LU83418A1 - GATE VALVE - Google Patents

Description

The present invention relates to a gate valve, of the type comprising a body having a generally horizontal cylindrical flow conduit which derr-nit a seat surface, and a shutter provided with a bead 5 made of elastomer and guided in vertical translation, this cord, applying to the seat surface of the body and having the same general shape as this.

Conventional gate valves of this type have a generally firm sealing line at this corner.

- 10 They must firstly have an axial dimension compatible with the differences between flanges imposed on the pipes, and secondly ensure reduced wear of the elastomeric lining during repeated opening-closing operations.

These two conditions are antagonistic: to decrease the wear of the lining, it is necessary to reduce the friction of this lining on its seat necessary to obtain the desired compression of the elastomer, and therefore to decrease in each painted stroke the 1 ' seal 20 between the moment when the lining touches the seat and that when the considered compression is obtained. To do this, it is necessary to increase the angle that the surface makes of this seat with the direction of movement of the seal, but unfortunately, this increasing increases the axial size of the gate valve.

The Applicant has proposed a solution to this problem in the French patent r. ° 71. 16057 and its certificate of addition nc 72. 11641, published under ncs 2 12? 615 and 2,178,457.

according to these documents, on either side of a plane of symmetry passing through the axis of the operating rod and perpendicular to the axis of the outlet pipe, those 2

In the various variants of this patented valve, each adjusted surface forming a seat on either side of said plane of symmetry comprises a curved portion greater approximately transverse to the flow axis, a lower curved portion merging with the cylindrical internal surface of flow, and between the two, above and below a "! diametral zone represented in projection by the flow axis, an intermediate portion of transit approximately 10 helical in the form of a rotating ramp which connects said upper and lower portions by bypassing the cylindrical flow surface, as close as possible thereto.

This regulated surface, that is to say formed by 15 rectilinear generators, has a mean sealing line which is a closed curve. At any point on this sealing line, the plane tangent to the seat surface (plane formed by the straight generator and by the tangent to the sealing line in this picture) 2G makes an angle at least equal to a predetermined angle , which is for example 20 °, with the direction this translation of 11 shutter or axis of the operating rod.

Along a sealing zone extending over more than half of the sealing line, the angle i 2Ξ between the tangent plane at each point of the sealing line and the axis of the rod maneuver is almost constant.

The lower generators of the flow tubing may be straight or may include a deflection closing a recess or a projection on which or on which the lower part of the shutter is applied.

Thanks to this arrangement, the sealing contact g * -. * - »- g; 1- seat and the shutter tar 2'intermediate of 25 the carniturs rubber seal is fully "ï *. *: * »

O

continuous over the entire closed contour of the seat, in such a way that the gate valve is rigorously tight in the closed position, even and r.cterrent in said intermediate transition portion of the sealing surface.

I open, thanks to the aforementioned minimum angle of 20, the sliding of the seal over the century when I close the closure of the cover is significantly reduced compared to that which is put back into the taps! 'previous. This results in less wear and tear on the shutter seal.

The invention aims to provide another! solution compatible with the previous one and due avantaceu— had painted in view of the efzort necessary for the opening I 15 of the cover.

I To this end, the subject of the invention is! gate valve of the aforementioned type, characterized in that the I sealing line of the seat has, seen perpendicular to

! the axis of the flow duct, a general X shape

I 20 and is obtained, over all or practically all of its length, by translation towards one another, along said • j axis, of two sealing half-lines before one; general corner farm.

] In one advantageous embodiment, which | 25 ensures a minimum, axial bulk, each half »surface of §manchsite is such ~ ue defined in patent FR 71.16 057 or in sen certificate c'addition 72.11 641, and recalled above fasen summary.

<„In this case, to simplify the faLrrcaticn, | 30 the part of each half-sealing surface located above the zene of the flow axis wants to be replaced-ij c ^ ~ by two portions of pian eu- vercsrr.t towards this axis and f p. .c-.cnçs = es by surueces curves of connection to <areas above 4

When in the lower portion of the seat, the anal ••• I do with the axis of the rod this maneuver the plane! Ance at the sealing surface varies, advantageously, the crest line of the sealing bead is defined 5 üa so as to simultaneously approach the seat surface

Dn all its pointed "except dnns Here Doiruiou xnfSirisuirö άθ cstts * uxfâcerou, loxs iis this p2reni.02T contsctr remains a ladial game which gradually increases on each side to the bottom moint of the flow cavity.

1 "Thus, during the shutter closing phase,

Years after the sealing contact between the shutter and i = iëge has been made on most of the cord o'étancnsxta, except on 1adire lower part, the intervals between sealing cord and seat, which will cross 15 " ant on the lower loops of each sealing line away from the diametral plane of the flow pipe, gradually reduce, and the sealing contact is made gradually, also followed ”; '' progressive compression of the seal this sealing. 22 chard nc-ns im.ultsnëi t sealing contacts around the entire perimeter of the sealing line and this progressiveness of the coming into contact with the seat and the radial or normal compress-vicn of the cord had the seal compensate at least partially, in the direction of 2 "3 1'uniformité the crushing of the cord at the end of the shutter closing stroke, the variation of the angle oL eue ram with ι ', - .xe de xa rod ce maneuver the oisn tangent to the sealing surface the lene of its middle lions in the lower portion ce the seat surface- 20 We can obtain a total or almost total uniformity of the crushing of the cord when said game evolves according to a law of the type! = a sine -n, cl a and b are censtants.

This can be achieved in this simple way, in the case of a flow duct with circular section, by giving the lower part of the bead, seen along the flow axis, a circular shape of ragten greater than that of the flow cavity.

3

To hold these manufacturing elements together, it may be desirable for the points of this X crossover to be rerr.p_ by these nopiats on the surface this siece gu, on the sealing urch, by segments this straight a roughly vertical in lateral view.

5 In the case where the flow tubing is present at the top of the shutter in an internal or external projecting region, the lower part of the seat surface is modified in a corresponding manner, with surfaces of progressive connection to the rest. this this 10 surface.

The invention is described below in more detail with the aid of the appended drawings, which show only certain embodiments thereof. In these drawings: FIG. 1 is a longitudinal section view of a gate valve according to the invention with an outlet. shutter in the closed position and shown in external view, the upper part of the gate valve not being FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, that is to say in the transverse plane of symmetry of the gate valve; Fig. 3 is a view in longitudinal section similar to FIG. 1 of the gate valve without its shutter, this view illustrating the seat;

X3I Tick. 4 0Stl \ 2V Θ ^ “j, SVC

taken along line 4-4 in FIG. 2; Figs. 5 to 5 are these views similar to FIG. S is a sectional view taken along line 9-9 of FIG. 5, with partial removal; ί ο Ι the Proud, it is a schematic perspective view of the shutter of the embodiment of Figs. 4 to 10; Fig. 12 is a perspective view of the sealing line according to this second embodiment; Figs. 13 and 14 on the one hand, 15 and 16 on the other hand, feel partial views in section along a diametral plane passing through the flow axis, illustrating two modes of assembly according to the invention of two half-10 lids can form a single shutter, these figures. illustrating in section the assembly means and the seal in its lower part; Fig. 17 is a partial sectional view taken in a horizontal plane situated a little below the flow axis, showing the configuration of the upper part of the half-caps; Fig. 15 is a simplified cross-section illustrating the angle of the planes tangent to the surface I c'étar.creite with the direction of the operating tics, J 20 in the lower part of connection with the surface cvXiGGiricriiG g 1 ôcoulsinsnt zrspirëssnliës psit un cg ^ tcXs Fig. 19 is a sketch, in elevation and in plan, illustrating the sealing line of a following gate valve: the previous patent FR 71. 16 067 of Application-25 resse; | Iss Fig. 20 and 21 are similar diagrams * c in FIG. 19 showing, for comparison, the lines of severity of the two embodiments of the present invention; Fig. 22 is a view in longitudinal section c a variant of the body of rcbir.et — valve according to 11 inver— I L.icn, in the case where the flow pipe has a | legem.enn hollow, vertical walls, part u férié u-; re ce ia ccurse of the shutter; i t ί _ i> “7 / Figs. 2 3 and; 24 are half-views taken: respectively in section along lines 23-23 of the

Fig. 22 in 24-24 of the Fie. 23; the Fie. 25 esr a view in ccupe lonçitudina-; ' 5c of another variant similar to that of FIG. 22; , but or the hollow pocket, instead of being connected to the: - ruoulure c 'cornered by vertical oarois- / is connected to this tubing by these inclined walls; Figs. 26 and 27 feel these half-views in section taken respectively according to the files 26-2 6 ce la ^ icr *? 5 p- 9 7-0 "7. — 4o. * 1 = ν-rr.

, - ^, ucr Xa. i iç, f i ‘fig. 2S is a view in longitudinal section S, f of another variant similar to that of FIG. 22 but

iV

! ' the lower generators of the flow tubing: ^ menu have a d-viaticn forming a projection inside this tubing; Fig. 29 and 3G are half-views in section | l taken respectively according to files 29-29 ce la || Fig. 28 and 30-30 of Fig. 29; and! '20 0 Figs 31 to 34 are views similar to: ·: 1 Fig. 5 to- 6 respectively / relating to a variant of the second embodiment of the invention.

r

Fia.35 is a partial longitudinal sectional view of another embodiment of the 25 "gate valve.

according to the invention; Fig. 36 is a view of this crisis gate valve in cross section along line 36-36 of Fig. 35; the Fie. 37 illustrates in longitudinal run 30 '_ of the cord the first contact of this corccn with the seat; . \ the Fia. 38 is a view taken in section along line 38-38 of FIG. 37; s Fig, 39 is a view similar to Fig.38 but corresponding to the complete closure of the shutter; FIG. 40 shows in cross section of the cord the contact of the latter with the seat at the low point 5 of the flow conduit; and Fig. 41 is a view similar to FIG. 40> but corresponding to the complete closing of the shutter.

The rohinet-yanne illustrated in Figs. 1 to. 4 10 comprises a body 1 in the form of a T molded in cast iron or in another metallic alloy, or also in plastic material, The body 1 comprises a tube 2 of axis XX of inlet and outlet of the transported fluid, this tube 2 being intended to be connected, for example by flanges, to a pipe not shown, and a tubular cage 3 of axis YY perpendicular to the axis XX and closing the pole of T. For the purposes of the description, assume the horizontal axis XX and the vertical axis YY, the cage 3 extending upwards from the tube 2, Only the lower part of the tubular cage 3 is shown; its upper part comprises, as known, a cap closing the body and serving as a watertight guide to t i ^ * î ï! 9 The tubing 2 has an inner cavity 4 of cylindrical circular cross-section while the tubular cage 3 has an inner cavity 5 of axis Y-Y also cylindrical but of section approximately eliipti-; '5 that. The cavity 4. is interlocked in the extension f 1 of the cage 3 by a seat surface 6 of particular shape 1 lier described below.

i | 'On seat 6 is intended to be applied,! by translation between an open upper position and I 10 a closed lower position, a shutter or cover I! the 7 maneuvered by a tice this threaded maneuver 8 of axis Y-Y. The upper end of this threaded rod is mounted mobile in rotation but motionless in translation in the upper cap of the body 1, and its lower end 15 cooperates with a nut, this maneuver not shown, which is trapped in an upper cage 9 that the shutter . Like the body 1, the shutter 7 admits as planes of symmetry the vertical plane Q containing the

; X-X and Y-Y axes and the vertical plane? containing the Y-Y axis

, 1 3 20 and perpendicular to the X-X axis.

1 The shutter 7, described below, can be made of any suitable material such as gray cast iron, I 'cast iron a. spherolcal graphite, steel, cuprcalliage, I plastic, and can be made by any! 25 appropriate technique (no precision, metering, machining, etc.). In this example, the shutter is hollow 1 and made up of those half-epcrcules 7th and 7 ~ assembled 1 as will be seen below and entirely coated with rubber I.

30 The shutter 7 has a general closure this plate oeroer.dicular to the axis XX ad act with dimensions es fi - - j, 1 c "” 'î_ΓιG. ^ ^ 4 --- ur * * ^^ "ΌΠ ^ 12 X a ,, -. utc. trCct O Hv ·· —- ο GL.Tllu: _hti.m 1 / "ii - '^ 10 tubing 2 in order to apply tightly to the seat 6. It has at its upper part, in addition to the cage 9 trapping the nut of the operating rod 8,, two pairs of ribs having lateral guide lugs 5 10 parallel to the axis YY and situated on either side of the vertical plane Q.

The ribs 10 of this guide cooperate with two vertical guide ribs 11 located on the plane of symmetry P of the gate valve, inside the cage 3 and projecting with respect to the cavity 5 thereof.

Two modes of execution of the surface of this seat 6 and of the shutter 7 will be described below.

- First embodiment of the seat and the shutter (FIGS. 1 to 4 and 2C) I "“ 15 The firmness of the seat 6 is deduced directly from that described in the aforementioned patent of the Applicant FR 71.16 057, as see it by comparing the diagrams these Fiç. 19 and 20.

According to this patent FR 71.16 057, as illus- tr = geometrically in FIG. 19, the transverse profile of the seat, or more precisely the projection of the curved and continuous sealing line on the plane of symmetry Q, is represented by the lines A, B, D, C and A1, B1 / "D, C . This profile consists of two symmetrical curves with respect to the plane P and has the general shape of a ship's hull. We recognize the upper curve portions A, E and a \ transverse with respect to - the X-Y axis of flow, c1 is practically vertical wax - "it

ca_es, the lower portions of this curve D, C and D ‘, C

30 which merge with the trace of the plane P and feel entirely situated on the cylindrical flow cavity A, and the intermediate portions this transition E, E, D and „1 _ i -i - / - t D * which feels helical, which intersect the axis XX at B and B * and which connect the upper transverse portions 35 to the lower portions of each half-111 sealing line. Lines A, B, D, C and A, B ^, D, C1 are the projections of the mean line of seat 6, which is made up of two regulated surfaces whose generatrices are orthogonal to the axis X-X in; 5 upper portions A, E and A, E, parallel to the axis S XX in the lower portions combined D, C and D ^, i 1 ", C * and of evolutionary orientation between the perpenarcularxte and parallelism, like the steps of a spiral staircase, in the intermediate portions E, B, D and

It i "* 1 10 E, E * and D1.

It is also recalled that the sealing lines A, E, 3, D and E1, B *, D1 admit at all points a plane tangent to the seat surface 6 which forms with the axis Y-Y an angle ¢ ^. roughly equal to a prede-L value

15 finished, for example at 20 ° (tangent planes of traces, T

? 1 and K “, T in FIG. 1S). Then, from D to C and from D to j 0 ^, the angle oc gradually evolves from the minimum value | male 20 ° to 90 °.

| The upper part of the diagram in FIG. 20 20 is the projection on the same plane Q of the sealing line of a tap according to the present invention. Curves A, E, B, D, C and A.2,, Β “, ο2, ζΓ are identical respectively to curves A, E, B, D, C and A1, Ξ1, B1, D1, C1 in Fig . 19 and have the same portions 2 n 2 -> 25 upper A ", E, A, E“, lower D, C and Ώ, C “, * and transition and connection intermediaries between the upper portions and the lower portions E , 2 Ί '9 B, D and Ξ “, B", D ", and correspond to the same geometrical definitions, and it is the same of the conditions on 3C the planes tangent to the surface this seat along these curved ones.

But, in order to reduce the maximum longitudinal space requirement of the seat (distance A., A "" and A., A. “in Figs. 19 to 20) ', has compared it by translation parallel-35 menu to the axis XX those symmetrical curves, this way a / / that they cross in B or B2 (Fig. 20) on the axis XX.

12

It follows that the maximum longitudinal dimensions A, 2 A with respect to: at the axes X — X esc ind S the previous dimensions A, A, the reduction in the dimensions being 5 equal to the magnitude of the translation considered.

Consequently, the sealing surface 6 admits an average sealing line 61 which, in projection onto the plane Q, constitutes the set of curves A, E, B, D, C and A, E, B, D, vs. Line 61 of sealing -; 10 tee is illustrated in Figs. 3 and 4 by a dashed line carried on the seat surface 6 and is embodied by the ridge 71 of an elastic sealing bead 12 carried by the shutter 7, this ridge having exactly the same shape. Line 61 is constituted by the set of two lines which intersect at the ends of the horizontal line of the pipe 2, on the axis X-X. The portions of each half of the sealing surface 6 are, correspondingly: - two upper portions 62, situated approximately in a plane transverse to the flow axis XX, corresponding for the line of tightness to A, E, 2 2 and A, Ξ; - two upper intermediate transition portions 63, helical, situated above the diametrical zone 25 of the flow axis, corresponding to E,? ? B st E ", B“; - two lower intermediate transition portions 64, horizontal, located below the diametrical zone that the flow axis XX and the other 30 side of the vertical plane? Relative to the previous , corresponding to B, D and Eh D “; and - those cylindrical lower portions 65 merging with the flow cavity 4 and parallel to 2 the axis XX of flow, corresponding to D, C and D, 7: z , o “- 'mJ V_. * / /} i 112

All these surface portions are connected in this continuous manner to each other: and to these surface portions on the seat correspond portions of the sealing gasket 72 to 75, respectively, on the sealing bead 12 from cover 7.

The sealing lines 61 of the seat 6 and 71 of the cover 7 thus have, in side view, a general shape in X. Each half-line situated on one side of the plane P has a cusp point B at each end 10 of the horizontal diameter of the flow pipe 2. Likewise crossed sealing surfaces are obtained on the diametrical zone of the flow axis X-X; above this diametral zone, the surfaces, flared at the top, converge towards the diametral zone of the axis X-X. Below this diametrical zone, the sealing surfaces converge from the lower part towards the diametrical zone of the axis X-X.

In other words, the portions of surfaces situated above the diametral zone of the axis XX and 20 on one side of the plane of symmetry P extend below this diametral zone and on the other side of said plane of symmetry P. It is this extension which ensures continuity, despite this geometric discontinuity marked by the cusp point B for the portions of. 25 sealing surfaces located on the same side of the plane of symmetry P.

As shown in perspective in FIG. 12 for an alternative embodiment described below, the sealing line 61 71 is in reality a closed curve. 4, with t 2 - - f those painted this reoroussement Ξ, 3 s yme triques with respect to the plane of symmetry Q containing the axes XX and Yy (plane i of Figs. 1, 3 and 2D). Lines 61 and 71 merge into J 35 in the closed position of the gate valve.

14

On the shutter 7 {Fig. 11), the bead 12 d1 sealing, of approximately circular section, evolves author of a shutter nlsteau 76 whose mean plane is the plane Q and comprises a lower part 77 of thickness (that is 5 to - say dimension along the axis XX) constant and semi-cylindrical whose horizontal diameter is located above the flow axis XX, then a part; intermediate 78 parallelepiped of the same thickness, then a wedge-shaped upper part 79 whose a-10 ridge crosses the axis XX at a right angle and which diverges upwards to the upper loops of the sealing line 71. The corner has at its upper part a dimension along the axis XX greater than that of the intermediate and lower parts of the plate 76. The lateral guide lugs 10 feel protruding from the corner 79 on either side of the plane P .

The sealing bead 12 follows the entire edge of the corner 79 as well as the lower part of the semi-cylindrical region 77, at each axial end thereof. From there, the two lower curved portions of the sealing surface meet at the vertices of the corner 79 by converging towards the diametrical zone of axis X-X.

According to Figs. 2 and 4 of the shutter and the seat taken in the transverse plane of symmetry P, the different portions of the sealing surfaces extend symmetrically with respect to the plane Q, in the plane P, along arcs having the approximate values following on each side of the plane of symmetry P, so count twice: 30 a) 62—12: about 60 °; b) 63-73: around 30th; c) 64-74: approximately 30 °; d) 65-75: around 60 °.

We will see later the mode which was carried out by the shutter 7, which is common to the first and to the second shutdown mode.

/ 15 - Second mode of execution (Fig. 5 to 12 and 19):

To better understand the constitution of the second execution method compared to the first / on! compare the diagrams of Figs. 20 and 21.

1 5 While maintaining the principle of lines; and crossed sealing surfaces, we have, for the sake of simplification, replaced the portions 62-72 and 63-73 (or 2 2?. A, E, B and A, E, B) located above the metric zone of axis XX, that is to say the upper portions Si 10 and upper intermediates..in continuous curvature, of helijoidal evolution, by two convergent planes of rectilinear trace i 3 Λ 1 2; A, F, B and a “, F, B“ (Fig. 21), the half angle at the top “<. being greater than or equal to 20 ° with respect to the Y-Y axis.

Below the diametrical zone of the X-X axis, the surfaces and sealing lines of the first embodiment have been kept.

", I; It can be seen that this simplification in the upper area of the surfaces and sealing lines is obtained at the cost of a slight increase in overall dimensions! 20.

Maximum ruin for the same angle, because the distance î.3 4, 2

r a. of Fig. 21 is greater than distance A, A

Qe Fig. 20. But this maximum longitudinal dimensions: CeSue all the same less, for the same angle c <, to I. -> 5 ° elui clu anterior valve-valve (distance A, A "* - from 19).

More specifically, in this embodiment, 1 a

Upper part 62 of the seat is constituted by: "two semi-elliptical flat surfaces 62a which are 3q Iss intersections these two convergent planes symmetrical with respect to the plane V with the park! Ce la tubu-

»I

^ iure 2. These semi-elliptical surfaces extend if I from the junction between the tubular cage 3 and the • tubing 2 to an area located approximately halfway; 3 $ tutor between the horizontal plane passanz

Via the X-X axis and the golden j. c zi on between the tunular cage î

IS

3 4 1 3 and tubing 2 (segments Ä, F and A,? In Fig. 21); - two intermediate regulated helical surfaces 63a extending up to the aforementioned diametrical plane, corresponding to the portions F, B and F, B of FIG. 21. These surfaces 65a ensure the gradual transition with the two lower transition surfaces 64.

! The two lower transition surfaces 54 feel, as in the first embodiment, left surfaces extending from an area located at the axis XX to about halfway between the axis XX and the lower generatrix of the cavity 4. These are left surfaces in the shape of this rotating ramps, that is to say regulated helical surfaces, generated by generators supported on a curve of intersection of the surface 6 with the cylindrical flow cavity 4. The surfaces 64 exhibit an evolution of rotation around a vertical axis when one follows their curve of intersection with the cylindrical cavity. The surfaces 20 63a and 64 admit at all points of the median line or sealing line 61 a tangent plane which makes with the axis YY a minimum angle of 20 °, this angle gradually increasing up to 90 ° in the lower part , where the surfaces 64 are joined to the surfaces 65 combined with the cavity 4.

The central sealing line 61 of the seat surface 6 is, as previously, made up of two lines symmetrical with respect to the plane of symmetry P of the gate valve. These are shown in the top view of FIG. 9 and on the lower part of Frg. 21; they are closed and continuous but present significant changes to this layout or direction (cusps) on the layout of the plan? The rigr.e 61 is also shown in perspective in FIG. 12. As before, it is along this line λ

Ls "17 id * seal 61, common to seat 6 st 1 shutter 7 (line 71 identical) that the seal of the shutter 7 is applied to the seat 6.

In projection on the plane Q (Figs. 5 and 7), 5 the links 61 make an X c in s 111 u— c il. V a point downward suoertosé has an inverted ü in-sr ^ sur, “while in the first embodiment this embodiment the upper vT is. replaced by a higher U.

In the projection plane P which is that of FIG. 6, the sealing bead 12 and the sealing line 71 only appear in the upper sealing part 62, 72 under the cast of a half-ellipse, on a part of the intermediate zone 63, 73 and on the lower part 65, 75, while they are masked on the part 64, 74.

We will now describe the constitution, in the two embodiments above, of those parts 7e, 7 ^ of the shutter 7.

These parts 7a, 7 ^ are constituted by reinforced thin shells (FIG. 13), that is to say thickened at 13 on the side of the shutter, at the level of the axis XX, so as to have at these locations of the assembly means constituted by a pair of conical studs 14 projecting on a half. 25 cover (for example 7a) and fitted into the conjugate conical recesses 15 of the other half-cover (7 ").

. . There are also internal projections 16 of reciprocal ap one on the other (Fig. 17), located both on the lids 7a and 7b and constituting 20 er.tretoisa ^ qu ^. avoid the crushing of thin walls of the sealer 7 during the application by molding of a coating or lining of rubber 17 which is injected under pressure into a mold containing the ob tu-s

From p-ius, against gold. ge sees at the Fie. IG, the 3— C6U- “. 3.2Γ - icîs j i co *, ipor i.nizéïri.euïr & iriS ^ ti g.—

\ W

18 ”internal lugs 1S originating on a cover 7 having resting on the upper internal wall, horizontal, that the other cover 7 °, and vice versa, just below the nut cage 9, crossing the plane of joint P. These pins - are used to avoid any separation by shears - * 3. b holds lids 7, 7 / during the closing operation, if a foreign body obstructs only one side of the plane P of symmetry.

The rubber seal 17, ZZ of variable thickness, is thickened to form the sealing bead or crest 12 materializing i "i-'cne sealing 61 and is thinned in the plane of symmetry PP or plane d 'assembly of the lids 7a, 7S. tS3 two sb lids 7, Ύ are coated independently, one this 25 the other, over their entire surface, internally and externally, including on the supporting projections 16 and the studs 14, by the seal 17 They are joined together with an adhesive product, therefore without bolts. Only the top of the studs 14 and the bottom of the recesses 15 has no coating.

By their firmness, each of the ooercules 7a, 7 constitutes an object without undercut therefore moldable without core.

We note, by comparing Figs. 12-14 and i 15 15-16, that the crest 12 of the seal 17 can be divided into two symmetrical parts on the chapered cap 7a, 7 ° (Fig. 13-14} or else does not exist on a single cover, 7 for example, the other cover 7a being correspondingly truncated (Fig. 13-16) so that the joint 2I joint forms in this zone a baffle with a right ancle opposing possible introductions of fluid between the two covers.

We also note, by comparing the section in FIG. 1 "to that of FIGS. 12 to 15, that in the zz- upper portion g 'etraneneaue and below the diametrical zone 19 i) of axis XX, the sealing bead 12 is oriented differently; bead 12 located in the lower portion; in; the latter, the bead 12 is applied to a surface close to or coincident with the cylindrical cavity 4! 5 while, at the upper levels, it is applied to a bent surface -! roughly · transverse to ane'ane XX, horn described above..By, sa,! the cord 12 is everywhere directed towards the surface 6.

The shutter 7 shoeed by the glued assembly; , ab of the lids 7 ^, 7 concerted on its periphery of the surfaces. 10 these convex conjugate concave surfaces forming the d ~ c ± r- * CL · i 'Alternatively, the shutter 7 may be monoblcc, but its molding is more difficult than er. two parts.

; We will now consider the projections; 15 horisesaies of the sealing lines of the gate valve according to the invention (Fig. 20 and 21) and of the gate valve \ according to patent FR 71.16 057.

Under the effect of the upstream or downstream pressure of the fluid transported, the shutter 7 in pooioion this closure 20 is applied to the part of the seat 6 opposite this pressure, eo; the sealing line 61 is A, E, C {Fig. 20 and 21), in I projection on the sectional plane Q of FIG. 5.

j. If we project this sealing line on

Ile diametral plane passing through the axis X-X and perpendicular to the axis Y-Y, one obtains for the second embodiment this 1'invention the hatched surface, increasing, that the% Dartre lower of the Fie. 21. This surface represents i J the surface according to which an error must be exerted I can open the shutter and overcome the pressure of the fluid j | 30 that he undergoes. The resistance to overcome for opening the shutter t is called the bottom effect. This resistance to this background is the result of the pressure to be overcome by the projected surface, hatched in FIG. 21.

i1 Or. sees therefore that this background effect or this resistance to Γ 35 defeat is all the more important, for the same) i l; ! / h 20 pressure to overcome, that the projected surface is more imper rance.

It can be seen by comparison that the surface projected in FIG. 20, for the shutter 7 of the second embodiment 5 of the inventron, is significantly reduced compared to that of the shutter according to the applicant's prior patent no. 71.16 057 (chained etan-7 line and hatched projected surface of FIG. 19), with equal diameter of the flow conduit 4 of course.

10 Numerical example:

For an internal diameter of the flow cavity 4 of 150 mm, and for a pressure of 15 bars to overcome at the opening of the shutter, the projected surface {Fig. 19) of a shutter according to the aforementioned prior patent o 15 of the Applicant was 250 cm "and the opening force or bottom effect was 4000 kg.

For a shutter according to the second embodiment of the invention, the projected surface is reduced to 50 cm 2 (Fig. 20) and the effort to be overcome during the opening is reduced to 800 kg.

We notice in Fig. 20 (projected area for the first embodiment) an even smaller projected area than that of FIG. 21, therefore a fortiori lower than that of FIG. 19 correspon- * 25 dar.t to the front gate valve.

Thanks to this appreciable reduction in the background effect, it is possible to use, with the gate valve of the invention, an actuator of lower power and of less ccmbrsment.

20 In addition, the upper part of the sche mas of Figs. 19 to 21 illustrates the reduction in longitudinal dimensions, that is to say the distance between flanges of the pipe 2 measured parallel to the axis Σ-Ι-Ι, with equal diameter of the conduit 4, with respect to a retinst-valve according to the patent pending of the Applicant

If / / ^ '' 21 1 y ·) | n ° 71.16 057, for the same minimum angle between the axis 1¾ X-X and the plane tangent to the sealing surface the ionc c = the sealing line.

Finally, the shutter of the invention retains, 5 thanks to the shape of the seat 6 and to the combined shape of

Ises half-lids 7a and 7 ", the advantage of getting closer or further away from the seat 6 with a minimum of friction because the mistletoe surfaces must apply to each other to establish the seal move one with respect to the other, the other practically without slippage, which advantageously results in the rubber seal 17, and in particular its sealing bead 12, being subjected to the minimum of wear.

In what follows wind will be described laughs of the two previous embodiments. These variants relate only to the lower part of the sealing surface 6 and correspond to the case where the flow pipe has an internal or external projection.

- Variant of Figs. 22 to 24: The tubular body 1 20 has a transverse pocket 20 on either side of the transverse plane P, therefore around the axis YY, constituting a protrusion or external projection at a low point relative to the lower generatrices of the tubing 27 The role of such a pocket 20 is to serve as a housing for the lower part of the shutter at the end of its closing stroke.

This pocket has the shape of a cylindrical ruled surface tooth the genera are parallel to those of the cylindrical cavity 4 eu are connected by u pa ^ .- ~ s paral.lr; _es at pmn P - conceal cavity. In censecruet— ce, the sealing surface of the seat of the shutter is simply changed by replacing ce the lower plenum cvlindrioce 6 ^ because uns ^ __ which merges both with a psrtie ce the cylindrical cavity 4 and with the pocket 20. Consequently, the 22 ′ lower part 66 is a partially cylindrical adjusted surface and partially of elongated shape downwards beyond the cylindrical shape and whose rectilinear generatrices evolve between those of the cavity 45 and those of pocket 20 ,. with which they will eventually merge.

- Variant of Figs. 25 § 27: The tubular body 1 presents, as before, a transverse pocket 21 projecting externally with respect to the tubing 2, but this pocket is connected by chamfers 22 to the cavity 4.

The lower part 65 and the sealing surface is replaced by a lower part 67 which is adjusted and whose rectilinear generators progressively evolve between those of the cylindrical cavity 4 and those of the chamfers 22.

- Variant of Figs. 2S a 30: The tubular body 1 has an internal projection 23 on either side of the transverse plane P. This projection 23 is a regulated surface closing a cylindrical excess thickness of axis parallel to the axis XX and of larger radius that the cavity 4, and it is r ^ cor ^ ep ^ r ^ nanxtexris cj_rcuj_arrss 2¾ to the cylindrical cavity 4.

The lower part of the obturator 7 must be applied in a sealed manner to the internal projection 23 and in particular to the circular chamfers 24. Consequently, the sealing surface of the seat that the obturator is modified by replacing the part cylindrical lower 65 by an adjusted lower part 68 whose generators progressively evolve these Generators 3C this cavity 4 parallel to the axis XX to those of the chamfers 24.

In each of the three preceding variants, the lower part of the shutter 7, and in particular this its sealing line 71, esc yesterday, inmencu modified from the - * “iïdÇon cjti0 lâ s mmecj cê en j 23 that the same variants can be considered for the first embodiment of the invention.

In variants of the Fier. 25 to 27 and 28 ai 3C, it is essential to note that the angle made with 5 1 * are YY the clan cut to the bearing surface 22 or 24 along that the sealing line is at least equal to the minimum angle of 20 ° ai. Along the entire length of the line! at least a constant angle is obtained! "" equal to 20 °. This has the advantage that, over the entire periphery of the seat, the elastic seal 17 works under the same conditions. It is thus i, if the compression that the seal, counted i; perpendicular to the bearing surface, is constant over the entire periphery of the seat, for fear of a given depression 25 that the shutter. If you change the depression of the shutter, this compression will have a good value but will lock in the new uniform value around the entire perimeter of the seat.

These two variants have the other advantage of guiding and supporting the shutter at its lower part at the end of the closure. This is an advantage which is all the more advantageous since the bearing and guide surface of the ears 10 of the shutter on the guides 11 of the body has a limited height.

- Variant these Figs. 31 to 34: Note that in the two execution modes these FIGS. 1 to 4 and Figs. 5 to 8, ’there is a critical point on the sealing line, this I crossing B, B“ which must coincide on the seat and on the seal 17 this 1'embreteur 7.

If the manufacturing tolerances of the seat, dj 30 on the one hand, and of the burner, on the other hand, are wide barter, there is a risk this slight shift this point of 4 - _ - | crossing on the seat and on the shutter, and therefore "i *" • that there is a risk of leakage.

j This is why, in the case where 3a of tears tolerances da fabricaricr. are provided, it is believed that i / i /

j- O

there i 24! replace this critical crossing point with a short sealing line 80 forming a hyphen with vertical lateral projection on the plane Q, This line 80 is materialized by a crest line 81 on the shutter, on the 5 part and d 'other of the diametral plane of axis XX and in the vicinity this one, this crest line being on a small straight segment 82 of the sealing bead of the shutter (Fig. 31}, and by a flat 83 of connection between surfaces 63 and 64 on the seat (Fig. 33).

10 So, a slight shift on one side or the other of the plane of symmetry? -? is possible inks the seat and the shutter, because there will always be sealing contact between the sealing ridge 81 of the straight segment 82 and the corresponding flat 83 of the seat.

15 The gate valve shown in Figs, 35 and 36 has a body 1 identical to that of Figs, 31 to 34. The shutter or cover is generally similar to the shutter 7 of Figs. 31 and 32, the only difference being in the shape of the crest line 171 of I ^ 20 its sealing bead 112 ____-— ..

! / Λ. \ i! ! ! * ► || Indeed :, in the upper and intermediate parts of the cord 112, that is to say by following on each side. At the plane of symmetry P the path P3C2ETG / ridge line 171 has the same shape as line c ' seal 5 61 of the seat, but slightly expanded, that is to say offset at each point by a constant distance or interference i perpendicular to the seat surface 6.

In the lower part of the cord 112, between the two points G which are the upper lim.irss ce the pcr-10 tion of the surface 6 merged with the cavity 4 of the flow conduit 2, the shape of the crest line 171 on the contrary is set back with respect to that of the sealing line 61. More precisely, seen along the flow axis XX (FIG. 2), the lower part of the line 171 15 has the shape of an arc of circle with a radius slightly greater than the radius of the cavity 4 of the duct.

When the seal 1G7 descends to close the conduit 4, there comes an instant t] _ at which all the points of the line 171 located above the two painted G, namely all the points such as A, E, C, D, E, F and G, come simultaneously-menu in contact with the line 61 of the seat (Fig. 7 and 6}. At the same instant ti, there is a radial clearance j_ below those points G, and this clearance gradually increases from a value terà at points G to a maximum value j?. * at the low point H located in the plane of symmetry P, on the axis YY.

When the cover 107 continues to descend from a vertical stroke z to its completely closed position, that is to say above these points G, this bead is crushed 3G gradually: on the surface 6 , without sliding or practicing 26 cio 20 ° eu 303, has all of them painted i = s · s in c / i = w - - V? U · k's i i w w * · Cl ·

Below ring; painted G, in the previous embodiments, the contact 71-SI is made srnultsr.ener.t at time 5 ti, horn above the sentences G. This note in this region the angles vary this ^ 0 to 90th, the interference i = s · sin o <varies from point to point from s. sin c ^ 0 at point G to s · sin 90 ° - s at point H.

On the contrary, on ur vanl. the .t - e · 3 _ · and - ^, we have 10 below the points G: i = s sin - j, so that it was enough to choose: j = s. s.lno <- i0 = s (sin cf- sin ^ 0) '(I) in each oc-int so that the interference i' is still "equal to ie in this lower region. The formula (I) is thus tvoe: i = a sin - b, with a = s and b = s. sin ot

** “O

For example, for ° ^ e = 30 °, the interferences i au ;: painted at and H, at time t2 this complete watertight closure, after a stroke s of 2 mm from time ti and a play in point H of 1 mm at time tl, this is calculated in the following way according to formula (I): - from painted A at point G: i = 2xsin3C ° = 1 mm o - at point H (j = 1 mm) : i = 2 x sin 9 0 ° - 1 =? 1 nan * 25 - at an intermediate point K located below this G and angularly spaced at 30 ° by rappelling at H, at a & * = 60 ° and a radial clearance j = C, 732 mm is required get the same in- Q 2Γ ί 5 i “0 Π C * 3 Γ - - - Ai. -JJ w / / _ - - .. {w L <_ · f / 3 z. - X ITL-i

p. —V

Cn thus obtains interference in ur. overwriting i. which is constant and equal to r0 all around the cord, sealing. This property is advantageous and advantageous because insufficient interference at certain points makes it possible to lead to a leaking seal while there is excessive interference trotting "it - it f - wear of the sealing bead 27.

The formula (I) above, namely j = s.sino (-i6 = s (sinu ^ - sin oC o), gives the outline of the crest line 171 leading to a uniform value iQ of 1 j: 5 over its entire circumference. In practice, it is possible to adopt, below the two points G, an arcuate shape of radius R1 of the line 171 slightly greater than the radius R of the cavity 4, with:

Rl = R + i «10 1 We understand that in the fully closed position, the average line 171a of the crushed surface 171c of the cord 171 coincides with the sealing line 61 of the

J

! seat 6, whereas in the previous embodiments i 25 it is the crest line 71 which, at time t- ,, coincides with this line 61.

The arrangement described with regard to Figs. 35 and 36 can be applied to. all of the above embodiments in which the tangent plane - axis Y-Y angle varies in the lower part of the seat, that is to say in all of the previous embodiments except those of FIGS. 25 to. 27 and 28 to. 30. When the crossing of the sealing half-lines 1 is punctual (FIGS. 1 to 30), the point of intersection replaces the vertical section C, D, E of FIGS. 1 and 2, but the rest Μ 2 ^ of the cord is as defined above.

Of course, the expression "ridge line" - used here must be understood in the larcre sense, this line possibly in some cases wandering a surface of low lar-. - * geur in the case of a sealing bead with rectangular, trapezoidal or half-moon section.

! Throughout this brief, we have assumed! the horizontal X-X axis and the vertical Y-Y axis. However, he ; it is clear that the gate valve that the invention can be used in any desired orientation, by | | 35 example with the vertical or oblique flow axis X-X.

: I

i | Λ; / 6 ^ · | i

Claims (10)

28 * * 1, - Gate valve, of the typa comprising a body having a horizontal cylindrical flow conduit which defines a seat surface, and a shutter provided with an elastomeric sealing bead and guided 5 in vertical translation, this cord applying to the seat surface of the body and having the same general shape as the latter, characterized in that the sealing line (61) of the seat has, seen perpendicularly: the axis (XX) of the flow conduit (4), ur.e general shape in 10 X and is obtained, on any had almost its length, by translation towards each other, along said axis (XX), of two half-lines sealing together having a general wedge shape. 2, - A gate valve according to claim 1, 15 characterized in that the two sealing half-lines cross approximately in the horizontal diametral plane of the flow conduit (4). 3, - Gate valve according to one of claims 1 and 2, characterized in that each half-sealing surface 20 is a regulated surface which has an upper curved portion (62) roughly transverse to the axis d flow (XX), a gatekeeper, lower curve (65) merging with the internal cylindrical surface, flow (4), and in between, above and below a diametral zone shown in projection by the flow axis, an intermediate transition portion (63-64) roughly helical in the form of a rotating ramp which connects said upper and lower portions bypassing the cylindrical surface at most (4) near it. 4, - Variant of the gate valve according to claim 2, characterized in that the part that each half-sealing surface located above the area of the flow axis (XX) is replaced by those / / 1 t * 29 "portions of plane (62a) converging on this axis and extended by curved surfaces (63a) connecting to the surfaces (64) situated below this said zone. 5. A gate valve according to any one of claims 1 to 4, characterized in that the points; X crossing points are replaced by these flats (83) on the surface this seat (6) and, on the seal (12)> by straight line segments (80) roughly vertical in lateral view. 6.- gate valve according to any one of the 5 îC claims 1 to 5, characterized in that the cord! sealing (12) follows the periphery of a plate (76) consisting of a cylindrical lower part (77) with an axis parallel to the flow axis (XX), of a parallelepipedal intermediate part (78) and of a superior part-15 re (79) in a corner farm with a horizontal apex and perpendicular to the axis, of flow. 7, - Robineu-valve according to any one of claims 1 to 6, characterized in that the shutter (7) consists of two half-lids (7a, 7 ^) 20 assembled along a joint plane (P) vertical and perpendicular to the flow axis (XX) / each half Icparcule being a thin shell provided with reinforcing means (16) and this positioning means (14-15) relative to the other half operculum. 25 Gate valve according to claim Ί, characterized in that the half-seal plow (7th, 7 °) has an internal projection (18) which bears against a horizontal end surface of the other half-seal. 30 5.- F. valve-valve according to one of the resellers enter, if the 8, character in this ç§ 7g sealing cord 1 (12) consists of an overspray of a gasket (17) covering all 1'cbturateUr (7). 10, - Gate valve according to claim ctd 9n 33 when it expands from one of these claims 7 c * "" VWWJ 30 "1b characterized in that each half-seal (7,7) is coated on its inner faces and exterior of said lining (17). 11. A gate valve according to any one of claims 1 to 10, characterized in that the flow pipe (2) has, on the obturator (7), an internal (23) or external projecting region. (20, 21), .- and in that the lower part of the seat surface (6) is modified correspondingly, with 10 progressive connection surfaces to the rest of this surface. 12. Gate valve according to one of claims 3 and 4, in which, in the lower portion, the angle made with the axis (YY) of the operating rod 15 the plane cut to the sealing surface varies, characterized in that the crest line (171) of the sealing bead (112) is defined so as to simulately approach the seat surface (6) at all its points except in the lower portion of this surface, where, during this first contact, there remains a radial clearance (j) which gradually increases on each side up to the low point (H) of the flow cavity (4). 13. A gate valve according to claim 12, characterized in that said clearance (j) is obtained by giving. 25 S the lower part of the bead (171), seen along the axis of flow (X-X), a radius of curvature (RI) will make IT that (R2) of the flow cavity. 14. A gate valve according to one of claims 12 and 13, characterized in that, if ç / designates the angle made with the axis (YY) of the operating rod, the plane tangent to the surface sealing along its mean line (61), said clearance (j) evolves as follows: a Here of the Type j = j | _ sin cL —.b, where a and fc are constants. \ f \ h \) X '\ / V î v> \ · \