Gas separation – With means securing or retaining separating media – Unit or cohesive sheet-like media in flow line or frame
Reexamination Certificate
2000-08-28
2002-06-25
Smith, Duane (Department: 1724)
Gas separation
With means securing or retaining separating media
Unit or cohesive sheet-like media in flow line or frame
C055S317000, C055S322000, C055S327000, C055S490000, C055S509000, C055S513000, C055S498000, C055S502000, C055S508000
Reexamination Certificate
active
06409786
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a filter assembly for collecting material that is entrained in a gas stream such as particulate solid material or liquid in an aerosol form, and to a tubular filter element for location in a housing to collect such material.
2. Present Stated of the Art
Filtration of gas in a compressed gas system is generally required so that the gas is sufficiently clean for a subsequent application or to minimise adverse effects of impurities on components of the system. For example removal of compressor oil can be required to minimise chemical contamination and accumulation on valves which might lead to malfunction of the valves, and removal of particulate solid material can be required to minimise abrasion.
A known filter assembly for use in compressed gas systems is sold by Domnick Hunter Limited under the trade mark OIL-X. It comprises a housing having inlet and outlet ports for the gas stream that is to be filtered, and a tubular filter element which can be located in the housing and is configured for the gas stream to flow through its wall, for example generally outwardly from the inside of the filter element to the outside. When the assembly is used to collect liquid in the gas stream (for example which is carried in the stream as an aerosol), the filter element will cause the liquid to coalesce. Coalesced liquid then drains from the filter element and collects in the housing for discharge. For such applications, the housing will include an outlet for discharge of any collected liquid.
The housing of such a filter assembly comprises a body section in which the tubular filter element is located and in which a reservoir for any collected liquid can be provided, and a head end cap with the inlet and outlet ports for the gas stream. The filter element comprises a filter medium and first and second end fittings by which the filter medium is supported within the housing. The end fitting at the end of the filter element remote from the head end cap is connected to the housing end cap by means of a tie rod which extends through the tubular cavity within the filter element and engages the end cap by means of a thread. The seal between the filter element and the end cap can depend to a degree on the accuracy with which the assembler interconnects the element and the end cap using the tie rod. A less reliable seal might result if for example the threads on the tie rod and the end cap are dirty which restricts mating of the threads. Moreover, the assembler may not be able easily to detect this defect.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a filter assembly in which a tubular member is sealingly connected to a housing in fluid communication a port therein, and bears a resiliently deformable tang which can be received in a recess in the housing when the tubular member and the housing are properly assembled.
Accordingly, in one aspect, the invention provides a filter assembly for collecting material that is entrained in a gas stream, which comprises:
(a) a housing having inlet and outlet ports for the gas that is to be filtered, in which a tubular filter can be located arranged for the gas stream to flow through its wall provided by a filter medium, and
(b) a tubular member which can be sealingly connected in fluid communication with one of the ports in the housing, the tubular member bearing at least tang,
the housing having a recess in its internal side wall in which the tang can be received when the tubular member is properly located within the housing to form a seal to the said port.
The assembly of the invention has the advantage that the assembler can recognise when a secure connection has been made between the tubular member and the housing once the tang has been received in the recess. Furthermore, by appropriate configuration of the tang and the recess, the location of the tang in the recess can prevent inadvertent or unwanted separation of the housing and the filter element. Accordingly, the invention provides control over the seal that is formed between the housing and the tubular member. This is important to ensure safe and efficient operation of the assembly.
Generally, the housing will comprise an end cap and a body section in which the filter element is located when the assembly is in use. One or more ports for gas to be filtered can then be provided in the end cap; the end cap can then accommodate the flow conduit within it when the assembly is in use to provide a flow path for gas to be filtered between one of the ports and the filter element located in the housing body section. A filter assembly which comprises a housing having a body section and an end cap, with a flow conduit received in the end cap, is disclosed in WO-A-99/30799 (which claims priority from UK patent applications nos. 9726415.4 and 9815959.3 and which has the same filing, priority and publication dates as the present application). Subject matter disclosed in that document is incorporated in the specification of the present application by this reference.
When the housing comprises an end cap and a body section, the assembly of the invention has the advantage of facilitating assembly of the housing. The tang can retain a filter element engaged with the end cap prior to assembly of the end cap and body section of the housing. The operator is therefore able first to assemble together the filter element and the end cap, then to assembly together the body section and the filter element end cap combination.
Preferably, the tang is deformable, especially resiliently, to enable it to be received and located in its recess, especially as the tubular member and the housing are introduced to one another and assembled. Preferably, the tang is arranged so that it is deformed transversely relative to the axis of the filter element. It will generally be deformed transversely inwardly, towards the said axis.
Preferably, the tang includes a projection by which the tang can be depressed to disengage it from the recess. For example, the tang can have first and second projecting portions at or towards its end, arranged at an angle to one another. The first of the projecting portions can be received in the recess and the second projecting portion can be used to depress the tang to disengage the first projecting portion from the recess.
The tubular member can be provided with more than one tang, for example two, three four or more tangs. The arrangement of the tangs around the tubular member will be arranged to match that of the recesses in the housing. Often, when there are a plurality of tangs, they will be arranged with uniform spacing around the tubular member. Different arrangements of tangs and recesses can be used to differentiate products, for example because of different technical specifications, to ensure that a tubular member is always used in an appropriate housing.
The tubular member is in fluid communication with one or more inlet ports or one or more outlet ports in the housing, providing a path for flow of the stream of the gas that is to be filtered between the port(s) and tubular cavity within the filter element that is defined by the filter medium.
Preferably, the recess is provided in the housing so that location of the tang in the recess can provide an indication that the tubular member has been located in the housing.
Preferably, the recess has an associated ramp portion to cause the tang to be deformed as the tang approaches the recess during introduction of the tubular member into the housing. Generally, the ramp is arranged facing along the axis of the filter element so that the tang is deformed when the tubular member is moved along the axis of the assembly. Other configurations of ramp will be appropriate if the movement of the tubular member into the housing involves other movement such as rotation.
Generally, the flow of the gas stream towards and away from the assembly will be generally horizontal. The tubular filter element will generally be arranged vertically so that the port referred to above is arr
Bateman Alan
Lane Brian
Shaw Paul David
Smith Stephen Nicholas
Wright Kenneth
Domnick Hunter Limited
Pham Minh-Chau T.
Smith Duane
Workman & Nydegger & Seeley
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