GB2318170A - Two part valve stem - Google Patents

Two part valve stem Download PDF

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Publication number
GB2318170A
GB2318170A GB9621150A GB9621150A GB2318170A GB 2318170 A GB2318170 A GB 2318170A GB 9621150 A GB9621150 A GB 9621150A GB 9621150 A GB9621150 A GB 9621150A GB 2318170 A GB2318170 A GB 2318170A
Authority
GB
United Kingdom
Prior art keywords
stem
ball valve
valve
split
ball
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9621150A
Other versions
GB9621150D0 (en
Inventor
Thomas Laing
Andrew Paul Laing
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to GB9621150A priority Critical patent/GB2318170A/en
Publication of GB9621150D0 publication Critical patent/GB9621150D0/en
Publication of GB2318170A publication Critical patent/GB2318170A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K5/00—Plug valves; Taps or cocks comprising only cut-off apparatus having at least one of the sealing faces shaped as a more or less complete surface of a solid of revolution, the opening and closing movement being predominantly rotary
    • F16K5/06—Plug valves; Taps or cocks comprising only cut-off apparatus having at least one of the sealing faces shaped as a more or less complete surface of a solid of revolution, the opening and closing movement being predominantly rotary with plugs having spherical surfaces; Packings therefor
    • F16K5/0647—Spindles or actuating means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K41/00—Spindle sealings

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Taps Or Cocks (AREA)

Abstract

A modified ball valve stem is divided into two parts 1,2 for retro-fitting to a existing valve (as fig 1). The modified stem has additional seals 4 and 8 around collar 3.

Description

MODIFiCAT1ON TO BALL VALVE.
This invention relates to a ball valve split stem which has a two fold advantage.
It is well known that a constant source of fugitive emmissions to the atmosphere is from the essential axial clearance between the one piece stem and the gland packing in a ball valve.
Due to mounting legislation to eliminate pollution including fugitive emmissions from valves to be included in the clean air act, the emmissions of pollutants including " volatile organic compounds " ( voc ) must be controlled to reduce the amount of harmful ground level particulates and thereby improve the quality of the environment.
Advantage 1, according to the present invention, is that the ball valve axial stem clearance will not pass pollutants into the atmosphere, by the introduction of a double constant radial interface, using a two component split stem, the upper stem complete with a sealing collar, the lower stem incorporating the anti blowsut proof collar, as specified in accordance with BS 5351.
Advantage 2, according to the present invention, simplifies the assembly within the ball valve body of the upper and lower stem, by insertion of the upper stem through the gland from the outside, whilst the lower stem is inserted through the inside of the valve body, with the upper and lower stems connecting by a male I female, rebate I protrusion, handed to suit the ball valve manufacturers production facilities, (i.e. rebate I protrusion can be reversed from upper to lower stems ).
A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig .i. shows a typical single stem situation.
Fig .2. illustrates the physical situation of the split stem.
Fig .3. shows in perspective the split stem ( male I female alternative).
Referring to Fig .1. it is apparent that there is a leak path due to the inbuilt axial clearances, by design, which will enlarge when wear takes place by operation of the valve.
Referring to Fig .2. in order to eliminate completely the leak path, the present invention includes in the upper stem 1 a circular gland seal collar 3 which provides a double radial no clearance interface, with the primary stem seal 4 between the gland seal collar 3 and the valve body 9.
In order to operate the valve there is a connection made between the upper stem 1 and the lower stem 2 by way of a male I female rebate and protrusion, which can be reversed i.e. lower stem ( male ) upper stem ( female ), lower stem ( female ) upper stem ( male ) preference being the choice of the valve manufacturer.
The lower stem 2 in accordance with the requirements of british standard BS 5351 - Steel ball valves for the petroleum, petrochemical and allied industries, incorporating the anti blowsut proof collar 5.
The whole of the assembly of the present invention can be put together without any modification to the existing valve body, the necessary pressure on the radial interfaces of the primary double stem seal 4 and the secondary stem seal 8 being accomplished by way of the pressure loading gland female 6 acting through the live load stem seal springs 7, in order to obtain a zero emmission from the valve gland.

Claims (6)

CLAIMS.
1. The modification to a ball valve stem, using a split stem, with an incorporated radial sealing collar in the upper stem, prevents fugitive emmissions from the valve stem gland, when failure of the valve seat rings has occured.
2. A ball valve split stem as claimed in Claim 1. means that simplified valve assembly during manufacture is possible without any modifications to the valve body.
3. A ball valve split stem as claimed in Claim 1. & Claim 2. enables the split stem to be manufactured from different metals, thus reducing the manufacturing costs, i.e. lower stem metal will equate to the metal of the valve body and ball, whereas the upper stem can be made from a lower specification metal.
4. A ball valve split stem, with an upper stem radial collar as claimed in Claim 1. will minimise product loss and increase profitability to the process manufacturing company.
5. A ball valve split stem as claimed in Claim 1. & Claim 4. will prevent fugitive emmissions into the atmosphere subsequently improving the quality of the environment.
6. A ball valve split stem substantially described herein with reference to Figures 1 - 3 of the accompanying drawings.
GB9621150A 1996-10-10 1996-10-10 Two part valve stem Withdrawn GB2318170A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9621150A GB2318170A (en) 1996-10-10 1996-10-10 Two part valve stem

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9621150A GB2318170A (en) 1996-10-10 1996-10-10 Two part valve stem

Publications (2)

Publication Number Publication Date
GB9621150D0 GB9621150D0 (en) 1996-11-27
GB2318170A true GB2318170A (en) 1998-04-15

Family

ID=10801226

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9621150A Withdrawn GB2318170A (en) 1996-10-10 1996-10-10 Two part valve stem

Country Status (1)

Country Link
GB (1) GB2318170A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5170991A (en) * 1990-07-16 1992-12-15 Heil John S Valve seal apparatus

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5170991A (en) * 1990-07-16 1992-12-15 Heil John S Valve seal apparatus

Also Published As

Publication number Publication date
GB9621150D0 (en) 1996-11-27

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)