GB2208068A

GB2208068A - Filter assembly

Info

Publication number: GB2208068A
Application number: GB8707928A
Authority: GB
Inventors: Philip Russell Hawkes
Original assignee: COOPERS AP FILTERS Ltd
Current assignee: COOPERS AP FILTERS Ltd
Priority date: 1987-04-02
Filing date: 1987-04-02
Publication date: 1989-02-22
Anticipated expiration: 2007-04-02
Also published as: GB8707928D0; GB2208068B

Abstract

A mounting for a screw-on filter 30 incorporates valve means automatically operable when the filter is unscrewed to minimize fluid loss during the latter operation. The mounting comprises a part 10 which partly unscrews from the main body 1 as the filter 30 is unscrewed from boss 12 and thereby allows poppet valve 4 to close the feed passage 2. Outlet passage 3 includes a spring-loaded ball valve 14 which closes automatically when the fluid flow stops. <IMAGE>

Description

Filter assembly This invention relates to a filter particularly suitable for treatment of automotive engine coolant fluids.

It is known to provide such filters in the form of a replaceable cartridge element adapted for installation by screwing it onto a mounting provided with the requisite inlet and outlet connections for fluid. Such cartridges are commonly termed spin-on filters; these words will be used throughout the following specification to describe such a replaceable cartridge element.

It is also known to provide spin-on filters containing fluid treatment additives such as anti-corrosion compounds. These dissolve during the life of the spin-on filter and are replenished when the latter has reached its service life and is replaced.

A common problem with spin-on filters is that on removal for inspection and/or for periodic replacement, there is some fluid loss from the inlet and outlet connections at the mounting. This loss may be large or small, depending on the relative height and disposition of the fluid reservoir. In some cases it will be necessary to drain the latter before unscrewing the filter. It is an object of this invention to provide a filter assembly with reduced fluid loss during installation or removal of a spin-on filter.

According to the present invention a mounting for a spin-on filter incorporates valve means automatically operable on removal of the filter to minimize fluid loss. The valve means may be spring biassed ball and/or poppet valves. The mounting preferably comprises a relatively fixed part and a relatively movable part together forming a common assembly in which the inlet/outlet pipework is connected to the fixed part, and the movable part is adapted to receive the spin-on filter.

Preferably the relatively movable part is provided with a conventional screw threaded adaptor to receive a conventionally-constructed spin-on filter, and the action of installing or removing such a filter causes relative movement of the mounting parts such that the valve means open or close, as appropriate.

This relative movement is most conveniently caused by providing a screw-threaded coarse pitch connection between the mounting parts. 11Relatively coarse" in this context means relative to the pitch of the conventional screw threaded connection between the spin-on filter and the movable part of the mounting. Preferably the desired relative movement of the parts of the latter to operate the 0 valve means is accomplished by a less-than-360 relative rotation, end stops being provided to control this rotation.

In order that the invention be better understood one embodiment of it will now be described by way of example with reference to the accompanying illustration in which: Figure 1 is a schematic cross-sectional side view of a mounting according to the invention, with a spin-on filter (part only shown) installed on it.

Figure 2 is a similar view of the mounting of Figure 1, but with the filter (again only partly shown) detached.

In Figure 1 the mounting comprises a casting 1 having screw threaded inlet and outlet ports 2, 3 respectively. The inlet port 2 leads directly into a chamber (downwardly-directed, in the figures) containing a poppet valve 4 biassed in the direction of a valve seat 5 by a helical spring 6.

In Figure 1 the valve 4 is open, allowing fluid communication through an aperture 7 defined by the seat 5, into an annular chamber S. From the latter fluid can freely pass through aperture 9 to filter itself. The latter need not be described in detail here, but (referring to both figures) it comprises an outer casing 30, a tubular filter element 31 and an end cap 32. The latter has at least one inlet aperture 33 which communicates with the outside of the filter element 31, and a screw threaded boss 34, the bore of which also serves as the filter outlet 35. The end cap includes the usual annular rubber sealing ring 36.

The casting 1 contains a relatively moveable part 10, to which it is connected by a relatively coarse pitched screw threaded connection 11. The part 10 has a screw threaded projecting spigot 12 onto which the filter element boss 34 can be screwed.

The spigot is hollow and, in use, communicates with the filter outlet 35 and with the inside of the filter element 31. The opposite end of the spigot terminates in a valve seat 13 against which a non-return ball valve 14 seats under the influence of a light coil spring 15. In Figure 1 the ball valve 14 is shown lifted off its seat as a result of the fluid flow through the filter outlet 3. In Figure 2 it is shown in the static, no-flow state, in which it blocks the outlet passage through the spigot 12.The part 10, which may be of a plastics materials with a metal insert carrying the necessary screw threaded portions, is rotatable relative to the mounting 1, in a cylindrical cavity in the latter. n sealing ring 16 is provided to prevent fluid loss through the annular interface between the mounting and the abutting relatively movable part 10. An end stop 17 (seen only in Figure 2) is provided to limit relative rotation of the respective parts, about a vertical axis in the 0 plane of the figures, to rather less than 360 The operation of the apparatus just described is as follows : - With the filter installed as in Figure 1, the action of screwing home the filter causes the spigot 12 and with it the part 10 to rotate, in effect screwing itself rapidly into the casting 10 because of the relatively coarse pitched threaded connection 11. This causes the part 10 to move upwards (in Figure 1) until it lifts the poppet valve 4 off seat 5, opening the passageway 7 through the latter. By the time this occurs, the filter and its seal 36 will have seated against the underside of the part 10, thereby preventing fluid loss. When fluid flow through the filter commences, it will unseat the ball 14, as shown in Figure 1.

However, on unscrewing the filter the opposite happens. Ball 14 seats when the flow ceases and initial rotation of the filter to unscrew it from the spigot 12 causes rotation of part 10 which thanks to the coarse threaded connection 11 descends rapidly. This in turn allows the poppet valve 4 to seat and close off flow from the inlet.

Further rotation to remove the filter thus results in minimal fluid loss, even though there Day be a considerable head of fluid above valve 4. Until the filter is replaced, the spring holds the valve closed; likewise at the outlet, the ball 14 will refrain on its seat until lifted by flow through the filter.

Claims

1. A mounting for a spin-on filter (as defined above incorporating valve means automatically operable on removal of the filter to minimize the fluid loss.

2. A mounting according to claim 1 wherein the valve means comprises ball and/or poppet valves.

3. A mounting according to claim 1 or claim 2 having a fixed and a relatively movable part adapted to receive the filter.

4. A mounting according to claim 3 wherein installation or removal of said filter causes relative movement of the parts and said movement opens or closes said valve means.

5. A mounting according to claim 3 or claim 4 wherein the fixed and movable parts are connected by a screw threaded coupling of relatively coarse pitch in relation to that of the connection to the spin-on filter.

6. A mounting according to claim 5 wherein including stop means operable to limit relative rotation of o the parts about a common axis to less than 360 the relative axial displacement of the parts on such rotation being sufficient to operate said valve means.

7. A mounting according to any preceding claim wherein a fluid inlet passageway is provided with a valve operable by installation of the filter and an outlet passageway is provided with a one-way valve responsive only to fluid flow through the filter.

8. A mounting for a spin-on filter substantially as described with reference to and as illustrated by the accompanying drawing.

9. The combination of a spin-on filter with a mounting according to any preceding claim.