

As shown in Figure 6 two tubular pieces 1, 1' of Figures 2 and 4 respectively may be combined into a single installation operating in both directions of flow.

The embodiment of Figures 7 and 8 is preferred for larger quantities of air for pressure compensation.

This arrangement includes a compensating tube 16 which is adapted to the respective wall thickness of a compartment element and in which a strip heater 5' is once again arranged, on the compartment side.

The compensating tube 16 rests in an opening 15 of a hollow member 1" which is open at the top and bottom. The partition 3" with several valve seat openings 2" is provided in the hollow member 1" above the opening 15 and a corresponding partition 3' with valve seats 2' is arranged underneath the opening 15. Reference numeral 4 designates small light valve bodies in the form of table-tannis balls which rest in the valve seat openings 2" and 2'.

Arranged above the two rows of table-tennis balls are valve-body blocking bars 6" and 6' which limit the lifting movements of the balls in case of through-flow. This embodiment permits compensation in both flow directions.

The entire valve, hence the tubular piece 1", compensating tube 16, partitions 3', 3" and bars 6' and 6" may be made from a suitable plastic.

The flat box shape of the hollow member 1" illustrated is not compulsory, albeit best suited for resting against the compartment element face, and the member 1" could also be made cylindrical with correspondingly adapted circular partitions. In this case small guide pins might have to be arranged between the valve bodies next to the valve seat openings, and such pins are suggested by broken lines in Figure 8.

Thus at least in the preferred embodiments there are provided pressure compensating valves which are of simple construction, respond even at very low pressure difference, can be incorporated into a wall element of the compartment without difficulty and, finally, due to their design offer the possibility of pressure compensation in both directions.

Claims

1. A sealable compartment including an air pressure compensating valve comprising a relatively light spherical valve body resting on a valve seat and a stop for limiting movement of the valve body away from the valve seat.

2. A compartment as claimed in claim 1 wherein the valve seat is formed as an aperture in a partition disposed in a passage communicating the interior of the compartment with the exterior thereof.

3. A compartment as claimed in claim 2 wherein the partition is stepped.

4. A compartment as claimed in claim 2 or 3 wherein the partition is provided with a bar for restricting lateral movement of the valve body.

5. A compartment as claimed in any preceding claim, including two of said air pressure compensating valves, respectively permitting flows in opposite directions.

6. A compartment as claimed in claim 5, wherein there is provided a hollow member having an open top and an open bottom, two partitions extending across the interior of the member, one above the other, an aperture in each of the partitions defining a said valve seat, a said valve body resting on each valve seat, and a passage opening into the interior of the member in the space between the two valve seats.

7. A compartment as claimed in claim 6 wherein each of said partitions is provided with a plurality of apertures defining a plurality of valve seats.

8. A compartment as claimed in claim 6 or 7 wherein the said passage opening into the interior of the member is in the form of a horizontally extending tube.

9. A compartment as claimed in claim 6,7 or 8 wherein said hollow member is in the form of a flat box.

10. A compartment as claimed in any preceding clam wherein a heater is provided for the or each valve.

11. A compartment as claimed in claim 10 wherein said heater is in the form of an electric strip heater.

12. A compartment as claimed in any preceding claim wherein openings Communicating with the valve and the interior of the compartment are covered by a lattice.

13. A sealable compartment including an air pressure compensating valve substantially as hereinbefore described with reference to Figures 1 to 6; or7 and 8, of the accomp,anying drawings.