AU593355B2

AU593355B2 - Gas cock for a burner

Info

Publication number: AU593355B2
Application number: AU74084/87A
Authority: AU
Inventors: Heinrich Somer
Original assignee: Paul Isphording Metallwerke GmbH and Co KG
Current assignee: Paul Isphording Metallwerke GmbH and Co KG
Priority date: 1987-06-10
Filing date: 1987-06-10
Publication date: 1990-02-08
Anticipated expiration: 2007-06-10
Also published as: AU7408487A

Description

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AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECEFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Thisd Lc ed: amend Sectior Complete Specification-Lodged: Pritin Accepted: Lapsed: Published: Form Priority: Related Art: 0

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59 33 TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applic/nt:

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PAUL ISPHORDING METALLWERKE GmbH and CO. KG FINNENTROPER STRASSE 16 5952 ATTENDORN,

WESTFALEN

WEST GERMANY CLEMENT HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

S Actual Inventor: Address for Service:

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Complete Specification for the invention entitled: GAS COCK FOR A BURNER The following statement is a full description of this invention including the best method of performing it known to me:- 1

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,i 2 *9 9«9 4 o* 0 *0 GAS COCK FOR A BURNER GAS COCK FOR A BURNER This invention relates to a gas cock for controlling gas flow to a burner. Conventional gas cocks for the use with gas burners are provided with two fixed gas ways drilled through the control plug within the cock, and which meter the te volume of gas flowing through them. The gas ways can also be 10 replaced by jets screwed within the gas ways provided in the associated gas lines.

Gas cocks of this type have a maximum gas flow position (Full On) and a minimum gas fldr position (Turndown).

Bqth control settings are obtained by turning a control knob 1 connected to a gas cock spindle which turns the plug inside r i 3 the body o4 the cock through limited angles so as to connect the gas ways in the plug with the gas inlet in the body of the gas cock.

There are also gas cocks which have intermediate positions between "full on" and "turndown" and which, for this purpose, have a further gas way for each intermediate position or alternatively a slot starting from the gas way which provides maximum gas flow.

However, there is an increasing tendency to design for a continuously regulated characteristic gas flow between "full on" and "turndown". There are also gas cocks which have a conical slot in the plug which starts at the "full on" position and runs in the direction of the "turndown" position.

There is, however, a production problem with this type of gas cock as it is difficult to produce this slot within the very narrow limits of tolerance which would be necessary to ensure that the gas volume is reduced continuously and uniformly between "full on" and "turndown". There is also the need to have the plug lubricated inside the housing to ensure trouble 20 free operation for many years. Frequently the gas cocks are ;installed very close to the burners so that the gas cock may ttI be subjected to temperatures up to 150 0 C. At these comparatively high temperatures the lubricant tends to liquefy K. and may very easily partially or completely block the conical 25 control slot. Thus the intended continuous reduction of the gas flow is no longer achieved.

aa c It is an object of the present invention to provide a gas cock which will ensure the continuous reduction of the gas flow ove the entire predetermined control, limits between the "full on" and "turndown" positions and maintain this after H a prolonged period of use without having its regulating characteristic affected by the lubricant which may be liqueficd at high temperature. In addition it is an object of the inventiolt to provide a gas cock which will permit the production of its parts without requiring rarrower or closer manufacturing tolerances.

4 In accordance with the invention there is provided a control plug for a gas cock, said plug including a partially radially extending main passage therethrough communicating with a first slot extending partially around the circumference of said plug, and a second slot, independent of said main passage and said first slot, and also extending partially around said plug, wherein said second slot is arranged to allow, in a control position of said first slot an additional supply of gas to provide a flow of gas around said plug to ensure there is always a predetermined minimum flow of gas between the inlet and the outlet of an associated gas cock housing when said plug is in a control position or in a turndown position.

With the present invention it is possible to use manufacturing tolerances presently applicable in the production of gas cocks as the progressive control function is obtained by the co-operation of at least two independently arranged slots and simultaneously ensures the supply of gas at the turndown position.

One preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view through the gas cock of the preferred embodiment with the control plug in a closed position; Figure 2 is a view similar to Figure 1 with the control plug in the full on position; Figure 3 is a view similar to Figure 1 with the control plug in an alternative control position; and control plug in the turndown position, With reference to Figure 1, the gas Cock comprises a gas cock housing 1 with a gas inlet passage la and a gas *"cs outlet passage lb.

35' Between the gas inlet passage la and the gas outlet passage Ib there is the control plug 2 having a main gas passage 4, and a partially circumferentially extending slot which provides the progressive control. An additional y L 1 ,0 independent of slot 5 is also provided for the supply of gas for the "turndown" control position and which is determined by the metering passage 3a forming part of a control valve 3.

With the control plug 2 in the position shown in Figure 1 the gas cock is in the closed position in which gas at the gas inlet passage la of the gas cock housing 1 is prevented from flowing through the cock by the conical body of gas control plug 2.

Figure 2 of the drawings shows the same gas cock as Figure 1, but in the "full on" position of the control plug 2, wherein gas flows through the main gas passage 4 of the control plugland through an axial passage 2a communicating therewith to the gas outletklb from the gas cock housing 1 and onto an associated gas burner.

Figure 3 of the drawings shows the same gas cock as Figures 1 and 2, but with the control plug 2 intermediate control position. With the control plug 2 in the position of Figure2', gas flows from the gas inlet passage la and by way *mo of the partially circumferentially extending wedge shaped slot 20 5 to the main gas passage 4, and also by way of the partially rsaQ circumferentially extending slot 6 to and through a connecting Spassage 7 to the metering passage 3a of the control valve 3 and then by way of a further connecting passage 8 to the gas :',outlet passage lb from the gas cock housing 1 and onto the t ft 25 associated gas burner.

Figure 4 of the drawings shows the same gas cock as Figures 1, 2 and 3, but with the control plug 2 in the "turndown" position. With the control plug 2 in the position of Figure 4 gas flows through the gas inlet passage la and, by way of only slot 6 around the control plug 2, to and through t ,e connecting passage 7 to the metering passage 3a of the Acontrol valve 3 and then through the further connecting passage 8 to the gas outlet passage lb from the gas cock housing 1 and onto the associated burner.

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Claims

6- THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1i. A control plug for a gas cock, said plug including a partially radially extending main passage therethrough communicating with a first slot extending partially around the circumference of said plug, and a second slot, independent of said main passage and said first slot, and also extending partially around said plug, wherein said second slot is arranged to allow, in a control position of said first slot an additional supply of gas to provide a flow of gas around said plug to ensure there is always a predetermined minimum flow of gas between the inlet and the outlet of an associated gas cock housing when said plug is in a control position or in a turndown position. 2. A control plug as claimed in claim 1, wherein said main passage and communicating first slot are arranged to allow a maximum flow of gas between the inlet and the outlet of an associated gas cock housing when the plug is in a fully open position. 3. A control plug as claimed in claim 1 or 2, wherein said first and second slots are arranged to allow a variable S. intermediate gas flow rate between the inlet and the outlet of an associated gas cock housing when said plug is in a control position intermediate a fully open and a turndown *position. t 4. A control plug as claimed in any of the preceding claims, wherein said main passage with communicating first slot and the second slot are all arranged so that in a close position of said plug none allow gas flow between the inlet and the outlet of an associated gas cock housing, A control plug as claimed in any one of the preceding claims, wherein said second slot is arranged to j IJ 'allow a flow of gas between the inlet and the outlet of an associated gas cock housing via a by-pass passage through the associated gas cock body. 6. A gas cock including a gas cock housing with an inlet and an outlet and a chamber between said inlet and said outlet, said chamber receiving a control plug as claimed in any of claims 1 to
7. A gas cock as claimed in claim 6, wherein said gas cock oUsing includes a by-pass passage from said chamber to s I outlet. 'said 0 Ic i ^j
8. A gas cock as claimed in claim 7, wherein said Sby-pass passage includes a metering valve.
9. A control plug for a gas cock substantially as hereinbefore described with reference to the accompanying drawings. A gas cock substantially as hereinbefore described with reference to the accompanying drawings. DATED THIS 10th Day of JUN.E, 1987 PAUL ISPHORDING METALLWERKE GmbH and CO. KG. By Its Patent Attorneys; CLEMENT HACK CO. a Fellows Institute of Patents Attorneys of Australia A IT