Title of Invention

A LUBRICATED PLUG VALVE

Abstract A lubricated plug valve comprising three parts, namely, a body, bonnet, and cover, the bonnet having a threaded bore for receiving the stem of the vaLve, the seal between the body and the bonnet joint being made by means of a gasket, with the stem engaging with the top of the plug of the valve; a gear flange provided for the bonnet to receive the gear box for the operation of the valve; the bonnet being provided with a packing injector connected to a groove receiving the stem packing compound injected through the packing injector to provide a primary stem seal; a spring disc and a bearing pad for the large end of the plug.
Full Text

This invention relates to a lubricated plug valve
The known lubricated plug valve consists of a body which has a flow passage for the inflow and outflow of the line media. The tapered plug inserted into the body is operated by a stem which is connected to the plug by an equalizer ring. The plug has a flow passage similar to the body. When the valve is operated, there are two possible positions for the plug. The plug port aligns with the body port in the open position, enabling the flow, and in the closed position; the plug port is perpendicular to the body port thus isolating the flow. In the conventional system, there is no distinct bonnet. The stem housing (or bonnet) is integral with the body casting.
The known valve incorporates an in built lubrication system with ducts in the body and sealant grooves on the plug. The valve sealant is injected inside the valve through a sealant injector fitting providing on the valve. The valve sealant flows through the grooves and spreads over the contact surfaces of the plug and body forming a lubrication film when the valve is operated. The lubrication film developed thus provides sealing of the flow media when the valve plug is in closed position. The rotational movement of the plug inside the body also leads to friction and hence the operating torque on the valve stem. The sealant injected into the system reduces friction and makes the valve operation easier.

The disadvantages of the known valve are as follows:
The small end of the body taper bore is inaccessible for machining. It is difficult to clean the sand inclusions accumulated at the small end of the body taper.
The entire body size and weight to be taken in to consideration for small end machining operations like threading, gear flange machining, gear flange drilling and tapping, packing and sealant injector hole machining operations.
Due to the small end of the body taper, it is difficult to reach and weld when the overlay welding like satellite and inconel are involved.
More weight is concentrated on a single casting.
On the other hand the advantages of the valve proposed herein are:
The body construction becomes modular and simpler to handle the components and machine.
The small end of the body taper is easily accessible and the machining is much easier than the existing system.
The body weight is split and distributed between the body and the bonnet.

The thread machining is restricted to the bonnet which is a much smaller part and hence could be machined conveniently with more accuracy.
The body casting weight is reduced and hence easier to handle and machine the body taper.
The design is advantageous especially when the body overlays with stellite and Inconel weld overlays are called for.
Equalizer ring can be eliminated by making the plug stem directly engaged with the plug.
The lubricated plug valve, according to this invention, comprises three parts, namely, a body, bonnet, and cover, the bonnet having a threaded bore for receiving the stem of the valve, the seal between the body and the bonnet joint being made by means of a gasket, with the stem engaging with the top of the plug of the valve; a gear flange provided for the bonnet to receive the gear box for the operation of the valve; the bonnet being provided with a packing injector connected to a groove receiving the stem packing compound injected through the packing injector to provide a primary stem seal; a spring disc and a bearing pad for the large end of the plug, while the large end of the body taper has a cover flange which is tapped to receive the cover.

This invention will now be described with reference to the accompanying drawings which illustrate in the single Figure therein one of possible embodiments of the invention, by way of example and not by way of limitation.
The lubricated plug valve proposed herein comprises three parts, namely, a body (1), bonnet (2) and cover (3). The bonnet (2) has a threaded bore for receiving the stem (4) of the valve and is bolted to the body small end. The sealing between the body and the bonnet (2) is made by means of a gasket (5). The stem (4) engages with the top of the plug (6) of the valve. The bonnet (2) has a gear flange (7) to receive the gear box (8) for the operation of the valve. The bonnet is provided with a packing injector (9) connected to a groove (10) receiving the stem packing compound injected through the packing injector to provide a primary stem seal. The large end of the plug has support components which are a spring disc (11) and a bearing pad (12).
The cover (3) is bolted to the body (1) by means of studs (13) and nut (14).
The plug loading screw (15) is assembled inside the threaded hole in the cover (3). The sealing between the body (1) and the cover (3) joint is made by means of gasket (16). The diaphragm (17) is supported between the body (1) and the cover (3) joint. The plug loading screw (15) supports and loads the plug (6).

We Claim:
1. A lubricated plug valve comprising three parts, namely, a body, bonnet, and cover, the bonnet having a threaded bore for receiving the stem of the valve, the seal between the body and the bonnet joint being made by means of a gasket, with the stem engaging with the top of the plug of the valve; a gear flange provided for the bonnet to receive the gear box for the operation of the valve; the bonnet being provided with a packing injector connected to a groove receiving the stem packing compound injected through the packing injector to provide a primary stem seal; a spring disc and a bearing pad for the large end of the plug.
2. A lubricated plug valve as claimed in Claim 1 where in the cover is bolted to the body by means of studs and nuts.
3. A lubricated plug valve as claimed in Claim 1 or Claim 2 where in the plug loading screw is located inside a threaded hole in the cover.
4. A lubricated plug valve as claimed in Claim 1 or Claim 2 or Claim 3 where in the bonnet is welded to the body.
5. A lubricated plug valve as claimed in any one of the preceding claims where in the primary stem seal comprise die molded packing rings housed and compressed inside a stuffing box provided in the bonnet.

6. A lubricated plug valve as claimed in any one of the preceding claims where in
the sealing between the body and cover joint is made by means of a gasket
7. A lubricated plug valve as claimed in any one of the preceding Claims wherein
8. the diaphragm is supported between the body and cover joint.
9. A lubricated plug valve as claimed in any one of the preceding Claims wherein
10. the diaphragm is supported between the body and the cover joint.
9. A lubricated plug valve as claimed in any one of the preceding Claims wherein
the plug loading screw supports and loads the plug.
10. A lubricated plug valve substantially as herein described with reference to, and
as illustrated in, the accompanying drawings.
Dated this the 29th day January 2007


Documents:

187-che-2007 claims.pdf

187-che-2007 correspondance others.pdf

187-che-2007 correspondence-others.pdf

187-che-2007 form-3.pdf

187-che-2007-abstract.pdf

187-che-2007-claims.pdf

187-che-2007-correspondnece-others.pdf

187-che-2007-description(complete).pdf

187-che-2007-drawings.pdf

187-che-2007-form 1.pdf

187-che-2007-form 18.pdf

187-che-2007-form 26.pdf


Patent Number 241960
Indian Patent Application Number 187/CHE/2007
PG Journal Number 32/2010
Publication Date 06-Aug-2010
Grant Date 03-Aug-2010
Date of Filing 29-Jan-2007
Name of Patentee AUDCO INDIA LIMITED
Applicant Address AUDCO INDIA LIMITED, MOUNT POONAMALEE ROAD, MANAPAKKAM, CHENNAI 600089
Inventors:
# Inventor's Name Inventor's Address
1 RAMAKRISHNAN MURUGANANTHAM AUDCO INDIA LIMITED, MOUNT POONAMALEE ROAD, MANAPAKKAM, CHENNAI 600089
2 NARAYANAN VASUDEVAN AUDCO INDIA LIMITED, MOUNT POONAMALEE ROAD, MANAPAKKAM, CHENNAI 600089
PCT International Classification Number F16K5/22
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA