GB2255827A

GB2255827A - Pressure indicator in pipeline

Info

Publication number: GB2255827A
Application number: GB9110268A
Authority: GB
Inventors: Ronald Pardy
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1991-05-11
Filing date: 1991-05-11
Publication date: 1992-11-18
Anticipated expiration: 2011-05-11
Also published as: GB9110268D0; GB2255827B

Abstract

A pressure indicator incorporated in a fluid line is built into a connector which connects two pipes in the fluid line. Two components (20, 22) of the connector are arranged so that one is secured to one of the pipes (10) and the other is secured to the other of the pipes (12) to provide a leak-free connection between the pipes. The two components can however move relative to one another to indicate a pressure in the fluid line above a pre-set threshold value when indicating band (36) becomes visible. <IMAGE>

Description

PRESSURE INDICATOR This invention relates to a pressure indicator, particularly for use in indicating a pressure rise in a fluid flow system resulting from a clogged fluid filter in the system. The invention also provides a fluid line connector which incorporates a pressure indicator.

Many fluid flow systems incorporate filters through which the fluid must pass, and during the life of such filters they can become clogged, leading to a reduction in fluid flow through the system. One example of such a system is the fuel system in a motor vehicle. Under normal operating conditions, the filter is unlikely to become clogged, but if a fuel supply fault occurs, suspicion often falls first on the filter and many filters are replaced unnecessarily.

Filter clogging indicators are known (eg GB-A-2 099 150) in which a pressure rise produces a physical movement of a readily visible component to indicate that filter replacement is necessary.

Rnown filter clogging indicators however are generally complex and occupy a substantial amount of space. In a number of cases, the indicators form part of the filter unit itself and are thrown away with the clogged filter.

According to the invention, there is provided a pressure indicator for indicating an excessive pressure in a fluid flow line, the indicator comprising two relatively movable components, each of which includes afluid flow passage, the two components being arranged in series with one another to form part of the fluid flow line and having opposed surfaces exposed to the pressure of fluid in the line, and a resilient device for holding the components in a first relative position whilst the pressure in the line is below a threshold value, which device can yield to allow the components to move to a second relative position when the pressure in the line exceeds the threshold value, and wherein at least one of the components carries a visible marking which is concealed in the first relative position and is revealed in the second relative position.

Known filter clogging indicators require substantial additional componentry in addition to the filter and the fluid flow line itself, and it is an advantage of the invention that it can be incorporated directly and simply in existing parts of the fluid flow line.

The invention also provides a fluid line connector adapted to connect two pipes in a fluid flow line, the connector including pressure indicating means for indicating an excessive pressure in the flow line, wherein the connector comprises two relatively movable components, at least one of the components having surfaces exposed to the pressure of fluid in the line, a resilient device for holding the components in a first relative position whilst the pressure in the line is below a threshold value and which can yield to allow the components to move to a second relative position when the pressure in the line exceeds the threshold value, at least one of the components carrying a visible marking which is concealed in the first relative position and is revealed in the second relative position.

The connector may have a socket at one end for receiving one pipe end. The socket may receive the pipe end by a push-fit action, with the pipe being gripped in the connector by a toothed collet which has limited axial movement in the connector. At the other end, the connector may have a tubular spigot with fir-tree rings on its outer surface, so that a flexible pipe can be pushed over the spigot.

In an alternative embodiment, the pipe can be received in the socket by a snap-in action, with a shoulder on the pipe being retained behind a spring clip on the connector.

One component of the connector can form the socket, and the other component can form the spigot. When a pipe end is fitted in the socket, a seal is preferably formed between the pipe outer surface and the other component.

The resilient device may be a spring clip which intrudes into the cross-section of the connector and normally holds the two components in a first relative position. Alternatively, the resilient device may be a moulded part of one component which engages resiliently with a moulded part on the other component to provide the necessary location and yielding functions.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of a fuel system in an internal combustion engine installation; Figure 2 is a cross-section through a connector in accordance with the invention, illustrating two different operating states; Figure 3 is a cross-section through the connector of Figure 2, on the lines III-III; Figure 4 is an external view of the connector, on a smaller scale; Figure 5 is a detail of part of a second embodiment of connector in accordance with the invention; Figure 6 is a side view, partly in section, of a third embodiment of connector in accordance with the invention; Figure 7 is an external plan view, on a smaller scale, of the connector of Figure 6; and Figure 8 shows one component of the connector of Figures 6 and 7.

Figure 1 shows an installation with an automobile engine 2 and a fuel tank 3. The engine and the tank are connected by feed and return lines 4 and 5. A pump 6 with a built-in filter 7 is mounted in the tank 3, and an engine fuel filter 10 is fitted in the feed line 4. The filter 10 is connected in the line 4 by connectors 8 and 9. The rest of this description is concerned with the construction of the connector 8.

Figure 2 shows the filter housing 10 connected to the feed line which in this case is a flexible tube 12 by a connector 14. The filter housing has a stub pipe 16 projecting from the housing, and this is received in a socket 18 in a first connector member 20. A second connector member 22 is fitted inside the first member, and the outside surface of the stub pipe 16 is sealed to the inside surface of the second connector member by two O-ring seals 24 and 26. A fluid path is therefore established from the tube 12, through the connector 14 to the filter 10.

The stub pipe 16 and the connector are secured to one another by means of a known mechanism. The first housing part 20 includes an annular collet 28 which has internally directed teeth 30 mounted on a radially flexible skirt. When the pipe 16 is inserted, the teeth splay outwards to allow the pipe to enter.

When the pipe is pulled in an outward direction however, the teeth bite into the surface of the pipe and resist removal. A pair of lugs 32 at the mouth of the socket can however be pushed inwards to hold the collet in a position where the teeth do not hinder removal of the pipe.

The first and second connector components 20 and 22 can take up two alternative relative positions. In the top half of Figure 1, the second component is retained behind a spring clip 34, and a 'filter clogged' indicator band 36 is concealed within the first component. In the lower half of Figure 1, the second component has escaped the spring clip 34 and is retained behind a flange 38. In this position, the indicator band 36 is exposed. The indicator band will probably be of a bright, highly visible colour so that the installation can be easily inspected to determine whether the filter needs to be replaced or cleaned.

After fitting a new filter, the connector is reset by pressing the second component back into the first component, by finger pressure, until the position shown in the top half of Figure 2 is restored.

The spring clip 34 is shown in more detail in Figure 2. The clip is of bent wire and extends into the internal cylindrical space of the first part 20, through cut-outs 42 in the walls. The clip engages with an angled external wall 44 on the second part 22, but when the second part is pushed in an axial direction, the spring clip will be cammed outwardly so that the second part can pass.

The internal pressure in the fluid line will act on surfaces 38 and 40 of the second connector. Under normal conditions, the resulting axial force will be insufficient to overcome the resistance offered by the spring clip 34, and the band 36 will remain concealed. However when the filter 10 becomes clogged, the fluid pressure upstream of the filter will rise, and there will come a point at which the pressure acting on the surfaces 38 and 40 will be sufficient to push past the clip 36. When this happens, the second component will move to the position where the band 36 is exposed, as shown in the lower half of Figure 1, and it will then be readily apparent that the filter needs changing or clearing.

Instead of the spring clip 34, other yieldable retention devices are possible. Figure 4 shows retention being achieved by a moulded lug 46 on the second part 22, which can be forced past a lip 48 on the second part when the threshold pressure is reached.

Claims

1. A pressure indicator for indicating an excessive pressure in a fluid flow line, the indicator comprising two relatively movable components, each of which includes a fluid flow passage, the two components being arranged in series with one another to form part of the fluid flow line and having opposed surfaces exposed to the pressure of fluid in the line, and a resilient device for holding the components in a first relative position whilst the pressure in the line is below a threshold value, which device can yield to allow the components to move to a second relative position when the pressure in the line exceeds the threshold value, and wherein at least one of the components carries a visible marking which is concealed in the first relative position and is revealed in the second relative position.

2. A fluid line connector adapted to connect two pipes in a fluid flow line, the connector including a pressure indicator for indicating an excessive pressure in the flow line and comprising two relatively movable components, at least one of the components having surfaces exposed to the pressure of fluid in the line, a resilient device for holding the components in a first relative position whilst the pressure in the line is below a threshold value, the device being adapted to yield to allow the components to move to a second relative position when the pressure in the line exceeds the threshold value, and wherein at least one of the components carries a visible marking which is concealed in the first relative position and is revealed in the second relative position.

3. A connector as claimed in Claim 2, which includes a socket at one end for receiving one pipe end by a push-fit action, with the pipe being gripped in the connector by a toothed collet which has limited axial movement in the connector.

4. A connector as claimed in Claim 2 or Claim 3, which includes a tubular spigot with fir-tree rings on its outer surface, so that a flexible pipe can be pushed over the spigot.

5. A connector as claimed in any one of claims 2 to 4, wherein one component of the connector includes the socket, and the other component includes the spigot.

6. A connector as claimed in any preceding claim, wherein a seal is formed between the pipe outer surface and the other component.

7. A connector as claimed in Claim 2, wherein the pipe is received in the socket by a snap-in action, with a shoulder on the pipe being retained behind a spring clip on the connector.

8. A connector as claimed in any one of Claims 2 to 7, wherein the resilient device is a spring clip which intrudes into the cross-section of the connector and normally holds the two components in a first relative position.

9. A connector as claimed in any one of Claims 2 to 7, wherein the resilient device is a moulded part of one component which engages resiliently with a moulded part on the other component to provide the necessary location and yielding functions.

10. A pressure indicator as claimed in Claim 1, wherein the resilient device is a spring clip which normally holds the two components in a first relative position.

11. A pressure indicator as claimed in Claim 1, wherein the resilient device is a moulded part of one component which engages resiliently with a moulded part on the other component to provide the necessary location and yielding functions.

12. A pressure indicator substantially as herein described with reference to any one embodiment shown in the accompanying drawings.

13. A fluid line connector substantially as herein described with reference to any one embodiment shown in the accompanying drawings.