GB2035493A - Swivel pipe union - Google Patents

Abstract

Swivel pipe union for connecting branch services to a supply main has a stem portion (10) forming a T connection with the main in use, and a banjo member (16) locating on a ferrule (12) of the stem portion defining a branch outlet (17) which can be angularly positioned anywhere about the stem. The ferrule is internally threaded to receive a male threaded top cam (18) for clamping the banjo member. The same internal thread may accommodate a screw-down valve plug (13) for shutting off the inlet, and the top cap may have a removable top plug (22) providing access for actuating the valve plug. <IMAGE>

Description

SPECIFICATION Swivel pipe union This invention relates to swivel pipe unions which are employed in a variety of situations, most commonly to effect a connection between a service main (usually underground) and a branch e.g. leading to a consumer to provide main water, gas or similar services.

The swivel pipe union with which the invention is concerned (hereinafter referred to as "a swivel pipe union of the kind described") comprises a hollow cylindrical stem portion having a male threaded end or other coupling formation adapted for connection to a service main or other supply duct to form a T connection therewith in use, a top cap having threaded engagement with the stem portion at the opposite end to said coupling formation, and a banjo member locating on the stem portion and provided with a branch outlet, sealing faces of the banjo member being clampingly engaged between flanges on the stem portion and top cap, and the stem portion being apertured to provide a flow passage from its interior to the branch outlet, the angular position of said outlet being adjustable about the stem portion axis.

A screw-down valve plug is commonly provided within the stem portion which can be engaged with a valve seating therein to shut off the main inlet, said plug being actuated by inserting a key or other tool through a coaxial aperture in the top cap provided with a removable closure.

One example of this kind of swivel pipe union is described in British Patent 686638 which shows an arrangement in which the top cap is internally threaded, clamping of the banjo outlet being effected by screwing said cap onto an upwardly projecting externally threaded part of the stem portion, resilient washers being provided between the opposing faces of the flanges and banjo member to provide a fluid tight seal while permitting slight misalignment to take place e.g. due to settlement of the ground around a buried pipe system.

The object of the invention is to provide a swivel pipe union of the kind described which is particularly compact, economical to produce in terms of material and manufacturing processes, and reliable and effective in use.

According to the invention there is provided a swivel pipe union of the kind described in which the top cap is provided with an externally threaded male formation for screw engagement with an interior thread of the stem portion for the clamping engagement of the banjo member.

Conveniently said cap male formation engages in an end part of the same threaded bore of the stem portion which receives a screw-down valve plug.

One embodiment of the invention is now more particularly described with reference to the accompanying drawing being a diagrammatic sectional view of a swivel pipe union.

A hollow cylindrical stem portion 10 has a coupling formation in the form of an externally threaded end portion 11 defining an inlet passage and which, in use, will be screwed to a service, e.g. water supply or gas main to form a T connection therewith. The other end part of stem portion 10 forms a ferrule 12 having an interior screw thread with which is engaged a screw-down valve plug 13 which can be engaged with a coacting seating 14 to shut off the inlet passage. Adjacent the seating the wall of the ferrule 12 has apertures 15 which valve plug 13 can be screwed clear of in its fully open position. A banjo member 16 fits onto ferrule 12 and can be rotated to any chosen angular position in relation thereto, it is provided with a female threaded branch outlet 17 to which a branch pipe can be connected, the direction of flow through the union being indicated by the arrows.

To provide a fluid-tight connection between banjo member 16 and stem portion 10 a top cap 18 is provided having a male threaded portion 19 for screw engagement in the end of ferrule 12 and a radial flange 20 which acts in opposition to a flange 21 on portion 10 to clamp the banjo member 16 therebetween, nitrile sealing washers or other gaskets formed from a resilient material being provided at the interfaces between said flanges and the banjo outlet to give a fluid tight seal which is flexible enough to accommodate slight misalignment occurring during assembly or subsequently, e.g. due to ground subsidence.

The centre of top cap 18 is provided with a threaded bore to receive a removable top plug 22 enabling access to be gained without dismantling the union for the insertion of a key or other tool which is engaged with a square socket or other drive formation in the top of valve plug 13 to rotate the latter.

Further resilient or other sealing washers or gaskets may be provided at the interface between cap 18 and plug 13 when the latter is fully open as an added precaution against leakage, and to seal top plug 22.

The above construction gives a considerable saving in weight and material (usually nonferrous metal) compared with known swivel pipe unions in which the top cap is internally threaded and is screwed onto a male threaded extension of the ferrule part of the stem portion which has to project a substantial distance beyond the banjo member for this purpose. There is also a considerable reduction in the dimensions of the union, particularly its length along the stem axis.

As well as the top cap being much smaller, the use of the invention enables the wall thickness of the ferrule to be substantially reduced as it does not have to to be internally and externally screw threaded, this reduction in wall thickness enables the dimensions of the banjo member to be reduced while still providing an adequate annular passage or gallery 23 to carry the fluid flow from apertures 15 to outlet 17. In order to accommodate the male threaded portion of top cap 18 the axial length of the valve plug 13 has had to be somewhat reduced, hence it is preferred that a greater number of smaller diameter apertures 15 is provided e.g. in a 141 inch nominal union eight 10 mm diameter apertures are provided instead of four 20 mm diameter apertures as was past practice.This enables plug 13 to have sufficient axial length to close off the apertures entirely before it reaches seating 14 so preventing leakage out of the bottom parts of the apertures and back through their top parts which would otherwise escape through top cap 18 during closure or opening with plug 22 removed. Machining operations are also reduced as a single threading operation provides the common internal thread for the valve plug and the top cap.

Unions incorporating the invention may be provided to suit a variety of requirements, for example the connections 11 and 17 can be male or female threaded with BSP pipe threads (unions to suit nominal sizes from 3 inch up to 2 inches or more may be provided); or formed to receive copper tube, polythene pipe, lead piping, capillary fittings, or bolted flanged connections. In some constructions the screw down valve may be dispensed with, in which case the top cap need not have a removable top plug.

Claims (6)

1. A swivel pipe union comprising a hollow cylindrical stem portion having a coupling formation at one end for connection to a supply duct to form a T connection therewith in use, a top cap having an externally threaded male formationfor screw-engagement with an interior thread of the stem portion at the opposite end to said coupling formation, and a banjo member locating on the stem portion and provided with a branch outlet, sealing faces on the banjo member being clampingly engaged between flanges on the stem portion and the top cap, and the stem portion being apertured for flow to pass from its interior to the branch outlet, the angular position of said outlet being adjustable about the stem portion axis.

2. A union as in Claim 1 including a screw-down valve plug within the stem portion which can be engaged with a valve seating therein to shut off a main inlet leading from said formation, the interior thread of the stem portion engaged by the top cap male formation being an end part of a threaded bore which also receives said plug.

3. A union as in Claim 2 wherein the top cap mounts a top plug which is removable for the insertion of a tool to actuate the valve plug.

4. A union as in Claim 2 or 3 wherein the axial length of the valve plug and arrangement of the aperturing of the stem portion are such that the plug closes off said aperturing before it engages said valve seating.

5. A union as in any one of the preceding claims including gasket of resilient material provided at the interfaces between said flanges and said sealing faces to give a fluidtight seal which will accommodate limited misalignment of the stem portion and banjo member.

6. A swivel pipe union substantially as hereinbefore described with reference to and as shown in the accompanying drawings.