CA1036571A - Sealing means for sliding gate valve - Google Patents

Abstract

SEALING MEANS FOR SLIDING GATE VALVE

Abstract of the Disclosure A gate valve apparatus suitable for controlling the flow of fluids in a conduit, especially gases in high temperature applications, is disclosed. The apparatus includes a gate member adapted for sliding movement through an aperture in the gate valve assembly. Each opposing side of the aperture has fixedly mounted cooperating flat sealing strips to seal the aperture in both the conduit-open and conduit-closed positions. In certain embodiments a plurality of substan-tially parallel gate members, each having aperture sealing means, may be used to provide increased sealing effectiveness for highly toxic gaseous mediums.

Description

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1 I This invention rela~es to a gate valve apparatus for

2 ~¦ controlling the flow of fluids, especially gases, in a

3 ! conduit. The apparatus utilizes resilient, fluid-impermeable , ¦ cooperating flat sealing strips mounted on opposing sides 5 ¦ of the gate valve assembly aperture to e~'fect sealingr Or ~ I the aperture. 'L'he aperture allo~rs movement o~ a slidable 7 ¦ gate member to control the f'low of' a fluid in the conduit.
8 ¦ The flat sealing strips cooperate with the slidable gate 9 I mernber in the conduit-closed position, and overlap with 10 ¦ one another in the conduit-open posltion, to prevent 11 ¦ escape of the fluid medium through the gate valve assembly 12 ¦ aperture. ' ~' ' 13 In a gate valve of the t~pe perm:l.tting cornpl~te 1~ withdrawal of the gate mernber from the conduit, it is desirable that there be automatic means ~or sealing the 16 gate valve assembly'aperture through which the slidable-lr flow control gate member is inserted and withdrawn, so as 18 to prevent escape of the fluid through the aperture. The ~
19 j present invention provides such an automatic sealing ' 20 ¦ means which depends upon the resilient characteristics Or 21 I cooperating fluid-impermeable flat strips to e~fect 22 sealing of the aperture in both the conduit-open and 23 c'onduit-closed positions and eliminates the necessity for 24 the complex spring and cooperating sliding me~ber arrange-ments disclosed in the prior art to seal the aper~ure~
2~ These and other aspects and advantages o~ the present 27 invention are more apparent in the following detailed 28 description and claim3, partlcularly when considered in 29 conJunction with the accornpanying dra~llng, in which llke parts bear ]ike reference nurnerals.

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~TATEMENT OF INVENTION 1~3~5~
The invention as claimed herein is an apparatus for controlling the flow of a liquid comprising-(a) a conduit for the ~ransport and containment of thesaid fluid, said conduit having an aperture in its wall, generally transverse to the direction of fluid flow through the conduit and extending approximately the entire width of the conduit;
(b) a gate member adapted for sliding movement through the aperture between conduit-open position, wherein the gate member is withdrawn completely from the conduit, and conduit-closed position, ...
wherein the gate member extends through the aperture and into the conduit to restrict the flow of the said fluid through the conduit;
and ~:
(c) each conduit-traversing side of the aperture having one or more cooperating, flate sealing strips made o:E ~luid-impermeable, resilient material, the strips being Eixedly mounted in the apparatus, the combined width of one or more of the said .
fixedly mounted opposing sealing strips in a plane perpendicular :.
to the plane of the gate member being greater than the width of the aperture, such that when the gate member is withdrawn completely : .
from the conduit one or more of the opposed sealing strips overlap in flat, sealing engagement, effectively closing the aperture and .
preventing the escape of fluid therethrough, and when the gate ~ :~
member is inserted through the aperture into the conduit the flat : -sealing strips are bent aside by the gate member and biased ~ .
against the opposite faces of the gate member in sealing engagement therewith. .~
The flat sealing strips may be made of spring-tempered sheet .
metal. ;.
Preferably, each conduit-traversing side of the aperture has a plurality of the flat sealing strips, at least two of which :~ .
(on each side) are hiased against the faces of the gate member in sealing engagement therewith when the gate member is in the conduit-closed position. In a preferred embodiment each conduit- .

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traversing side of the aperture has a stack of four flat sealing strips, the two of which that are closest to the conduit being --wide enough to reinforce the other two strips but not wide enough to overlap in the conduit-open position or to engage the faces of the gate member in the conduit-closed position. ;
To prevent buckling of the flat sealing strips during withdrawl of the gate member from the conduit, it is advantageous to mount a flat retainer plate member adjacent each of the stacks of flat sealing strips. Usually the aperture is elongated, with L0 the long edges thereof extending generally transverse to the -.
direction of the fluid flow through the conduit.
Other preerred features for the apparatus of the present invention are at least one scraper blade positioned between the conduit and the flat sealing strips Eo~ dislodg:Lng fore:iqn matter from the surace o~ the gate member as it is slided into its conduit-open position, means to hold a cover plate in sealing engagement with the aperture during replacement o:E the flat sealing strips, and sealing leaf springs fixedly mounted on the side and bottom edges of the gate member to effect sealing .
engagement with the inner wall of the conduit in the conduit- :
closed position. To facilitate assembly and disassembly of the apparatus of the present invention, the stacks of flat sealing ~ ~
strips can be mounted in the apparatus by means of bayonet locking ~.
studs affixed to the apparatus and protruding through holes in the strips, with the strips being held in place on the studs by slotted locking plates.
To enhance the sealing eectiveness o:E the gate valve apparatus of the present invention, two or more of the gate members can be provided, parallel to each other. Also, two or more parallel sets o:E the cooperating flat sealing strips can be used with each blade.

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¦ IN THE DRAWINGS

1 ¦ Figure 1 is a perspective view o~ the gate valve 2 I assembly anà conduit in lcs scru~ur~l ~nvironment;
3 ¦ Figure 2 is an enlarged, detailed, fragmentary,

4 ¦ sectional view o~ the gate valve assembly aperture sealing 51 means taken along the line 2-2 of F'igure l;
~¦ ~:lgure 3 is an enlarged, detailed, fragmentary, 7 perspectlve view of the seal:lng means for the slidable 8 gate member;
9 Figure ll is a vertical, cross-sectional view of a modification of the s:Lngle slidable gate mernber sealing 11 structure of Figure 2;
12 Figure 5 ~s an enlarged, detalled, sect:l.onal v:lew o~
13 the encircled area 5 of Flgure ll;
1~ Figure 6 is a fragmentary, horizc)rltal~ sectional view taken along line 6-6 of Figure ll;
16 Figure 7 is a vertical cross-sectlonal vlew of a 17 modif`ication of the single slidable gate member sealing 18 structure of Figure 2;
19 Figure 8 is a cross-sectional view of the opposing sealing strlp stacks in the conduit-open position; and 21 Figure 9 is a cross-sectional view of the opposing 22 sealing strip stacks in the conduit-closed position.
23 In Figure 1 the gate valve assembly frarne 12 is 2~ shown in the structural environment of a conduit 10 for the transport and containment of a gaseous medium. The 2~ upper portion of the gate valve a~sembly has a gate 27 member housing 14 for containment and storage of the 28 slidable gate member 18 irl Figure 2 when the slidable 29 gate member is in the condu:lt-open posit:Lon. A rnotor 16 cooperates with rneans well known in the art (not sho~m) ~A~ -3-,, ~ 1~3657~

1 to move slidable gate memb~r 18 between the conduit-open 2 and conduit-closed positions.
3 Figure 2 presents a preferred embodiment of the means to seal the aperture 20 in the gate valve assembly frame 12 which permits insertion of the slidable gate 6 rnember 18 into the con~ult 10 to efrect flow control of 7 the gaseous mediurn. The slidable gate member 18 in 8 Figure 2 is shown in the conduit-open position. The gas 9 flow in the conduit 10, shown by the arrow, is unimpeded and the gaseous medium is prevented from escaping into 11 the slidable gate member housing lLI by the cooperating 12 flat seallng strlps :Ln staclcs 22A and 22B. The sea:L:lng 13 strips are made o~ f'luid-irnpermeab.le, resillent material.
1~ In high temperature applications it has been found that spring-tempered sheet metal sealing strips of 0.007 inches 16 are preferred, a sealing strip thickness range of about 17 0.005 to 0.01 inches being preferred. The drawings depict 18 the flat sealing strips with exaggerated thicknesses 19 relative to the dimensions of the other components of the apparatus for the purpose of facilitating pictorial 21 representation.
22 Each of the opposing sealing strip stacks 22A and 22B
23 is composed of four flat strips Or metal 22A-1 through 4 and 24 22B 1 through 4~ respectively. As depicked in Figure 8, the sea~ing of aperkure;20 when gate member 18 is in the condult-26 open position is effected by the overlapping of two or more of the sealing str~ps, i.e., by strip 22A-2 be:lng sandwiched 28 between OppOSillg strips 22B-1 and 22B-2~ This :LS the posi-29 tion of those strips at rest. As depicted in Figure 8 flexure deformed strips 22B-3 and 22B-4 exert a compressive . .

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1 ¦ force to seal cooperating overlapped strips 22B-1 and 22A-2.
¦ However, when ~ate member 18 is inserted into conduit 10, 3 ¦ as depicted in Figure 3, the sealing strips are bent aside 4 ¦ by the gate member. This creates tension in the strips, 51 resulting in their being biased against the opposite faces .
6 ¦ of gate member 18 in sealing engagement therewith. As r ¦ depicted in Figure 9, the strips being nurnerically identical . .
~¦ to the strips designated in Figure 8, only the top two seal-91 ing strips on each side (22A-1 and 2 and 22B-1 and 2) ~ .
10¦ engage gate member 18. As is apparent from the drawings, 11¦ wide varlatlon ls possible as regards the total number of 121 sealing strips employed, as we:ll as how many opposing 13¦ sealing st.rlps overlap to effect a sea:l :Ln the condult-1~¦ open position, how many opposing str-.Lps actually engage the 15 ¦ faces of the gate member to effeck a seal in the conduit-16¦ closed position, and how many, lf~any, serve only to rein- .
lr ¦ force the gate-engaging strips. I'he mlnimum requirement, of .: :
18¦ course, is one strip for each side of the aperture, so mount~ d 19¦ that they will overlap at rest, when the gate member is in 211 the conduit-open position~ and will be biased against the l opposing faces of the gate member when the latter is in 221 the conduit-closed position. It is preferred, however, that 241 there be a plurality of gate~engaging strips on each side of 25 1 the aperture, for example, two or three, and that at least l one of those gate-engaging strips be so positioned that :Lt 2GI will be guided into a sandwi.ched posit:ion between two of the . .

281 gate-engaging strips on the opposite side of the aperture :
291 when the gate is withdrawn from the aperture. It :Ls also 301 preferred that there be at least one reinforcing str:ip on ~ .
l each side of the aperture. . : ~ .

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365ql 1 ¦ Retainer plates 24A and 24B are fixedly mounted on .
2 ¦ the gate valve assembly frame 12 and contact and fixedly .
3 ¦ position the respective sealing strip stacks 22A and 22B .
4 ¦ on opposing sides of aperture 20. The retainer plates 5 ¦ 2LIA and 2llB reinforce and prevent buckling of the sealing ¦ strips when the slidable gate member 18 is withdrawn from ¦ the conduit 10. Spacer plates 26A and 26B are respectively 8 ¦ fixedly rnounted on retainer plates 24A and 24B and cooperate 9 ¦ with aperture block mounting plates 28A and 28B to form a station.for aperture blocks 32~ and 32B. The aperture 11 ¦ blocks 32A and 32B are f:ixedly mounted on the apertur~
12 ¦ block mountlng plat~s 28A and 28B b~y aperl;llre block 13 retainer plates 30A and 30B. In the prererred embodiment I 1~ for high temperature applications the aperture blocks 32A.
I 15 and 32B are Inconel cy].inders with a ceramic cloth outer .~ 16 layer. The aperture blocks 32A and 32B contact the `~
17 slidable gate member 18 in the conduit-closed position 18 (Figure 3) to operate as a secondary seal to prevent - 19 escape of the gaseous or fluid medium into gate member housing 14.
, Zl In Figure 3, a fragmentary perspective view.of the ; 22 slidable gate member 18 in the conduit-closed positlon is . , 23 ¦ presented. As described in detailed Figure 9 the coopera-24 ting flat sealin~ strlps 22A 1 and 2 and 22B-1 and 2 contact the slidab~e gate member 18 to ef~ect sealing and 26 prevent escape of the fluid medium through the aperture 27 20 into the gate member houslng 14. Flat seallng str:lps 28 22A-3 and ll and 22B-3 and 4, protruding a shorter distance 29 into the aperture than f.lat sealing strips 22~-1 and 2 and 22B-1 and 2 do not:contact the slidable gate member _ ~; _ l (~ ( ~3S57~
1 18 but serve to bias flat sealin~ strips 22A-1 and 2 and 2 22B-1 and 2 a~ainst the opposite faces of slidable gate 3 member 18 by applying axial contacting pressure in the ; ' 4 conduit-closed position to seal aperture 20.
The lower port-Lon of the ~ragmented view presented

6 in Pigure 3 demonstrates one means for erfecting a seal ,,~

7 between the slidable gate member 18 and the side and

8 bottom walls of the gate valve assembly frame 12 when the , ''

9 valve is in the conduit-closed position. Upstream inner side w~ll guide flange member 34 is attached to side'wall 11 guide flange plates 35 whlch are f'lxedly rnounted on the 12 side wall of' gate valve assembly rrame 12 at spaced 13 intervals of pref`erably 10 to 14 :Lnche~ arld cooperate wlth 14 downstream inner flange 36 to form a guide channel for the slidable gate rnember 18. The use of spaced upstream inner 16 side wall guide flange plates 35 ls preferred over a r 17 continuous upstream flange member directly affixed ~o the 18 side wall of the gate valve assembly frame 12, which would :
form a pocket for the accumulation of foreign matter in 20 the guide channel. The arrow in Figure 3 defines the ~
21 direction of fluid flow in the conduit. It will be noted ~i 22 that the fluid flow exerts a positive pressure to promote 223 contacting of the downstream surface of the slidable gate member 18 with the respective cooperating flat surface of the downstream inner flange 36, thereby preventing leakage 27 of the gas or fluid around the slidable gate member 18 28 when it is in the conduit-closed position. The upstream 29 bottom wall has an upstream continuous seating flange 38 ~ ~.
which cooperates with the downstream inner flange 36 to 30 form a seating channel for the bottom edge of the slidable . ~'',':'' -7- ;

1 gate member 18. ~:
2 Figure 4 is a verti.cal cross-sectional view of a 3 modification of the sliding gate valve assembly~ showing ; :.
the arrangement of two, parallel sl:idable gate members of .
5 the type depicted -in Figure 2. The upper frag~ented :
6 portion of' F'lgure 4 clemonstrates that the gate member :
housing 14 has cooperating gate housing guide channel ~:
8 members 40A and 40B, which are fixedly mounted on the .
9 sides of the gate member housing 14 and de.fine a trough 11 to guide the sl.ldable gate member 18 during insertlon and .withdrawal.
12 S:Lnce th~ aperture ~eallng means o.E' the two slidable 13 gate member arrangements p:resented ln t;he upper fragmentary 14 portion of' Figure 4 are identical, only.the right side aperture sealing means has been supplemented with identifying 16 numerals. The arrow shows the fluid flo~ direction in lr , ., conduit 10. ~

19 A modification of the gate valve assembly is shown in Figure 4 with the inclusion of cooperating guide channel.

21 members 44A and 44B which are fixedly mounted to the gate valve assembly frame 12 below the flat sealing strips 22A

23 and 22B. The cooperating guide channel members 44A and 4LIB form a channel for the placement and retention of a 2~
slidable sealing cover plate 60 (Figure 7) which may be inserted through the channel in the concluit-open posit:ion to seal aperture 20 during the replacement or repair of the flat sealing strip stacks 22~ and 22R.

In the conduit-closed posltion the paralle:l slidable gate member arrangement of Figure~LI provides positive pressure sea-ting of the slidable gate members 18 against `:

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1 the inner side wall guide and sealing flanges 50 and the '~
2 inner bottom wall sealing ~langes 51. The bottom wall ' .
3 sealing flanges 51 cooperate with inner bottom wall guide 4 flanges 53 to form a seating channel for the slidable gate mernber 18. Convent:ional blower means (not shown) '' "
6 cooperating with a conduit aperture 63 are pro~rided to 7 introduce a positive air pressure in the space 57 between ;, ;, .
8 the parallel slidable gate members 18 relative to the . ' .
9 pressure exerted by the gaseous medium in conduit 10. The , '.

10 blower is provided with conventional sea-Llng means (a'lso

11 not shown) such as an angle waf'er valve at the b:lower

12 output hea(:l to prevent backf`low of the y,aseou~ med:lum inl;o

13 the blower assernbly in the condu:lt-open valve position. .

14 The positive pressure exerts an outward force to bias the slidable gate member,s 18 against. the inner side wall gulde . .
16 and seali.ng flanges 50 and the inner bottom wall sealing '' ' 17 flanges 51. The only sealing surface leakage which can .
18 occur in this paral'lel slidable gate member arrangement ,.
19 under the positive pressure c,onditions in space 57 is ,....... ~ .
outward from space 57 into the conduit 10. This arrangement ., 21 is desirable in instances where a temporary interruption ,:
22 of the transport of a highl.y toxic fluid in conduit 10 is . ' `~.. ', 23 necessary . ' ; ' 24 In Figure 5, ln enlarged view, i3 shown a preferred : :.

26 seating means f'or the bottorn edge of gate mernber lf3 .
2 Again, the arrow indicates the direction of fluid flow. ,:
7 Spring seal member 46 is flxedly mounted on the bottom ,.
28 edge of slidable gate member 18 and cooperates in sealing compression with the bottom surfa.ce of the gate valve .
~0 assernbly frame 12. Additionally, the upstream surface of , . ., . ' . ,~
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1 slidable gate member 18 contacts the surface of inner 2 bottom wall sealing flange 51 to effect a further seal to 3 prevent fluid ~low around the slidable gate member 18. . .' In Figure 6 the horizontal view of the side wall of the two parallel slidable gate rnember arrangements of' Figure 4 is ~ presented. lntermittent spacer channel plates 48 are r fixedly mounted on the side wa].l of the gate valve assembly 8 frame 12 to fixedly position continuous guide flange members 9 49 which cooperate with the continuous inner side wall guide ,.
10 and seallng :flanges 50 to deflne a gulde channel for the . ~ '.
11 slidable gate member 18. Under the pos:ltive b:l.as pressure 12 introduced lnto space 57 the upst:ream su:rf'ace of sl:ldable 13 gate member :l8 contact~; the ~u:rfacc~ of' the :Inner s~de wall .14 gulde and sealing flange 50 to ef'fect a seal to prevent fluid flow around the slidable gate member 18.
16 Fl~ure 7 depicts a modiflcation o~ the aperture sealing 17 means of Figure 2 wherein an upper second spring seal.
18 assembly, identical,in all respects to the lower spring 19 seal assembly, is used in place of the aperture blocks. .,.. ' 32A and 32B of Figure 2. In this type of tandem spring 21 seal arrangement, the upper spring seal assembly operates ., 22 as a secondary seal to better prevent leakage through 23 aperture 20 ln both the conduit-open and conduit-closed 2~ positions.
25 ~igure 7 depicts.:a ~urther modification of the apertu:re ..
26 sealing means by the addition of scraper plates 56A and 27 56B mounted on scraper mounting plates 58A and 58B. In 28 the preferred embodlment the scraper plates 56A and 56B .~
29 are flat metal plates of approximately 0.1 to 0.2 inch ..
thickness which scrape foreign matter off the slldable :

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1 gate member 18 on insertion and withdrawal from the 2 conduit 10.
3 A further modification depicted in Figure 7 is a 4 means to attach the tandem sealing cartrldge 62 to the gate valve assembly frarne 12. A serles of bayonet locking 6 studs, of whlch one is shown 63, ls fixedly mounted on the 7 gate valve assembly frame 12 and cooperates with a slotted 8 locking plate 64 to fixedly mount the tandem sealing 9 cartridge 62. In this embodiment, as opposed to the use of threaded rasteners, e.g., nuts and boLts, the tlme and 11 erfort required to rernove and replace sealln~ cartridge 62 12 are greatly f'ac:llLtated. [t w:Lll be app:rec:Lated t,hat thls 13 means of mounting the aperture sea:Ling means may be used 1~ in all the embodiments presented herein, and is not restrlcted ln lts usefulness to the tandern sealing cartridge 16 depicted in Flgure 7.
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Claims (13)

WE CLAIM:

1. An apparatus for controlling the flow of a fluid comprising:
(a) a conduit for the transport and containment of the said fluid, said conduit having an aperture in its wall, generally transverse to the direction of fluid flow through the conduit and extending approximately the entire width of the conduit;
(b) a gate member adapted for sliding movement through the aperture between conduit-open position, wherein the gate member is withdrawn completely from the conduit, and conduit-closed position, wherein the gate member extends through the aperture and into the conduit to restrict the flow of the said fluid through the conduit;
(c) each conduit-transversing side of the aperture having one or more cooperating, flat sealing strips made of fluid-impermeable, resilient material, the strips being fixedly mounted in the apparatus, the combined width of one or more of the said fixedly mounted opposing sealing strips in a plane perpendicular to the plane of the said gate member being greater than the width of the said aperture, such that when the gate member is withdrawn completely from the conduit one or more of the opposed sealing strips overlap in flat, sealing engagement, effectively closing the aperture and preventing the escape of fluid therethrough, and when the gate member is inserted through the aperture into the conduit the said flat sealing strips are bent aside by the gate member and biased against the opposite faces of the gate member in sealing engagement therewith.

2. The apparatus of claim 1 wherein the said flat sealing strips are made of spring-tempered sheet metal.

3. The apparatus of claim 1 wherein each conduit-traversing side of the aperture has a plurality of said flat sealing strips.

4. The apparatus of claim 3 wherein at least two of the sealing strips on each conduit-traversing side of the aperture are biased against the faces of the gate member in sealing engagement therewith when the gate member is in the conduit-closed position.

5. The apparatus of claim 4 wherein each conduit-traversing side of the aperture has a stack of four flat sealing strips, the two of which that are closest to the conduit being wide enough to reinforce the other two strips but not wide enough to overlap in the conduit-open position or to engage the faces of the gate member in the conduit-closed position.

6. The apparatus of claim 1 wherein there is mounted adjacent each of the said flat sealing strips a flat retainer plate member to prevent buckling of the said flat sealing strips during withdrawal of the said gate member from the said conduit.

7. The apparatus of claim 1 wherein the aperture is elongated and the long edges thereof extend generally transverse to the direction of fluid flow through the conduit.

8. The apparatus of claim 1 with at least one scraper blade positioned between the conduit and the said flat sealing strips for dislodging foreign matter from the surface of the gate member as it is slided into its conduit-open position.

9. The apparatus of claim 1 with means to hold a cover plate in sealing engagement with the said aperture during replacement of the said flat sealing strips.

10. The apparatus of claim 1 with two or more gate members in parallel arrangement.

11. The apparatus of claim 1 with two or more sets of cooperating flat sealing strips in parallel arrangement to seal the said aperture.

12. The apparatus of claim 1 with sealing least springs fixedly mounted on the side and bottom edges of the gate member to effect sealing engagement with the inner wall of the conduit in the conduit-closed position.

13. The apparatus of claim 1 wherein the said flat sealing strips are mounted in the apparatus by means of bayonet locking studs affixed to the apparatus and protruding through holes in the strips, said strips being held in place on said studs by a slotted locking plate.