GB2176877A

GB2176877A - Heated plug valves

Info

Publication number: GB2176877A
Application number: GB08615369A
Authority: GB
Inventors: Trevor Rose
Original assignee: CARTEM Ltd
Current assignee: CARTEM Ltd
Priority date: 1985-06-24
Filing date: 1986-06-24
Publication date: 1987-01-07
Also published as: GB8615369D0; GB8515977D0; GB2176877B

Abstract

In a cast-iron lubricated plug valve in which an apertured plug is rotatable about a vertical axis at right angles to the valve passage and maintained in place by a plug support (1) screwed into the bottom of the valve body, the plug support is drilled at right angles to the axis of the plug to form a blind bore (2) which receives a heating element for maintaining the valve in a heated condition to ensure through-flow of bitumen or other viscous material. <IMAGE>

Description

SPECIFICATION Heated plug valves This invention relates to cast-iron lubricated plug valves of the kind, hereinafter referred to as "the kind described', in which the apertured plug is rotatable about a substantially vertical axis extending at right angles to the valve passage and is maintained in place by a plug support screwed into the bottom of the valve body.

Such valves, being of relatively simple construction with interchangeable components which can be readily disconnected for cleaning, are suitable for use in controlling the supply and delivery of a wide variety of materials, some of which can flow only with difficulty. When used with bitumen, for instance, it is necessary to maintain the valve in a heated condition to ensure through-flow of material and it has been the practice to pass an electric current through a resistance wire wound around the outside of the valve body. Such a solution is not only clumsy but inefficient since a considerable proportion of the heat generated is dissipated in the surrounding air.

It is the object of the invention, therefore, to provide a more efficient way of heating a valve of the kind described to be used for bitumen and other difficultly flowable materials and to this end, according to the invention, the usual plug support is provided with a hollow chamber which extends most of the way across the support at right angles to the axis of the plug and opens at one side of the support to receive a heating element the leads of which extend through the open end of the chamber for connection to an external source of electric current.

One embodiment of the invention will be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a well-known form of lubricated plug valve; and Figure 2 is a side elevation, on a larger scale, of a plug support for the valve of Figure 1, constructed in accordance with the invention.

The standard form of cast-iron lubricated plug valve shown in Figure 1 comprises a valve body A having a valve passage B for the through-flow of material under the control of an apertured plug C which is rotatably mounted in a bore D intersecting the valve passage at right angles and maintained in place in the bore by a plug support 1 screwed into the bottom of the valve body and bearing upon the bottom of the plug through a coil spring E.

Figure 2 shows an improved form of plug support 1 in accordance with the invention, drilled at right angles to its axis to provide a blind bore 2 which is adapted to receive a standard form of heating element (not shown), the supply and return leads from which can pass through the open end 3 of the bore to an external current source.

This has been found to provide a considerably more efficient form of heating in which a much greater proportion of the heat generated in the heating element can pass upward into the interior of the valve body and act on the bitumen or other viscous material passing through the valve passage.

1. A lubricated plug valve of the kind described in which the plug support is provided with a hollow chamber which extends for most of the way across the support at right angles to the axis of the plug and opens at one side of the support to receive a heating element, the supply leads of which can extend through the open end of the chamber for connection to an external source of electric current.

2. A valve according to claim 1 in which said chamber is formed by drilling.

3. A lubricated plug valve according to claim 1 or 2 for controlling the flow of bitumen or other difficultly flowable material, provided with a heating element mounted in said hollow chamber and connected to a source of heating current.

4. A lubricated plug valve of the kind described, provided with a plug support substantially as described with reference to Figure 2 of the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Heated plug valves This invention relates to cast-iron lubricated plug valves of the kind, hereinafter referred to as "the kind described', in which the apertured plug is rotatable about a substantially vertical axis extending at right angles to the valve passage and is maintained in place by a plug support screwed into the bottom of the valve body. Such valves, being of relatively simple construction with interchangeable components which can be readily disconnected for cleaning, are suitable for use in controlling the supply and delivery of a wide variety of materials, some of which can flow only with difficulty. When used with bitumen, for instance, it is necessary to maintain the valve in a heated condition to ensure through-flow of material and it has been the practice to pass an electric current through a resistance wire wound around the outside of the valve body. Such a solution is not only clumsy but inefficient since a considerable proportion of the heat generated is dissipated in the surrounding air. It is the object of the invention, therefore, to provide a more efficient way of heating a valve of the kind described to be used for bitumen and other difficultly flowable materials and to this end, according to the invention, the usual plug support is provided with a hollow chamber which extends most of the way across the support at right angles to the axis of the plug and opens at one side of the support to receive a heating element the leads of which extend through the open end of the chamber for connection to an external source of electric current. One embodiment of the invention will be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a well-known form of lubricated plug valve; and Figure 2 is a side elevation, on a larger scale, of a plug support for the valve of Figure 1, constructed in accordance with the invention. The standard form of cast-iron lubricated plug valve shown in Figure 1 comprises a valve body A having a valve passage B for the through-flow of material under the control of an apertured plug C which is rotatably mounted in a bore D intersecting the valve passage at right angles and maintained in place in the bore by a plug support 1 screwed into the bottom of the valve body and bearing upon the bottom of the plug through a coil spring E. Figure 2 shows an improved form of plug support 1 in accordance with the invention, drilled at right angles to its axis to provide a blind bore 2 which is adapted to receive a standard form of heating element (not shown), the supply and return leads from which can pass through the open end 3 of the bore to an external current source. This has been found to provide a considerably more efficient form of heating in which a much greater proportion of the heat generated in the heating element can pass upward into the interior of the valve body and act on the bitumen or other viscous material passing through the valve passage. CLAIMS

2. A valve according to claim 1 in which said chamber is formed by drilling.