GB2045374A - Standpipes for hydrants - Google Patents

Abstract

The invention relates to standpipes for water hydrants. Hitherto standpipes have been constructed as a metal tube secured at its lower end to a base or socket by welding to ensure a leak free joint. This has the disadvantage of reducing the mechanical properties of the tube thus necessitating the use of thicker walled tubes than would otherwise be necessary. The objective of the invention is to avoid welded constructions, and this objective is met in a construction comprising a tubular body (1), the lower end of which fits into a separately formed socket or base (2), part of the tube within the socket having been expanded into contact with the inner wall of the socket, which inner wall is provided with formations (4 and 5) whereby following expansion of the said part of the tube, the tube and the socket become mechanically interlocked to form a leak-proof joint. <IMAGE>

Description

SPECIFICATION Standpipes for hydrants This invention relates to standpipes for use with hydrants.

It has been common practice for many years to provide strategically placed hydrants connected to a mains water supply, for the supply of water for, e.g., fire fitting purposes or for the controlled supply of water in times of water shortage. To allow for the dispensing of water from a hydrant it is equally common practice to provide a standpipe which is connected to the hydrant and has a normally closed valved outlet for connection, e.g., to a fire hose. Standpipes presently in use are normally constructed from a metal tube secured at its lower end to a metal socket or base, the socket having internal threads for connection to the hydrant.The metal tube is normally welded to the socket and which has the major disadvantage of reducing the mechanical properties of the tube which has led to the use of thicker walled tubing than would be otherwise necessary in an attempt to compensate for the reduced mechanical properties.

The object of the present invention is to provide a standpipe for use with hydrants which avoids the need for a welded construction.

According to the present invention, a standpipe for use with hydrants comprises a tubular body, the lower end of which fits into a separately formed socket or base, part of the tube within the socket having been expanded into contact with the inner wall of the socket, which inner wall is provided with formations whereby following expansion of the said part of the tube, the tube and the socket become mechanically interlocked to form a leak-proof joint.

Thus, the joint between the tube and the socket is formed cold and consequently the mechanical properties of each part, particularly the tube, are not impaired. This has the direct effect of allowing the use of a tube wall thickness smaller than that of a comparable welded construction and yet of sufficient strength to fully meet the requirements of British Standard Number 336.

Another advantage is that the tolerances allowed for the outside diameter of the tube and the inside diameter of the socket are not critical, so long as the tube can easily be slid within the socket, the subsequent expansion of the tube automatically ensuring contact between the tube and the socket. In tests on the standpipe of the invention, internal pressures of 500 Ibs. per square inch have been imposed without the tube being forced out of the socket and without leakage of water past the joint formed between the tube and the socket. By having a cold joint, it is possible to utilise different materials for the tube and for the socket each particularly suited to the function it has to perform.

One embodiment of the invention is illustrated in the accompanying drawings which is a sectional side elevation of the lower part of a standpipe of the invention.

In the drawing a standpipe is formed from an aluminium tube 1 and a cast, e.g., diecast socket or base 2. The lower part of the socket 2 is provided with internal threads 3 to allow the standpipe to be secured to a hydrant. The upper part of the socket 2 is provided with an internal annular recess 4 and an internal taper 5, into contact with which the tube 1 is forced on expansion, e.g., by swaging of that part of the tube 1 lying within the socket. The intimate contact created between the tube and the socket is sufficient to prevent leakage of water even at very high pressure and the engagement between the tube and both the recess and the taper is more than sufficient to prevent the tube from being forced out of the socket again at very high water pressures.

1. A standpipe for use with hydrants comprising a tubular body, the lower end of which fits into a separately formed socket or base, part of the tube within the socket having been expanded into contact with the inner wall of the socket, which inner wall is provided with formations whereby following expansion of the said part of the tube, the tube and the socket become mechanically interlocked to form a leak-proof joint.

2. A standpipe as in Claim 1, wherein the tubular body and the separate socket or base are formed from different materials.

3. A standpipe as in Claim 1 or Claim 2, wherein the joint between the tubular body and the socket or base is cold formed.

4. A standpipe as in any of Claims 1 to 3, wherein the upper part of the socket or base is provided with an internal taper into contact with which the tubular body is forced on expansion.

5. A standpipe as in any one of Claims 1 to 4, wherein the upper part of the socket or base is provided with an internal recess into which part of the tubular body is forced on expansion.

6. A standpipe for use with hydrants substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Standpipes for hydrants This invention relates to standpipes for use with hydrants. It has been common practice for many years to provide strategically placed hydrants connected to a mains water supply, for the supply of water for, e.g., fire fitting purposes or for the controlled supply of water in times of water shortage. To allow for the dispensing of water from a hydrant it is equally common practice to provide a standpipe which is connected to the hydrant and has a normally closed valved outlet for connection, e.g., to a fire hose. Standpipes presently in use are normally constructed from a metal tube secured at its lower end to a metal socket or base, the socket having internal threads for connection to the hydrant.The metal tube is normally welded to the socket and which has the major disadvantage of reducing the mechanical properties of the tube which has led to the use of thicker walled tubing than would be otherwise necessary in an attempt to compensate for the reduced mechanical properties. The object of the present invention is to provide a standpipe for use with hydrants which avoids the need for a welded construction. According to the present invention, a standpipe for use with hydrants comprises a tubular body, the lower end of which fits into a separately formed socket or base, part of the tube within the socket having been expanded into contact with the inner wall of the socket, which inner wall is provided with formations whereby following expansion of the said part of the tube, the tube and the socket become mechanically interlocked to form a leak-proof joint. Thus, the joint between the tube and the socket is formed cold and consequently the mechanical properties of each part, particularly the tube, are not impaired. This has the direct effect of allowing the use of a tube wall thickness smaller than that of a comparable welded construction and yet of sufficient strength to fully meet the requirements of British Standard Number 336. Another advantage is that the tolerances allowed for the outside diameter of the tube and the inside diameter of the socket are not critical, so long as the tube can easily be slid within the socket, the subsequent expansion of the tube automatically ensuring contact between the tube and the socket. In tests on the standpipe of the invention, internal pressures of 500 Ibs. per square inch have been imposed without the tube being forced out of the socket and without leakage of water past the joint formed between the tube and the socket. By having a cold joint, it is possible to utilise different materials for the tube and for the socket each particularly suited to the function it has to perform. One embodiment of the invention is illustrated in the accompanying drawings which is a sectional side elevation of the lower part of a standpipe of the invention. In the drawing a standpipe is formed from an aluminium tube 1 and a cast, e.g., diecast socket or base 2. The lower part of the socket 2 is provided with internal threads 3 to allow the standpipe to be secured to a hydrant. The upper part of the socket 2 is provided with an internal annular recess 4 and an internal taper 5, into contact with which the tube 1 is forced on expansion, e.g., by swaging of that part of the tube 1 lying within the socket. The intimate contact created between the tube and the socket is sufficient to prevent leakage of water even at very high pressure and the engagement between the tube and both the recess and the taper is more than sufficient to prevent the tube from being forced out of the socket again at very high water pressures. CLAIMS

1. A standpipe for use with hydrants comprising a tubular body, the lower end of which fits into a separately formed socket or base, part of the tube within the socket having been expanded into contact with the inner wall of the socket, which inner wall is provided with formations whereby following expansion of the said part of the tube, the tube and the socket become mechanically interlocked to form a leak-proof joint.

2. A standpipe as in Claim 1, wherein the tubular body and the separate socket or base are formed from different materials.

3. A standpipe as in Claim 1 or Claim 2, wherein the joint between the tubular body and the socket or base is cold formed.

4. A standpipe as in any of Claims 1 to 3, wherein the upper part of the socket or base is provided with an internal taper into contact with which the tubular body is forced on expansion.

5. A standpipe as in any one of Claims 1 to 4, wherein the upper part of the socket or base is provided with an internal recess into which part of the tubular body is forced on expansion.

6. A standpipe for use with hydrants substantially as hereinbefore described with reference to the accompanying drawing.