US2856951A

US2856951A - Gas valves for use in flue between a gas producer and a consuming unit for the gas, e. g., a furnace

Info

Publication number: US2856951A
Authority: US
Inventors: Eric A Greenway; James J Whiteheart
Original assignee: Pilkington Brothers Ltd
Current assignee: Pilkington Group Ltd
Priority date: 1954-07-21
Filing date: 1955-07-14
Publication date: 1958-10-21
Anticipated expiration: 1975-10-21

Description

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United States Patent GAS VALVES FOR USE IN FLUE BETWEEN A GAS PRODUCER AND A CONSUMING UNIT FOR THE GAS, e. g., A FURNACE Eric. A. Greenway, Huyton, and James J. Whiteheart, Liverpool, England; assignors to Pilkington Brothers Limited, Liverpool, England, a British company This invention relates togas valves for use in the ue between a gas producer and a consuming unit for the gasA e. g. a furnace.

Valves of this description are usually located in the `ilue at the point where the latter turns at right angles from the vertical to the horizontal and are made of cast iron in circular form. They have a bevelled seating edge,

which seals against a corresponding bevelled seating in a 1 cast iron plate, in similar fashion to a poppet valve in an internal combustion engine. Sealing of the valve is effected by accurate metal-to-metal contact, but the relatively high temperature of producer gas in the line tends to cause more or less warping of the valve parts, and in consequence a leakage of gas would take place between the valve and its seating if it were not for the fact that the valve becomes sealed by tar deposited by the gas.

This condition, however, is very inconvenient when it becomes necessary to operate the valve, because the tar may causeit to adhere to its seating so firmly that great force is needed to lift it, and it is also very difiicultto make the valve seat properly when it is `again closed. Moreover, such a valve often begins to leak in spite of the deposited tar, and when this happens the work of sealing the valve has to be done in an atmosphere of gas, which is dangerous and may give rise to accidents.

It is the main object of the present invention to provide a gas valve of improved design in which the disadvantages aforesaid are avoided.

A further object of the invention is to provide a gas valve which is simple to produce and at the same time is particularly effective in operation, and remains in good working condition unefected by tar and other matter deposited by the gas.

According to the invention, a gasvalve for location in a ue between the gas producer and a consuming unit for the gas e. g. a furnace where the gas ow is made to vary its direction from vertical to horizontal comprises a liftable and lowerable hood open on the underside towards the vertical passage of the ilue, the wall of said hood towards' a horizontal passage or passages of the ue being cut away to form an aperture providing communication between the interior of the valve and the said horizontal passage or passages in the lifted position of the hood, and a deep narrow open trough in association with the Vertical iiue passage to form a liquid seal for the hood wall in the lowered position thereof.

Preferably the hood is of polygonal e. g. rectangular form in plan view, one or more walls being cut away in a form providing predetermined characteristics in respect of the cross-sectional area of ea-ch aperture in relat tion to the extent of movement of the hood, the cutaway portions providing communication with corresponding horizontal flues and the vertical ilue.

Means may be provided for effecting a continuous supply of sealing liquid to the said trough, together with an overflow pipe for discharging surplus liquid from the trough. The overflow pipe itself may be provided with its own liquid sealing trough externallycf the valve.

The valve may be operated by a valve stem extending through the wall of the iiue and connected to the top of the hood, a deep narrow open trough adapted to form a 'liquid seal being secured to the top of the flue surrounding the said stem and a concentric skirt secured to an upper part of the said stem being arranged to dip into the said trough. The trough surrounding the stern may be furnished with means for effecting a continuous supply and discharge of the sealing liquid to and from the trough. v

The concentric skirt securedto the valve steml may be graduated in accordance with thefcharacteristics of the opening cut away in the wall of the hood so that it indicates the extent of opening the valve. This indication in conjunction with indications of the gas pressures in the inlet and outlet passages to each side of the valve, which pressures may be indicated by suitable manometers connected to those passages, provides va measure of the rate of flow of gas through the valve, which then serves as a variable-orifice metering device.

In order that the invention may be more clearly understood, a preferred embodiment thereof will now be ydescribed, by way of example, with reference to the accompanying diagrammatic drawing, which shows in perspective View, partly broken away, a gas valve'according to the invention controllingv gas to one horizontal outlet flue.

The drawing illustrates the conduit between a gas producer and a furnace at the point where it turns at right angles from vertical to horizontal, the vertical passage being indicated at 1 and the horizontal passage at 2. The conduit, which may consist of steel, is preferably lined with a heat-insulating machine such as refractory brick as at 3, and in addition the steel casing may alsovbe set in brickwork (not shown).

The valve itself comprises a hood 4 including a top portion 5 and four depending peripheral wall parts, the said hood being open at the bottom towards the vertical passage of the flue. The side wall part 6 of the hood facing the horizontal passage 2 is cut away except for a portion left deep enough to serve as a sealing lip.

About the vertical passage 1l of the flue there is provided a trough 7 connected tothe outer wall of the ilue along the bottom, the inner face of the trough being formed by the outer wall of the flue. This rectangular trough is adapted to receive water and to act as a water seal, so that when the hood is lowered so that all four walls are immersed in the water contained in the trough 7 a completely gastight closure is obtained.

The valve is opened by` lifting it by means of a stem 8, which is pinned to angle-iron stiffeners 9 welded to the top 5 of the hood, the sealing lip formed by the wall part 6 thereby being lifted out `of the water in the `sealing trough 7.

Torpreserve balance in the hood a'mass (not shown) may bepattached either on the inside of the wall part 6 or of the top portion 5, equal in weight to the amount of metal missing from that side of the hood in making the wall part 6 of less depth than the three other wall parts of the hood. l

When the valve is open, gas has access to the space between the top 5 of the hood and the upper wall of the flue, so that a seal mustv be provided around the stem 8 where it passes through the top of the flue. This takes the form of a deep water-sealing trough comprising two concentric tubes 10 and 11, preferably of steel, welded to a base ange 12 secured to the top of the flue, and a concentric skirt 13 secured to the stem at 14 and dipping v into the trough 10, 11, the said skirt having a diameter about midway between the diameters of the two tubes forming the trough 10,' 11. v To replace water lost by evaporation and to carry away any deposits of tar or soot on the exposed water surfaces a continuous supply of wateruis provided to the trough 7 at 15 and the trough 10, 11 at 16. The Water enters at the bottom of eachtrough, and passes out at the top of each trough throughoverowrpipes, such as the pipe 17 leading from the trough 7 and. the pipe 18 leading from the trough 10, 11. In thisway aconstant level of-water is maintained in `each trough.

The continuous-flow of water ,through thel sealing troughsr as described is of considerableadvantage in .preventing overheating of the workingparts, i. e., the hood,

valve stern and'so forth, and contributes greatly towards keeping the valve in good condition.

In case an accumulation of siltin the bottom of ,trough 7 occurs, doors (not shown) may be provided at the bottom 0f the troughe. g. at opposite corners to allow takes to be inserted to remove the .silt as will be readily understood, a similar door may be fitted to the trough 19.

As the overflow from the trough 7 comes from a space which contains'gas when the valve is open, the overow pipe 17 is provided with its own water Iseal in the form of a small tank 19, into which the pipe 17 dips. The depth to which the pipe 17dips below water level in the tank 19 must be at least as-.great as the maximum water gauge height of the pressure of the gas in the horizontal flue 2. The small tank 19 is provided with an overilow pipe 20.

It would of course be possible to provide an external seal to the overflow 17 by making 'the pipe 17 in the form of a U-tube. However, this tube might become blocked by tan-soot and the like deposited from the gas. In the small open tank 19 these deposits come to the surface of the water and are carried away by the overow.

The valve may be used so that gas passes through it in either direction. Usually the arrangement is such that gas flows up through a vertical passage and out of the valve into a horizontal passage of the ue. The crosssectional dimensions of the flue may vary according to requirements and may range, for example, between one foot square and six foot square. However, the invention is in no way limitedto a particular size.

The cut-away wall part-6 of the hood may be of any predetermined form for giving desired characteristics to the cross-sectional area of the valve aperture in relation to the extent of movement of the hood. For example, if it were desired that the valve opening should be linearly proportional to the distance through which the hood is lifted, a plain rectangularV aperture can be provided as shown. If on the other hand the aperture were required to change more rapidly than in linear proportion to the vertical movement of the hood, the aperture could take the form of, say, an inverted V. If a small denite opening Were-required justshort of total closure, this could be provided vby furnishingia notch of appropriatewidth and dept-h inthe top Vedgeofa rectangular aperture or, in

. the case of an invertedV V; opening, by the provision of a top parallel portion of suitable relativelynarrow width instead of a sharp apex. p

Hyg-graduating the tube v1li-attached to the valve stern 8 in .accordance with theshape ofthe opening in rthe wall` 6 of the valve hood j4the valve may be used, in conjunction with pressure,'indicating` devices, such as manometers connected to the inlet and outlet tlues, as a variable orice for metering theV gas passing-through it.

The normal workingpressure of-producer 'gas is yabout 2" water gauge. Itmay,however, rise to about l2" water gauge or more,2 andthe minimum depth of each seal should therefore be at least equal to this maximum water gauge height. The hoodconstruction may be duplicated by a verti- .the flues to accommodate the;divi c lingfwall. lhus, outer hood walls e. g. opposite walls may `be, cut-,away to-con trol ow from either` vertical `flue to Val horizontal passage or to independent passages, and the flues may be made to -communicatethrough the saiddividing wall, if the latter is of lesser height than the wall parts 6 of such structure. Alternatively two hoods may be arranged back to back in a vertical lue to beeindpendently movable, in which Vcase thetroughj isprovided with a medial trough, making the lwaterseal for the hoods walls of Figure 8 form, instead of purely rectangular form hereinbefore described.

In the foregoing description reference has generally been made to' gasiflow from the vertical flue to a furnace but clearly the hood vconstruction can be used to regulate a reverse flow through the hood into the flue or iiues, as .the case may be,'so that where a duplicate hood structure is employed the reverse ow through the hood may be into either'or both of the vertical ues.

By the provision of the-refractoryy linings to the troughs in the ues there is substantially no loss of heat from the vliue gases through the valve.

By the lpresent invention a seal is obtained which maint-ains a perfect seal against the ow of gasesthrough` the flue, in contradistinction to valve constructions hitherto employed in which the seating of the valve may be impaired by depositsy from the ue gases or as a result of distortion of the valve or its seating due to the temperature of the gases passed by the valve.

-Experiments have demonstrated that the valve structure-hereinbefore described andillustrated may be successfully used as a metering device to determine they rate of ow of gasthrough it; and that it is especially superior to the ordinaryforrn of valve in providing'immediate positive closure when it is necessary to `switch-flue connections, as, for instance, when changingv rom=one gas-producer toA another for the supply to a glass melting furnace or furnaces. There is no mechanical resistance to closure, and the graduated stem shows when the valve is in the closed position, So that one knows for certain that there is then a perfect seal thus obviating the usual practice when using-ordinary valves of going into the valve chamber to` inspect the working of the valve, and where necess-ary to tamp clay in to stop leaks.

We claim: I

l. A gas valve and seal therefor to controlrflow of gas between twopassageways, one of which is substantially vertical, the other being substantially horizontal, comprising a valve body in the form of a hood adapted to be supported for vertical movement in the vertical passageway and across the end of the horizontal passageway into open position in which the ilow of the gas between the two passageways is permitted andl into closed position in which the flow of the gas between the two passageways is blocked, said valve body having a top wall in exposed position to be in the path of gas iiow between said passageways in installed position of the gas valve, and a peripheral wall depending from said top wall and forming a unit with said top wall movable in unison therewith into open and closed positions, the part of said peripheral wallwhich is nearest the horizontal passageway in installed position of the gas valve, being shorter than other parts of said peripheral wall to form an opening in said peripheral wall between saidy other longer parts tlankingsaidshorter part for the ilow 0f gas between said passageways in open position of said valve, said shorter wall part being suflicientlylong to t blockpassage ofgas `between Said passageways inclosed position of the valve, and a seal comprising a trough having the configuration of the 4hood and adapted to contain liquid for a liquid seal, said trough being in position to receive in the liquid therein the entire lower section of the wall including that of the shorter part to seal said valve inl closed position of the valve and being in position to receive in the liquid therein the-lower section of the longerI wall parts in open position ofi-said valve,'in theV operation of the gas lvalve and seal', all the longerparts of the peripheralwall being immersed-within' the Vliquidin thertrough throughout thecomplete range of movement of the hood from a fully closed to a maximum open position of the valve.

2. An apparatus for condu'; ting gas and for controlling its ow, comprising a conduit for the flow of gases comprising a substantially vertical passageway and a substantially horizontal passageway, and a valve and seal therefor for controlling ow between said passageways, comprising a valve body in the form of a hood supported for vertical movement in the vertical passageway and across the end of the horizontal passageway into open position in which the ow of the gas between the two passageways is permitted and into closed position in which the ow of the gas between the two passageways is blocked, said valve body having a top wall in exposed position to be in the path of gas flow between said passageways in open position of said valve, and a peripheral wall depending from said top wall and forming a unit with said top wall movable in' unison therewith into open and closed positions, the part of said peripheral wall which is nearest the horizontal passageway being yshorter than other parts of said peripheral wall to form an opening in said peripheral wall between said other longer parts flanking said shorter part for the ow of gas between said passageways in open position of said valve, said shorter wall part bein'g sufficiently long to block passage of gas between said passageways in closed position of the valve, and a seal comprising a trough around the passage dened by said vertical passageway having the configuration of the hood and adapted to contain liquid for a liquid seal, said trough being in position to receive the en'tire lower section of the wall including that of the shorter part to vseal said valve in closed position of the valve and being in position to receive in the liquid therein the lower section of the longer wall parts in open position of said valve, in the operation of the valve, all the longer parts of the peripheral wall bein'g immersed within the liquid in the trough throughout the complete range of movement of the hood from a fully closed to a maximum open position of the valve.

3. The combination according to claim 1, comprising a valve stem connected to said top wall for operating said valve into open and closed position and means for holding sealing liquid in contact with said ystem and for forming with the sealing liquid a seal to prevent leakage of gas from the vertical passageway along said stem.

4. The combination according to claim 2, comprising a valve `stern connected to said `top wall and passing through a top wall in said vertical passageway for operating said valve into open and closed positions, and a seal for said stem to prevent leakage of gas from the vertical passageway along said stem, and comprising a trough secured to the top wall of the vertical passageway and surrounding said stem, a concentric skirt secured to an upper part of said stern an'd dipping into said trough, and means for effecting a constant supply and discharge of the sealing liquid to and from the last mentioned trough.

5. A hollow gas valve and seal therefor, the valve comprising a body in the form of a hood open at the bottom and including a peripheral wall, one part of said wall being shorter than the other parts of said wall, the seal comprisin'g a trough below the top wall of said hood in registry with said wall and having the general configuration of the hood, said trough being adapted to hold liquid and to receive said peripheral wall to form a liquid seal therefor when the hood is lowered in valve closed position to block flow of gas through the hood and out from under said wall, the trough being of a depth and the longer parts of the wall being of a length to maintain the lon'ger parts of the wall in said trough sealed by the liquid therein when the hood is raised into maximum valve opened position with the lower edge of the shorter wall part raised above the liquid in the trough into position to form a valve outlet between the shorter wall part and the trough, whereby the gas is permitted to flow through the hood and out through said outlet in valve opened position.

References Cited in the le of this patent UNITED STATES PATENTS 913,899 Joseph Mar. 2, 1909 1,494,224 Dyrssen May 13, 1924 1,499,017 Hellan June 24, 1924 2,016,484 Christensen Oct. 8, 1935 2,253,594 Wilson Aug. 26, 1941 2,633,868 Berhoudar Apr. 7, 1953 FOREIGN PATENTS 547 Great Britain Feb. 27, 1865