CA1085807A - Resilient seated gate valve with improved seat arrangement - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A gate valve structure for use in mains carrying fluids, the gate valve structure being provided with an improved valve seat arrangement. The gate valve includes a casing having an unobstructed through-bore and a substantially rectangular shape or elongated chamber communicating with the through-bore in which a gate or disc member reciprocates between closed and opened positions of the valve. The valve casing is provided with a valve seat surrounding one of the ports in the casing defined at the inter-section of the through-bore by the elongated chamber, the valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore and the seat has an upper planar portion facing the other of the ports except at the bottom portion where it merges smoothly into and forms a portion of the unobstructed through-bore. The gate member is provided with a resilient seal member for seating on the valve seat, the seal member having a configuration to conform to the seat so that the seal member is not damaged during opening or closing of the valve by edges in the interior of the valve resulting from the machining of the valve seat. Further, because of the irregular shape of the resilient seal member, means are provided so that the seal member may be properly oriented onto the gate member during assembly and the gate member is provided with ears which cooperate with guideways in the valve casing in such a manner as to minimize rock of the gate member during opening and closing of the valve regardless of the direction of flow of fluid through the valve and, thus, eliminating problems resulting in damaging of the resilient seal member from the wedging action in closing.

Description

3 Th~ present invention relates to an improved gate valve 4 ~ st.ructure and, more particularly, to a gate valve structure 5 having an imprGved seat arrangement i~cluding a machined valve 6 seat in ~he valve casing surrounding one of the ports in the 7 throuyh-bore ~nd lying generally in a plane which converge~ at 8 an acute angle to a plane normal to ~he axis of the through-bore 9 and to an improved annular resilient seal member ~arried by the bQdy member of ~he gate member for engaging a~d sealing with the 11 valve seat. The particular configuration of the valve seat and ~2 ~he annular resilient seal member and its ~ounting on the body ~3 member of the gate member obviates damage to the annular seal 14 ~ember caused by the wedging act:ion of the.same when making a ~5 ~eal to close the gate valve.

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~ ii8~7 BACKGROUND OF THE INVENTION

3 Heretofore, gate valves utilizing a reciprocating gate 4 ~ember have included a cast body member having a through-bore and a valve seat machined therein surrounding one of the ports 6 in the through-bore and a bonnet attached to the body member 7 which provides a chamber open to the through-bore and which 8 conltains ~he rising or non-rising valve stem for the gate member 9 and space for the gate member when the valve is open. Such prior 1~ type of gate valve structure is shown in Applicant's Canadian .. _ .. . . . .
11 Patent 951 304 granted July 16, 1974 and Patent 961 470 granted 12 January 21, 1975. This type of gate valve included 13 a gate member whlGh was reciprocated from an open position where 14 the gate member was out of the through-bore and the through-bore was completely unobstructèd to thereby reduce turbulence and currents 16 within the valve structure and provide for smoother flow with .;, .
~ ~7 less pressure drop, to a position across the through-bore so as `,',i 18 to close- the valve. While the gate valve was of the resilient 19 seated type in that the gate member was provided with a resilient ..
covering, the valve seat was of a rather complicated shape and 21 required an expensive operation to machi~e the same and, in fact, 22 involved certain manufacturing difficulties since machining was 23 accomplished either through the opening in the upper part of the 24 casing or through the ports of the through-bore.

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More recently, gate valve struc-tures have been developed 2 uch as those disclosed in Applicant ' s prior United

3 States Patent 3, 963, 214, issue~ June 15, 1976 to ~Iackman et al .

4 ~his type o gate valve i~cluded a valve seat surrounding one o the ports i~ the through-bore and lying generally in a plane 6 converging a~ an acu~e angle to a plane normal to the axis of .;
7 the through-b~re. The patent inoluded a gate member having ~n 8 a~ular seal ~ember ~hereon, he seal member having a bulbvus ~ 9 portion surrounding its entire periphery for engaging the valve - lO sea~, the valve sea~ having a planar surface facing the o~her ll por~ and a bottom ~urface merging into and forming part of the 12 ~hrough-bore. How~ver, it has been found ~hat difficulties are 13 encou~tered with ~his type of sea~ arrangement as an edge is 14 creat~d a~ ~he intersec~ of the seat with ~he area of ~he casing lS surxounaing ~h~ through-bore and as a result o the uniformed 1~ shaped annular seal member, the same dragged ~cross this edge 17 resulti~g in tearing or cutting of the same duri~g closing and ~8 op~ning o the val~e a~d particularly i~ c~osing when a wedging 19 action is created on the upper portion of the annular seal member as ~he lower portion is placed u~der compression with ~he bo~om . 21 of th~ through bore. The valv~ casing in this prior art ~ype 2~ of gate valve was forTned of two bc7dy.members which were split 23 a plane n~rmal to the axis of ::he through-bore, the two boay 24 m~mbers being se~ured to ~ach other to define the cham~er and l~- 25 the thr ugh bore and one body membex contained the valve seat.

8~7 1 It was thought that by providing the valve casing split in this 2 manner it would be easier to machine the valve seat in one of 3 the bo~y members. ~owever, such machining of this type of seat 4 can be accomplished in khe conventional type of gate valve wherein the valve casing includes a body member defining the seat and the 6 through-bore and a bonnet for defining the chamber for the valve 7 operating mechanism and for the gate member when the ~alve is in 8 the open posikion.
' ..1 9 The gate member of the gate valve struc~ure disclosed in the aforementioned Canadian patents provided an arcuate shoulder which 11 axially exkended from the planar seating surface for the annular 12 seal member, the arcuate shoulder being arranged to enclose the 13 outer periphery Qf th~ annular seal member on its upper portion.

14 With such an arrangement and since there was wedging actlon created during closing on the upper portion of the seal member, this 16 wedging action was somewhat like a shearing action and conse~uently, 17 there was a flow o~ the resilient seal member. However, this 18 flow was such that ik could not take place within the shoulder lg area and since there was no place for the material o the seal member to go, it was cut on the sharp circumfere~tial ends of 21 the arcuate shoulder. This resulks in the valve having a damaged 22 sealing sur~ace on the seal member ater a number of openings and 23 closings, thus, requiring the seal member to be changed. ~his damage to the seal member was in addition to the damage caused by the seal member dragging across the edge creaked during the machining of the valve seatO

3 The following patents represent prior ar~ disclosing gate 4 valve structures wherein the valve seat is arranged to lie generally in a piane which converges at an angle ~o a plane 6 normal to the axis of the through-bore and wherein the gate 7 member is provided with a resillent annular seal member.
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1~ 1,557,926 Dopp October 20, 1925 12 2,194g261 Allen March 19, 1940 13 2,870,987 Greenwood January 27, l9S9 14 - 3~316r929 Milette May 2, 1967 3 j434,693 Britto~ -- March 25, 1969 19 1,600,753 Gexman January 8, 1970 . ~ .

~S8~7 BRIEF SUMMARY OF THE INVENTION

3 Th~ gate valve stxucture of the present invention is 4 primarily utilized for mains carrying fluid under pressure S such as mains in a water distribution system. While the gate 6 valve structure may be utilized for small diameter water mains, 7 it may also be utilized in large diamPter mains and it is 8 designed so that it can be inserted into the main with the valve 9 seat, eithex positioned upstream or downstream of the gate member without effecting the valves operation in closing off the water 11 distribution system. While the gate valve structure is primarily 12 intended for use in water distribution systems, it may also be . 13 used in fluid distribution systems such as chemical, steam, gas, 14 oil or the like, i~ being undersl:ood that the various parts of the gate valve structure must be made from or coated with materials 16 to inhibit possible corrosive action within the valve structure 17 dependi~g upon the type of ~luid used in the system.
1~ The gate valve structure of the present invention includes a 19 valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting the through-bore intermediate its 21 ends and defining in the through-bore inlet and outlet ports to 22 the cham~er, one of the inlet or outlet ports being surrounded 23 ~y a valve seat which lies generally in a plane converging at an 24 acute angle to a plane normal to the axis of the through-bore.
~J 25 The valve seat has an upper planar portion facing toward the -8~

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1 other of the ports and it merges at its lower portion into and forms a portion of the through-bore so that the through-bore is unobstructedO A generally flat gate member reciprocates in the elongated chamber from a closed position across the through-bore and seating against the valve seat to an open position out 6 of the through-bore. The gate member includes a body member ? having an.annular resilient seal member generally rectangular in 8 radial section mounted thereon, the annular seal member having : a bulbous portion extending axially therefrom for engaging the planar portion of the ~alve seat, the bulbous portion of the 11 seal member having a maximum axial thickness adjacent its upper 12 portion in a plane extending through an axis of movement of the . 13 gate member. The bulbous portion.o~ the annular resilient seal 14 member merges into the rectangular lower portion of the seal member and khe min~mum axial thickness of the seal member is at the lower 16 portion in the same plane as the maximum thickness. Means are 17 provided for retaining the seal member on the body member and ~ 18 valve stem means are operatively connected to the gate member and : extend through the valve casing, the valve stem means being operative to move the gate member between closed and opened positions.
21 By providing an annular resilient seal member with a bulbous 22 portion extending axially of the same-in the upper portion thereof 23 and the bulbous portion then merging into the rectangular cross-24 sectional configuration thereof, the annular seal member does not j 25 have its sealing surface marred by the shearing action of contact with the valve seat in the. area of where an edge is formed during 2 the machining operation of thé valve seat. Such arrangement still 3 provides''for sufficient pressure between the annular seal member 4 and the valve seat regardless of wh~ther it is ~n the portion of the seal member which is provided with an axial wedging action, 6 ~amely, the upper portion of the annular seal member or the lower 7 portion of the annular seal mem~er where the sealing action is 8 compression- `
9 . Another aspect of the present invention is to ~rovide 'a recess about the outer periphery of the valve'seat in ~he'area 11 of the top of the same so that the larye amount of squeeze or 12 wedging.action encountered by the seal mem~er in thi:s area does 13 not result in damage to the same by the sharp edge'located at this 14 '.point of the valve seat.
Still another aspect of the present invention is to provide 16 an annular seal member for a gate valve which.has a non-uniform 17 shape and consequently, must be accurately positioned on the gate 18 membery thus, means are.provided to ensure proper orientation 19 of the seal member during assembly of the'gate member~
A further aspect of the present invention ls to pro~ide means 21 on the ~ody membex of said gate member to accommodate for ~low 22 of the annular resilient seal member in an area adjacent to the 23 circumferential ends of the arcuate shaped shoulder which'extends 24 about the outer periphery of the upper portion of t~e annular seal member. The means includes providing recesses adjacent to the circumferential ends of the arcuate shouldsr.

1 Another aspect o~ the present invention i~ providing the 2 resilient annular seal member'of the gate memb.er w~th'an em~edded 3 reinfor~ing member. I.n this respect, an annular steeI reinforc~ng 4 ring is embedd~d into the. resilient seal member when the member is

- 5 molded and the ring provides a means for disc~iminately applying

6 pressure to seal member when i~ is attached ~o the ~ody member of

7 the gate member and for subsequent adjustment thereof~ A plurality

8 of scr ws extending through holes provided in t~e's.tee'l re~nforcing

9 member and recelved in tapped holes on the''body member can he individually adjusted to apply pressure at discre~e'points around .,' - 11 the flat steel reinforcing member and, thus, the sealing contact 12 o the seal member with the'~alve seat may be adjustea at a.ssembly 13 of the gate valve and after use of the gate valve.
14 ~ncillary to the above, the annular seal member seats on a planar surace on the gate member and in order t~ provide a good 1~ seat, the back face of the annular seal member is provided with an 17 annular bead so as to initially provide line contact when the screws 1~ attach the seal member to the body member of the gate memb~r~
19 Another aspect of the present invention which further ensures excellent sealing of the gate valve when in the closed position 21 and also ensures less damage to the seating surface of the annular 22 seal member is the provision o ears operating in guideways in 23 th~ valve casing, the ears on the gate member having a length 24 which extends almost to the bottom of the gate member so that the ~J ~5 rocking of the gate member upon closing or opening is reduced to .

~5~7 a minimum. Additionally, the width of the guideways and the width of the ears is carefully controlled to eliminate disc rattle when the gate member is in the open position.
In accordance with one broad aspect, the invention relates to a gate valve structure for use in mains carrying a fluid, said gate valve structure comprising: a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through-bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which con~erges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar : portion facing toward the other of said ports except at a : bottom portion thereof where it merges into and forms a smooth and uninterrupted portion of said through-bore, said planar portion of said valve seat having an outer arcuate edge; a ~: generally flat gate member reciprocable in said elongated : chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member having an annular planar surface lying generally in a plane converging at an acute angle to a plane normal to the axis of the through-bore and generally complementary to the plane of said valve seat, said planar surface of said body member being surrounded on its radially outer periphery adjacent its upper portion by an arcuate shoulder terminating in circumferentially spaced ends and extending axially from the body member, said planar surface being further provided on its radially inner periphery by an annular shoulder extending axially from the body mernber, an annular resilient seal member received on said ~6J38~ 7 planar surface and bounded by the annular shoulder and the arcuate shoulder, said annular seal membex being generally rectangular in radial section and having an upper bulbous portion extending a~ially therefrom for engaging the upper portion of said valve seat facing the other of said ports, said bulbous portion of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness of said seal member at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position, and said bulbous portion of said seal member preventing the lower portion of said seal member ~rom dragging across said edge of said seat when said gate member is opened and closed; means for retaining said seal member on the body member of said gate member; and valve stem means operatively connected to said gate member and extending through said valve casing, said valve stem means being operative to move said gate member between the closed and opened positions.
These and other features and advantages of the present invention will appear more fully in the following Detailed Description of the Invention when taken with reference to the drawings.

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BRIEF DESCRIPTION OF THE DRAWINGS

3 Figure 1 is a vertical sectional view through the gate 4 valve structure of the present invention taken on a plane parallel to the through-bore of the same and illustrating 6 the gate member in the opened position, the valve stem operating 7 mechanism being partially shown in elevation.
8 Figure 2 is an enlarged vertical sectional view through the 9 lower body member of the valve casing, the view being taken 1~ substantially on the line 2 2 of Figure 1.
11 Figure 3 is an enlarged fragmentary horizontal sectional 12 view of the lower body member of the valve casing taken sub-13 stantially on the line 3-3 of Figure 1 and rotated 90 degreQs 14 clockwise.
Figure 4 is an enlarged side elevational view of the gate ~6 member with a portion of the annular resilient seal member broken 17 awayO
18 Figure 5 is a vertical sectional view of the gate member 19 of Figure 4 taken substantially on the line 5-5 of Figure 4.
~ Figure 6 is a perspective view of the resilient annular 2~ seal member of the gate member.
22 Figure 7 is a sectional view taken substantially on the 23 line 7-7 of Figure ~. -24 Figure 8 is a sectional view taken substantially on the line 8-8 of Figure 6 and illustrating the transition of the bulbous portion.

1 Figure 9 is a sectional view taken substantially on the 2 line 9-9 of Figure 6.
3 Figure 10 is an enlarged vertical sectional view of the 4 resilient annular seal member of the gate member, the view illustrating the seal member just prior to closing with the 6 bulbous pox~ion in contact with the valve sea~, the valve seat 7 a~d the valve casing being shown in broken lines.

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DETAILED DESCRIPTION OF THE INVENTION
: 2 3 Re~erring now to the drawings wherein like characters or 4 reference numerals represent like or similar parts, the gate valve structure of the present invention is generally illustrated in Figure 1~ In more detail, the gate valve structure includes a 7 valve oasing generally designated at lO, the ~alve casing being 8 provided with a through-bore 12, a chamber 14 intersecting the 9 ~hrough-bore 12 and defining ports 16 and 18 in the through-bore, and flanges Z0 and 22 arranged to receive suitable means for ll attaching the ga'e valve structure to the pipes or mains P and M
12 respectively shown in broken lines. The ports 16 and 18 may be 13 inlet or outlet ports to the chamber 14 depending upon which .
14 way the gate valve structure is inserted into the fluid distribution system. In other words, the gate valve structure ls a two-way l~ structure as pressure of fluid in the fluid distribution system 17 does not effect the sealing upon closing of the valve structure.

18 The valve casing lO may be of the conventional type in that it l9 includes a lower body member 24 and a bonnet 26 attached thereto b~ means of bolts 28. Of course, the valve casing lO could be 21 of the type disclosed in the afore~entioned Patent 3,963,214 in 2~ - which the casing is formed from two shell-like body members, the ~`

body members being attached to one another on a plane normal to 24 the axis of the through-bore and to this extent the a~orementioned patent is incorporated herein by reference.

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, 1 A valve seat 30, as best shown in Figure 2 surrounds the 2 port 16 of the through-bore 12 at a position where the through-3 bore is intersected by the chamber 14, the ~alve seat merging 4 with the bottom portion of the through-bore as indicated at 32.
rhus, it will be noted that the through-bore 12 has its bottom 6 portion throughou~ its entire length completely unobstructed 7 with no bottom ca~ity for receiving the gate member. Referring 8 more to tha valve seat 30, it will be noted by reference to 9 Figures 1, 2 and 3 that the valve seat ~as an upper portion designated by the numeral 34 which is substantially planar and 11 extends downwardly and merges in a transition portion 36 into 1~ the bottom portion 32 which defines a continuation of the through-13 bore. The planar surface 34 which faces the other port 18 extends 14 general~y on an acute anglQ to a plane normal to the axis of the thxough-bore 12 and preferably the angle is approximately 10 degrees.
16 The wall surface of the cham~er :L4 which surrounds the outer 17 periphery of the valve seat 30 adjacent its upper portion 34 is 18 recessed sharply away fxom the plane of the valve seat by an 19 angle of approximately 60 degrees, this recessed area being identified by the numeral 38 in Figures 1 and 20 A more detailed 21 descriptio~ of the purpose of the recess 38 will follow later in -~2 the specification.
23 Cooperating with the valve seat 30 is a gate or disc member 24 40, the gate or disc member 40 being reciprocated in the chamber 14 from an opened position (as shown in Figure 1) to a closed :

1 position (as shown diagrammatically in Figure 10) by valve stem 2 means generally designated at 42. Be~ore yiving a detailed 3 description of the ga~e member 40, a description will be given 4 of the valve stem operating means 42.
As best shown in Figure 1, the gate member 40 is provided 6 with a chamber 42 open at its upper end for receiving a valve 7 operating stem 44 which extends through an annular brass bushing 8 46. The bushing 46 is interiorly threaded to receive the exterior 9 threads of the valve operating stem 44 and the valve operating stem extends upwardly and through a stuffing box 48 detachably 11 secured to the upper end of the bonnet 26. It will now be 1~ appreciated that th~ valve illustrated is of the non-rising stem 13 type, but of course, it could be of the rising stem i so desired.
14 In more detail, the stuffing box 48 entraps an annular flange ~5 50 on the valve stem 44 with the usual anti-friction washer 52 1~ ~eing provided between the flange and the stuffing box. O-rings 17 54 are provided between the valve stem 44 and the bonnet 28 as 18 well as between the valve stem 44 and the stufing box 48 and a 19 further ~tuffing box gasket 56 is provided between the stu~fing box and the end of the bonnet. An operating nut 58 is carried on the 21 end portion of the valve stem ~4 extending out of the stuffing 22 box 48,-the operating nut being non-circular in external configura-23 tion as well as internal configuration, with the internal 24 con~iguration being complementary to the non-circular end portion ~ , ~ 2S of the valve operating stem.
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1 The.'gate m.ember 40 i.5 ~est shown in Figures 4 and S and it 2 w~11 be noted that it Includes a ca$t ~ody member 60 which is 3 provided,with an annular planar surface 62 for receiving an 4 annular resilient seal member 64. In more,'detail, the'annular planar surface 62 ~s provided about its radlal mner periphery 6 with a shoulder 66, the'shoulder extend~ng n~rm~l to the.planar 7 surface in a generally axial direction f~om the same~ ~ further 8 arcuate s~oulder 68 is provided a~out a port~on of the radia,l 9 outer periphery of the planar sur~ace 62''adj~cent t~e.'top ~ort~on thereof, the shoulder 68 also ex.tending normal to the'planar 11 surface 62 in a generally axial direction fro~ the same~', As w~ll.
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1~ be appreciated by reference'to Figures 1 and 5~ the. planar sur~ace 13 62 lies in a plane extending at an acute'angle to ~ hor~zontal .
14 axis of the disc, the angle. of the planar surfac~ ~2 ~eing in tfia order of 10 degrees.
16 The shoulders 66 and 68 function to restrain the .se~l member 17 64, the shoulder 66 restraining the radial inner periphery or edge 18 of the seal member 64 whereas t~e'shoulder &S re.str~ins Qnly the 19 upper portion of the outer rad~al periphery or edge of the seal member 64. The planar surface'62 of the body mem~er 40 is provided 21 with oppositely disposed recesses 70 at the circumferential ends 22 of the axcuate shouldex 68. The purpose of the:recesses 7Q is 23 to provide an area on the.'planar ~ace surface 62 wherein material 24 from the resilient seàl mem~ex 6~ can flow when the valve ~s ~eing closed and the seal member 64 i5 engagin~ the upper planar portion . ' .

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, 1 34 o~ the valve seat 30 by a wedging action. Without the recesses 2 70, there is no place for the flow of material and the sealing 3 surface ~f the seal member 64 would be damaged on the circumferential 4 ends of the annular shoulder 68.
A recess is provided in the annular shoulder 66 as indicated 6 at 72. This recess 7~ is offset from a horizontal or a vertical 7 line through the planar surface 62 and is for the use in orienting 8 , the seal member 64 when it is assembled on the gate membex 40.
9 Referri~g now ~o Figures 6 through 9 inclusive, it will be noted that the annular resilient seal member 64 is provided with 11 a radially inwardly projecting tab 74 and this tab is discriminately 12 located ~or cooperating with the recess 72 so that the seal member 13 can only be placed onto the plan~r surface 62 of the body member 14 60 in one position. This ~s n~cessary due to the irregular shape of the bulbous portion of the seal member 64. As will be noted in ~6 Figure 6, the line 76 represents a vertical axis whereas the line 17 78 represents a horizontal axis of the seal member 64 when it is 18 positioned on the body member 60 of the gate member 40. The seal 19 member 64 is generally rectangular in radial section but it has . .
an annular bulbous portion extending axially thererom, the bulbous ~ 21 portion being identified by the numeral 80..... As shown in Figures :~ 2~ 7, 8 and 9, the bulbous portion extends about the upper half of 23 the seal member 64 a~d then it begins to merge into the rectangular ~4 shaped lower portion of the seal member 64 as shown in Figure 9.
The maximum axial thickness of the bulbous portion, when the seal .

1 member is mo~nted onto the planar surface 62 o~ the body member 2 60, lies in a plane through the vertical axis 76. As will be 3 notedl ~his bulbous portion merges ~s shown in Figure 8 until it 4 flattens out into the generally rectangular radial section of the seal member.
6 The seal member is made of any suitable elastomeric material 7 such as rubber, rubber~like materials, neoprene, plastics or the 8 . li~e, so long as the material has suficient resiliency to provide 9 a proper seal~ A stainless steel, brass, or the like reinforcing ring 82 is embedded into the seal member 60 during molding of the 11 same so as to give the same some rigidity and also to act as a 12 bearing plate for the heads o~ screws 84 which extend through holes 13 85 in the.same and are threaded into holes 86 tapped into the 14 planar surface 62 of the body member 60. The back race 88 of the annu~ar seal member is provided with an annular bead 90 which .; .
16 functions to smooth ou~ when pressure is applied thereto by tighten-17 ing of the screws 84~ Of course, the screws can be discriminately 18 tightened to apply different pressure at discrete points on the 19 resilient annular seal member so that the seating of the same can 2~ be accurately adjusted for the particular seat of the particular 21 valve in which it is installed. Additionally, after continlled use 22 of khe valve and if it is desired, the screws may be further 23 adjusted to re-adjust the seating capabilities of the valve.
24 The ch~mber 14 of the valve casing 10 both in the body membPr ~5 24 and bonnet 26 is provided with a pair of oppositely disposed .

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1 guideways 92 as best shown in Figures 2 and 3. The guideways 2 92 are arranged to recei~e oppositely disposed and projecting 3 ears 94 extending from the side edges of body member 60 of the 4 gate member 40. The ears 94 are elongated and as shown in Figures4 and 5, they extend almost to the bottom of the gate 6 member 40 and tha purpose of having the ears extend almost to 7 the bottom of the gate member is so that when the valve is 8 opened and closed, the flow of fluid, regardless of which direction 9 i~ is from, does not cause excessive rocking of the gate member.
In this respect, the width of the guideways 92 and the width of 11 the ears is carefully controlled to eliminate as much play as -i 12 possible of the gate member as it. s~ides up and down in the sub-13 stantially rectangular chamber 14.
14 . While the body member 24 is casb with the guideways 92 ~5 therein, the seat 30 is machined and in the upper area thereof 16 wherein there is the recessed surface 38, an edge 100 is provided.
17 By providin~ the recessed sur~ace 38 and also by shaping the .
annular resilient seal member so that the bulbous portion 80 thereof 19 varies in its axial thickness, the lower portion of the annular :.................................... r seal does not drag across this edge 100 and, thus, the seal is not ~1 damaged upon continued opening and closing of the valve. Further, ~2 the provision of the recesses 70 in the planar surface 62 of the ;

: 23 body member 60 of the gate member 40 prevent the annular resilient 24 seal 64 from being damaged upon closing of the same wherein there :~ 25 is a wedging action of the bulbous portion 80 against the seat 1 as the material o the annular seal member can flow into these 2 recesses and, thus, the circumferential ends of the arcuate 3 shoulder 68 do not dig into the surace of the seal member 64.
4 These features are further enhanced by providing the seal member with means that ma~e it impossible to incorrectly install the 6 seal member 60 onto the body member 64. The seal member 64 is 7 provided with the tab 74 which seats in the recess 72 and, thus, 8 the bulbous portion is always correctly oriented and since the 9 rscess 72 is offset from the vertical, it is impossible to

10 incorrec~ly place the seal member onto the body member.

11 It will be appreci~ted by those skilled in the art that the ~2 interior of the gate valve may be suitably coated with corrosive ~3 coatings dependent upon the fluid used in the fluid distribution 14 system. Also, the material from which the valve casing is made can be selected to be compatible to the particular fluid o~
16 intended use for the gate valve 17 The terminology used throughout this specification is for 18 the purpose of description and not limitation, the scope of the 19 invention being defined in the appended claims.

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Claims (20)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A gate valve structure for use in mains carrying a fluid, said gate valve structure comprising:
a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through-bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar portion facing toward the other of said ports except at a bottom portion thereof where it merges into and forms a smooth and uninterrupted portion of said through-bore, said planar portion of said valve seat having an outer arcuate edge;
a generally flat gate member reciprocable in said elongated chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member having an annular planar surface lying generally in a plane converging at an acute angle to a plane normal to the axis of the through-bore and generally complementary to the plane of said valve seat, said planar surface of said body member being surrounded on its radially outer periphery adjacent its upper portion by an arcuate shoulder terminating in circumferentially spaced ends and extending axially from the body member, said planar surface being further provided on its radially inner periphery by an annular shoulder extending axially from the body member, an annular resilient seal member received on said planar surface and bounded by the annular shoulder and the arcuate shoulder, said annular seal member being generally rectangular in radial section and having an upper bulbous portion extending axially there-from for engaging the upper portion of said valve seat facing the other of said ports, said bulbous portion of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness of said seal member at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position, and said bulbous portion of said seal member preventing the lower portion of said seal member from dragging across said edge of said seat when said gate member is opened and closed;
means for retaining said seal member on the body member of said gate member; and valve stem means operatively connected to said gate member and extending through said valve casing, said valve stem means being operative to move said gate member between the closed and opened positions.

2. A gate valve structure as claimed in claim 1 including means to orient said annular seal member on said planar surface of said body member during assembly with its bulbous portion having its thickest radial section positioned in a plane extending normal to the body member and through the axis of movement of the gate member at the top of the planar surface.

3. A gate valve structure as claimed in claim 2 wherein said orienting means includes a radially inwardly projecting tab on said annular seal member and a recess provided in said annular shoulder for receiving the same.

4. A gate valve structure as claimed in claim 3 wherein said recess provided in said shoulder is offset circumferentially from a vertical and a horizontal axis through said planar surface and wherein said tab on said seal member is similarly offset whereby said seal member can be installed on said body member in one position only.

5. A gate valve structure as claimed in claim 1 wherein said seal member is provided with an annular reinforcing ring interiorly of the same and said means for retaining said seal member on the body member of the gate member includes circumferentially spaced screws extending through the reinforcing member into the body member of said gate member, said screws being capable of individual adjustment to cause said retaining ring to apply pressure at discrete positions on said seal member.

6. A gate valve structure as claimed in claim 1 including means on the body member of said gate member to accommodate for flow of said seal member in an area adjacent to the circumferential ends of said arcuate shoulder whereby said seal member avoids having its valve seat engaging portion damaged upon closing of said valve and axial compression of the upper portion of said seal member.

7. A gate valve structure as claimed in claim 6 in which said means includes recesses in said planar surface of the body member adjacent the circumferential ends of said arcuate shoulder.

8. A gate valve structure as claimed in claim 1 in which the acute angle of the upper planar portion of said valve seat is substantially in the order of 10 degrees, and wherein said annular resilient seal member has its bulbous portion arranged for wedging action with the upper planar portion of the valve seat upon closing of the valve with a remainder portion of the seal member being compressed by closing action of the valve.

9. A gate valve structure as claimed in claim 8 including providing a relief surface in said chamber upwardly and outwardly of said planar portion of said valve seat at an angle greater than the acute angle of said planar portion of said valve seat.

10. A gate valve structure as claimed in claim 9 including a pair of oppositely disposed groove-like guideways within said valve casing and extending from said through-bore into said chamber, a pair of oppositely disposed ears projecting from each side of said gate member and arranged in said guideways to guide said gate member during opening and closing movement of said valve, said ears and said guideways having a width dimensioned to ensure wedging action of said seal member during closing regardless of direction of the flow of fluid through said through-bore.

11. A gate valve structure as claimed in claim 10 in which said ears extend substantially to the bottom of the body of said gate member whereby rocking of said gate member during opening and closing is substantially eliminated.

12. A gate valve structure for use in mains carrying a fluid, said gate valve structure comprising:
a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through-bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar portion facing toward the other of said ports except at a bottom portion thereof where it merges into and forms a portion of said through-bore;

a generally flat gate member reciprocable in said elongated chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member having an annular planar surface lying generally in a plane converging at an acute angle to a plane normal to the axis of the through-bore and generally complementary to the plane of said valve seat, said planar surface of said body member being surrounded on its radially outer periphery adjacent its upper portion by an arcuate shoulder terminating in circumferentially spaced ends and extending generally axially from said body member, said planar surface being further provided on its radially inner periphery by an annular shoulder extending generally axially from said body member, an annular resilient seal member received on said planar surface and bounded by said arcuate shoulder and said annular shoulder, said annular seal member being generally rectangular in radial section and having an upper bulbous portion extending axially therefrom for engaging the upper portion of said valve seat facing the other of said ports, said bulbous portion of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position;
means for retaining said seal member on the planar surface of said body member of said gate member;
means on said body member of said gate member to accommodate for flow of said seal member in an area adjacent to the circumferential ends of said arcuate shoulder, said means including recesses in said planar surface of said body member adjacent the circumferentially spaced ends of said arcuate shoulder whereby flow of said seal member is accommodated to avoid said seal member having its valve seat engaging portion damaged upon closing of said valve and axial compression of the upper bulbous portion of said seal member; and valve stem means operatively connected to said gate member and extending through said valve casing, said valve stem means being operative to move said gate member between the closed and open positions.

13. A gate valve structure as claimed in claim 12 including means to orient said annular seal member on said planar surface of said body member during assembly with its bulbous portion having its thickest radial section positioned in a plane extending normal to the body member and through the axis of movement of the gate member at the top of the planar surface.

14. A gate valve structure as claimed in claim 13 wherein orienting means includes a radially inwardly projecting tab on said annular seal member and a recess provided in said annular shoulder for receiving the same.

15. A gate valve structure as claimed in claim 14 wherein said recess in said shoulder and said tab on said seal member are oriented in a position whereby said seal member can be installed on said body member in one position only.

16. A gate valve structure for use in mains carrying a fluid, said gate valve structure comprising:
a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar portion facing toward the other of said ports except at a bottom portion thereof where it merges into and forms a portion of said through-bore;
a generally flat gate member reciprocable in said elongated chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member having an annular planar surface lying generally in a plane converging at an acute angle to a plane normal to the axis of the through-bore and generally complementary to the plane of said valve seat, said planar surface of said body member being surrounded on its radially outer periphery adjacent its upper portion by an arcuate shoulder terminating in circumferentially spaced ends and extending generally axially from said body member, said planar surface being further provided on its radially inner periphery by an annular shoulder extending generally axially from said body member, an annular resilient seal member received on said planar surface and bounded by said arcuate shoulder and said annular shoulder, said annular seal member being generally rectangular in radial section and having an upper bulbous portion extending axially therefrom for engaging the upper portion of said valve seat facing the other of said ports, said bulbous portion of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position;

means for retaining said seal member on the planar surface of said body member of said gate member;
means to orient said annular seal member on said planar surface of said body member during assembly with its bulbous portion having its thickest radial section positioned in a plane extending normal to said body member and through the axis of movement of said gate member at the top of said planar surface, said orienting means including a radially projecting tab on said annular seal member and a recess provided in one of said annular shoulder and arcuate shoulder for receiving said tab.

17. A gate valve structure as claimed in claim 16 wherein said radially projecting tab projects inwardly of said annular seal member and said recess is provided in said annular shoulder.

18. A gate valve structure as claimed in claim 17 wherein said recess provided in said shoulder is offset circumferentially from a vertical and a horizontal axis through said planar surface and wherein said tab on said seal member is similarly offset whereby said seal member can be installed on said body member in one position only.

19. A gate valve structure for use in mains carrying a fluid, said gate valve structure comprising:
a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through-bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar portion facing toward the other of said ports except at a bottom portion thereof where it merges into and forms a smooth and uninterrupted portion of said through-bore, said planar portion of said valve seat having an outer arcuate edge;
a generally flat gate member reciprocable in said elongated chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member provided with an annular planar surface, an annular resilient seal member being received on said planar surface of said body member, said annular seal member having a surface for engaging the planar surface of said body member, said surface of said seal member being provided with an annular bead to ensure a seal with the planar surface of said body member when said seal member is held on said body member, said annular resilient seal member further being generally rectangular in radial section and having an upper bulbous portion extending axially therefrom for engaging the upper portion of said valve seat facing the other of said ports, said bulbous portion of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness of said seal member at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position, and said bulbous portion of said seal member preventing the lower portion of said seal member from dragging across said edge of said seat when said gate member is opened and closed;
means for retaining said seal member on the body member of said gate member; and valve stem means operatively connected to said gate member and extending through said valve casing, said valve stem means being operative to move said gate member between the closed and opened positions.

20. A gate valve structure as claimed in claim 19 in which said annular seal member includes a rigid annular reinforcing ring embedded therein and said means for retaining said seal member on said body member includes circumferentially spaced screws extending through the reinforcing ring into the body member and capable of individual adjustment to cause the reinforcing ring to apply pressure at discrete positions on said seal member.