GB2296955A - Improvements relating to silt extractors - Google Patents

Abstract

A silt extractor for insertion in a pipeline comprises a pipe section 1 with an annular chamber 8 surrounding the main passage 9, an outlet 2 branching upwardly from the top of the chamber 8, and an aperture 7 in the inner wall of the chamber on the opposite lower side of said passage. The pipe section may be a T-joint with a stem 2 extending upwardly. The arms of the T are larger in diameter than the pipeline, but taper at their ends 4. A tubular insert 5 lies coaxially within the arms, its ends sealingly wedged against the tapers. The aperture 7 may be elongated in the direction of flow and keyhole shaped and extends along the lower side of this insert, opposite the stem 2 and silt drops through it to accumulate in the lower part of the annular chamber 8 found between the insert and the arms of the T. This can periodically be purged by opening a valve or stopcock in or downstream of the stem.

Description

'tImprovements relating to Silt Extractors This invention relates to silt extractors.

Silt tends to accumulate in liquid pipelines, which consequently need cleaning or flushing out from time to time. One technique is to provide silt traps, where the silt will tend to accumulate in preference to other parts of the pipelines, and then provision is made for removing the silt from the traps. One of the commonest examples is to be found under almost any domestic sink or basin.

However, when the pipeline is continuously filled with liquid (unlike a drain) different measures are appropriate and it is the aim of this invention to provide a silt trap where the liquid itself can be diverted and used for purging the trap.

According to the present invention there is provided a silt extraction device for a liquid pipeline comprising a pipe section with an annular chamber surrounding the main passage therethrough, an outlet branching upwardly from the top of said chamber, and an aperture in the inner wall of the chamber only on the opposite, lower side of such passage.

Preferably, the aperture will be elongated in the direction of flow, and it may be wider upstream than downstream. A keyhole shape may be the most suitable. The wide part will generally be slightly upstream of the outlet.

Conveniently, the annular chamber will be formed by an enlargement of the main body of the pipe section to define its outer wall and a tubular insert to define its inner wall and a section of the main passage. The enlargement may be a T joint, the stem providing the outlet, and the arms providing the outer wall of the annular chamber. These may be joined at their ends to reducing collars which will couple to the pipeline, and conveniently the tubular insert is sealed at its ends to the inner tapering walls of the reducing collars. It can be held in place simply by a wedging action at each end.

For a better understanding of the invention, one embodiment will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an axial section of a silt extraction device, Figure 2 is an underneath plan view of an inner tube forming part of that device, and Figure 3 is an enlarged view of part of Figure 1.

The device has a T-joint 1 formed from two similar plastics mouldings bonded together. Its flanged stem 2 provides an outlet passage which can be coupled to a valve or stopcock (not shown), possibly through an intermediate pipe. The ends of the arms 3 of the T have flanged couplings to reducing collars 4, also of moulded plastics material.

These are frusto-conical both inside and out, and their smaller ends are flanged to couple to a pipeline (not shown).

Within this assembly is trapped a tubular insert 5. Its ends are sheathed by resilient sleeves 6 which form seals by wedging against the inner surfaces of the reducing collars 4. The insert 5 is thereby held co-axial with the collars 4 and the arms 3.

The insert 5 has a keyhole shaped aperture 7 at about its mid-length. It is elongate in the direction of flow, and the circular part will be upstream. The insert is oriented so that this aperture 7 is lowermost, on the opposite side from the upwardly extending outlet 2. The circular portion is slightly upstream of the axis of that outlet.

It will be seen that an annular chamber 8 is formed around the main passage 9, which is maintained with a substantially constant cross-section. Silt and other matter in the flowing liquid will tend to drift down through the aperture 7 and settle in the bottom of the annular chamber 8, where the liquid will be virtually stagnant. But when the stopcock or valve in the outlet 2 is opened, liquid will be drawn from the chamber 8, both sides will be swept by the escaping liquid and the chamber will be replenished by liquid from the main passage 9 passing down through the aperture 7. The silt will be entrained by the escaping liquid and pass out through the outlet 2. When the chamber 8 is purged of silt, the outlet is closed again and normal flow resumes.

Claims (11)

1. A silt extraction device for a liquid pipeline comprising a pipe section with an annular chamber surrounding the main passage therethrough, an outlet branching upwardly from the top of said chamber, and an aperture in the inner wall of the chamber on the opposite, lower side of said passage.

2. A silt extraction device as claimed in Claim 1, wherein the aperture is elongated in the direction of flow.

3. A silt extraction device as claimed in Claim 2, wherein the aperture is wider upstream than downstream.

4. A silt extraction device as claimed in Claim 3, wherein the aperture is keyhole shaped.

5. A silt extraction device as claimed in Claim 3 or 4, wherein the wide part is slightly upstream of the outlet.

6. A silt extraction device as claimed in any preceding claim, wherein the chamber is formed by an enlargement of the main body of the pipe section to define its outer wall and a tubular insert to define its inner wall and a section of the main passage.

7. A silt extraction device as claimed in Claim 6, wherein the enlargement is a T-joint, the stem providing the outlet, and the arms providing the outer wall of the annular chamber.

8. A silt extraction device as claimed in Claim 7, wherein the arms are joined at their ends to reducing collars which will couple to the pipeline.

9. A silt extraction device as claimed in Claim 8, wherein the tubular insert is sealed at its ends to the inner tapering walls of the reducing collars.

10. A silt extraction device as claimed in Claim 9, wherein the sealing of the tubular insert is by wedging action at each end.

11. A silt extraction device substantially as hereinbefore described with reference to the accompanying drawings.