Patent Application
20250116354
This application claims the benefit of European Patent Application No. 23461664.7 filed Oct. 10, 2023, the disclosure of which is incorporated herein by reference in its entirety.
The present disclosure is concerned with providing heating for valves and valve components e.g. to prevent freezing.
Valves of many types are known to regulate the flow of fluid through a system. Such valves can be manual or motorized. Mechanical, hydraulic and electrical valves are known and used in many fields. Often, such valves and associated pipes are required to operate in extreme environments and are required to be able to continue to operate reliably in environments where e.g. contamination, vibration, pressure and or temperatures can impact operation. One field of application where the valve components are subjected to particularly low temperatures is in the aerospace field. Valves are used to drain fluid from water systems in the aircraft or to drain water that has accumulated in parts of the aircraft such as the fuel tank. Valves are also used in vacuum toilets used e.g. (but not only) in aircraft. An example of such valves is a check valve, or bypass check valve, that is incorporated between the vacuum pump or generator and the waste tank of a vacuum toilet. The bypass check valve is arranged to open in the event of excess pressure in the vacuum—waste tank line to depressurise the line. Components such as water pipes and valves designed for aerospace applications often face many unique challenges. One of the main challenges is high altitude operation with ambient temperatures around −45° C. (−50° F.). At such temperatures, water in or around the valve parts can freeze and prevent reliable operation of the valve. In bypass check valves, for example, if the valve is not positioned in a location with climate control, and/or if the valve is oriented such that condensation can accumulate in the valve, the valve parts can become frozen and inoperable, which can lead to damage to the overall system of which the check valve is a part. Valves can become frozen in a completely closed or partially open position. For this reason, many valves require some form of heating to prevent water in or on the valve from freezing.
Typically, silicone heaters are used since these can be formed as flexible sheets or sleeves and fitted around the parts of the valve that require heating.
Although silicone heaters provide an effective and simple solution, silicone has fairly low mechanical properties and so can be damaged during installation or during normal use of the valve and may need to be replaced frequently. Further, the known silicone heaters are provided as a layer around the valve/pipes. This results in an overall increase of the size of the valve/pipes and therefore requires more space for installation. In aircraft, and other applications where space is limited, this can be disadvantageous.
There is, therefore, a need for a simple way of providing heating to valves that avoids these problems.
According to this disclosure, there is provided a heated valve assembly, comprising a valve housing defining a fluid flow passage therethrough from a first housing end to a second housing end, a moveable valve part and a valve seat located within the fluid flow passage, wherein the movable valve part moves relative to the valve seat responsive to a pressure differential between the first housing end and the second housing end, the moveable valve part moving between a closed position in sealing engagement with the valve seat and an open position spaced from the valve seat to allow fluid flow past the movable valve part from the first housing end to the second housing end, and wherein a heater is incorporated in the valve seat.
Examples of the heated valve assembly of the disclosure will be described below with reference to the drawings. It should be noted that variations are possible within the scope of the claims.
The arrangement will be described with particular reference to valves used in aerospace, particularly check valves, such as used as bypass check valves in vacuum toilets, but the inventive concept can be equally applied to valves used in other applications where heating is required and the scope of the invention is not limited to any particular application or type of valve.
One example of a valve assembly to which the heating arrangement described herein could be applied is a check valve, e.g. a bypass check valve as shown in
An example of a check valve is an umbrella valve such as shown in
As mentioned above, if this check valve is exposed to very cold temperatures and moisture accumulates, the moveable umbrella part can freeze and become stuck in a particular valve position. The same problem can arise with the moveable valve element of other types of valve.
The valve design according to this disclosure addresses this problem by providing a modified valve seat incorporating a heater. This is explained further with reference to the example shown in
The solution according to the disclosure is to provide a valve seat 100 in the form of a valve seat housing 102 configured to be located across the interior of the valve housing 104. The valve seat housing may be located on an inwardly extending valve housing flange 106 such as a flange that currently defines the valve seat for existing valves. Taking that approach means that the modified valve seat housing could be retro-fitted to existing valve housings. It is, however, also feasible that the valve seat housing of the disclosure is mounted in or formed integrally with the valve housing in other ways. The valve seat housing defines an opening 108 therethrough. A moveable valve element 300, in this example an umbrella as described in relation to
The valve seat housing 102 is made of thermally conductive material. Furthermore, the valve seat housing houses one or more heater elements 306. Power is provided to the heaters via e.g. wires 308 extending out from the valve housing. The one or more heater elements are enclosed or encased within the valve seat housing 102 conductive material and are, therefore, protected by the valve seat housing from water etc. within the valve body 104. The heater element(s) 306 is/are preferably fitted into the valve seat housing before the valve seat housing is mounted into the valve housing, so that the valve seat is assembled with the heater element(s) pre-installed. The heater elements may be incorporated into the valve seat housing e.g. by press-fitting, by use of adhesive or in other ways.
In the example shown, an annular heater element 302 is incorporated into the housing to provide heating where the risk of ice bonding to the parts is highest, but other configurations are possible.
Because the valve seat housing is made of thermally conductive material (preferably with high thermal conductivity) the heat from the heaters will spread to the location where the umbrella stem 304, in this case, extends through the opening 108. This prevents freezing and, thus, strain on this part of the valve. The heater elements ensure that the moveable valve part remains moveable relative to the valve seat even at very low temperatures, thus ensuring that the valve continues to function reliably.
As the heater is located in the valve seat and, therefore, close to where the risk of ice bonding is highest, the advantages of heating the valve can be obtained using relatively small heater elements that draw relative low power.
Operation of the valve, per se—i.e. how it opens and closes is unchanged. For an umbrella valve, this is described above with reference to
| Number | Date | Country | Kind |
|---|---|---|---|
| 23461664.7 | Oct 2023 | EP | regional |
