BE520731A

BE520731A -

Info

Publication number: BE520731A
Authority: BE

Description

       

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  SOUPAPE A JOINT D'ETANCHEITE. 



   Cette invention est relative à des soupapes en général, mais concerne plus particulièrement des soupapes ayant des joints d'étanchéité disposés tout près des extrémités de l'obturateur. 



   Depuis des années, les soupapes sont construites avec différente; dispositions de garniture pour empêcher les fuites, mais de telles dispositions de garniture nécessitent un renouvellement et un réglage fréquents pour empêcher des fuites de fluide. Certaines soupapes, en particulier celles du type lubrifié, ont été construites pour un contact métal contre métal, l'étanchéité étant réalisée par un lubrifiant refoulé sur la surface entre les parties mobiles. Une telle disposition est très satisfaisante excepté lorsqu'une matière étrangère est entrainée dans le lubrifiant et maintient les parties hors de contact.

   En conséquence, un des objets de la présente invention consiste à prévoir une soupape soit du type simple soit du type lubrifié, dans laquelle il est prévu des joints disposés   intérieu-   rement,qui empêchent de façon positive les fuites de se produire aux zones d'obturation du col ou de la base de la soupape. 



   , Un autre objet de l'invention consiste à fournir une soupape lubrifiée ayant un joint de col ou de tige qui se déplace avec l'obturataeur pour permettre un dégagement sûr pour le lubrifiant tout en empêchant une perte de charge de la soupape. 



   Un autre objet encore de l'invention consiste à fournir une soupape ayant des joints disposés intérieurement, qui sont placés tout près de la tige et de la base de l'obturateur et maintenus en position par un seul élastique. 



   Un autre objet encore de l'invention consiste à fournir une soupape ayant une paire de joints espacés maintenus en position par une seule plaque de compensation de pression. 

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   Ces objets de l'invention et d'autres encore apparaîtront clairement aux gens du métier par l'étude de la   description   donnée ci-après et des dessins ci-annexés, dans lesquels :
La figure 1 est une vue en coupe d'une soupape du type lubrifié perfectionné. 



   La figure 2 est une vue à plus grande échelle d'une partie de l'obturateur avant son introduction dans le corps de la soupape. 



   La figure 3 est une vue en coupe à plus grande échelle de la partie supérieure de l'obturateur et du corps de soupape selon la figure 1. 



   La figure 4 est une vue en coupe fragmentaire de la partie inférieure de la soupape de la figure 1, mais illustrant une légère modification de celle-ci. 



   La figure 5 est une vue en coupe similaire à celle de la figure 1, mais montrant une soupape du type non lubrifié. 



   Si l'on se reporte à présent aux dessins en détail, on verra que la soupape est constituée de deux parties principales, à savoir le corps A et l'obturateur B. Le corps A est constitué de parties de fixation 2 au moyen desquelles il peut être relié à une tuyauterie pour la transmission et la commande de l'écoulement de fluide à travers la soupape. Les parties de fixation 2 sont unies par un passage coupé pratiquement à angle droit par un forage ayant une surface usinée 4. Ce forage est ouvert à une extrémité et destiné à être fermé par un obturateur de base 6, de préférence vissé dans le corps comme montré et présentant une cavité 8 pour recevoir un dispositif élastique tel qu'un ressort 10. L'extrémité supérieure du forage est en partie fermée par des épaulements en surplomb 12 dont la surface intérieure est usinée pour fournir un siège 14. 



   L'obturateur B est formé de préférence d'une partie   cylindri-   que 16 destinée à s'adapter étroitement à l'intérieur du forage usiné du corps, et cette partie cylindrique présente un passage 18 destiné à être disposé soit en alignement, soit transversalement par rapport au passage du corps pour commander de ce fait l'écoulement d'un fluide à travers la soupape. Une partie de l'extrémité supérieure de   l'obturateur   est usinée pour donner une surface de siège plane 20 s'étendant vers l'intérieur vers le centre de l'obturateur,   où   elle rejoint un épaulement droit 22 qui peut avoir sa surface extérieure soit verticale,   c'est-à-dire   parallèle à l'axe de l'obturateur, soit légèrement dégagée comme montré clairement aux figures 2 et 3.

   La surface supérieure de l'épaulement à gradin 22 s'étend vers l'intérieur pour venir rejoindre une partie de tige cir-   cualire   agrandie 24 s'étendant vers le haut à travers l'ouverture 26 formée dans la paroi terminale supérieure du corps. La tige s'étend vers le haut au delà de la partie circulaire pour fournir une partie active 28, carrée ou conformée d'une autre fagon, et destinée à recevoir une clef, un dispositif d'engrenages ou un autre moyen pour faire tourner l'obturateur de la soupape dans le corps.L'obturateur tel que représenté sur les figures 1 à 4 inclusivement, est de préférence du type lubrifié et contient du lubrifiant fourni sous pression exercée par un piston 30, et se dirigeant vers le bas   à   travers la tige et vers l'extérieur à travers des passages 32,

   vers des rainures relativement longues 34, diamétralement opposées et qui sont reliées, à leurs extrémités inférieures, à une rainure circonférentielle 36. Des rainures courtes 38, diamétralement opposées, sont disposées sur les côtés opposés des passages 18 par rapport aux rainures 34, et ne sont pas en liaison directe avec les passages 32 ou la rainure circonférentielle 36. Cependant, lorsque la soupape est dans la position entièrement ouverte ou fermée; le lubrifiant peut être amené à ces rainures courtes au moyen de petites rainures ou cavités 40, formées dans le corps comme on l'a clairement représenté.

   Le lubrifiant amené sous pression,par la vis 30 remplira complètement les rainures fromant le système de lubrification de la soupape, et remplira aussi la ca- 

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 vite   42,   formée entre l'épaulement 12 en surplomb et l'extrémité supérieure de   l'obturateur.   



   .Des essais ont montré que pratiquement la moitié de l'effort de rotation de   l'obturateur   dans le corps est due à la charge   terminale,c'est   à-dire exercée par la pression du fluide dans le passage, tendant à expul- ser l'obturateur par l'ouverture 26. Afin de restreindre ce frottement de charge terminale. et de produire, en même temps, une étanchéité efficace, on a pràyu un joint de siège de tête ou de col G.

   Ce joint est représenté clairement en particulier aux figures 2 et   3,¯est  constitué d'une surface ¯ inférieure 44, destinée à reposer.sur la surface usinée 20 de l'obturateur, et est constitué également d'une surface supérieure 40 destinée à s'appuyer contre la surface usinée 14 des épaulements en surplomb   12.   Les surfaces supérieure et inférieure sont séparées d'une distance suffisante, c'est- à-dire que l'épaisseur du joint est choisie de telle manière que la surfa- ce supérieure 46 soit disposée légèrement au-dessus¯ du bord.supérieur de l'épaulement 22. La paroi intérieure 48 s'étend de préférence verticalement et s'adapte étroitement sur l'épaulement ou partie à gradin 22.

   On a découvert après¯des essais répétés que la surface extérieure 50 doit être inclinée comme on l'a représenté, et que le degré d'inclinaison,c'est à-dire l'angle formé entre les surfaces 50 et 44, doit être de l'ordre de 30 à 55, 45  donnant les résultats les plus favorables. Ce joint est de préférence fabriqué en tétrafluoréthylène, composé qui est une substance chimiquement inerte, capable de résister raisonnablement aux températures élevées et ayant un toucher naturellement huileux et de bonnes propriétés d'antifriction. Cette substance, toutefois, étant un plastique, s'écoule sous l'action de la pression et doit être soumise à une pression pratiquement.-constante afin d'assurer une étanchéité convenable.

   Dans la position assemblée normale, le joint aura la forme représentée %la figure 2, mais après assemblage et. application de pression, le joint s'écoulera   en.se   palant de lui-même contre l'épaulement 22 légèrement en   surplomb,et,   en refoulant une petite lèvre 52 dans l'espace situé entre la surface su-   périeure   de l'épaulement 22 et la surface usinée 14 des épaulements en surplomb du corps. Comme défini précédemment., il n'est pas néèessaire que l'épaulement 22 présente un dégagement ou soit en surplomb comme représenté, bien qu'une telle conformation aidera à assurer le déplacement du joint G avec 1'obturateur pendant l'opération de décharge de la soupape, opération qui sera décrite plus loin.

   Le constituant vertical du lubrifiant sous pressïon dans la cavité 42. agissant sur la paroi inclinée 40, maintiendra efficacement   lejoint  G en contact avec l'obturateur pendant le mouvement de descente ou de, décharge de l'obturateur. Une pression élevée dans le corps donnera, naturellement, une charge terminale élevée. tendant à refouler davantage la substance du joint et à augmenter la longueur de la lèvre 52. 



  Cependant, comme celle-ci tend à augmenter, l'espacement entre le bord supérieur de l'épaulement. 22 et l'épaulement 12 diminue, et cet espace diminué conjointement avec la longueur accrue de¯la langue 52¯ stoppera tout refoulement ultérieur et   empêchera   la substance du joint   d'être   chas- sée verticalement vers le haut dans l'espace libre entre le trou 26 et la partie de tige ronde 24. Dans certains cas, il peut être désirable de four-.. nir undsoupape du type.non lubrifié et, en pareils cas, comme il ne faut pas combattre la pression du lubrifiant ni un déplacement axial de l'obturateur, pn peut employer un joint de tête. rectangulaire G1,   pomme, montré   clairement à la figure 5.

   Ce joint de tête rectangulaire aura-sa surface inférieure portant contre la surface supérieure 20 de l'obturateur, et sa surface supérieure portant contre l'épaulement usiné 14 du corps, exactement comme il était décrit en relation avec les figures 1 à 3, et le refoulement ou écoulement wers l'intérieur sera de même controlé par l'épaulement 22 exactement de la même manière que décrit précédemment. - 
Afin.d'empêcher toute fuite de fluide par le joint existant entre le corps et l'obturateur de base, un joint inférieur H peut être employé, comme on a montré clairement aux figures 1 et 5.

   Ce joint inférieur pré- 

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 sente une surface supérieure 60 destinée à s'appuyer sur la surface infé-   rieure   de   l'obturateur   B, et une surface extérioure ou paroi verticale 62 destinée à   s'appuyer     sur   la paroi usinée 4 du forage transversal. la surface inférieure 64 de la   surface   intérieure inclinée 66 sont destinées à s'appuyer contre des surfaces plates et inclinées d'une plaque de pression ou plaque'compensatrice 68. Cette plaque est espacée de l'extrémité inférieure   de,¯l'obturateur   et est soutenue en position en reposant sur l'extrémité supérieure du ressort 10 dont ila été question précédemment. 



  Ainsi,on verra que la ressort 10, qui est normalement placé sous l'influence d'une   précompression   relativement forte pendant l'assemblage de la soupape, sollicitera constamment la plaque de pression 68 vers le haut, et maintenant ainsi à la fois le joint inférieur H et les joints supérieurs G ou G1 sous pression continue et constante,¯¯en assurant ainsi efficacement l'étanchéité¯ de la soupape   contre--toute   fuite de fluide   par, l'une   ou l'autre des parties de col pu de base. Une pression vers la hart constante de la plaque de pression 68 tendra, par 'suite de la surface intérieure,en biais du joint H, à déployer le joint et à le maintenir en prise étroite avec le   forage,4   du, corps.

   Dans le mode de réalisation du type non lubrifié représenté à la figure 5, il n'y aura pas de déplacement axial   impor-   tant de l'obturateur dans le corps. Cependant, en ce qui concerne le mode de réalisation représenté aux figures 1 à 4 inclusivement, il est désirable qu'il survienne un déplacement axial afin qu'il ne puisse se créer des pressions de lubrifiant élevées pouvant entraîner une rupture du corps. 



  Pour certains fluides, il a été trouvé que le-joint de base H peut être supprimé, le   ressort 10   portant alors directement sur le fond de l'obturateur   comme   représenté clairement à la figure 4, mais le déplacement axial de,l'obturateur sera le même, que la plaque de pression et le joint inférieur soient utilisés pu non.

   En supposant que le lubrifiant sous pression soit chassé dans la soupape à une pression élevée, il remplira le système de lubrification comprenant les passages 32, les rainures 34, 36, 38 et la cavité   42.   Dès que le système est,, complètement chargé de lubrifiant , une pression tendra s'élever rapidement dans la chambre   42,   avec pour résultat qu'elle vainc la compression du ressort 10 et la.pression du   fuide   -tendant à expulser l'obturateur du trou 22.

   Dès   que..la   pression dans la chambre 42 a vaincu ces¯.forces, l'obturateur se déplacera vers le bas ou axialement dans le corps, et le lubrifiant peut alors sortir en s'écoulant sur la surface supérieure 46 du joint   G, ç'est  à dire entre cette surface et la surface usinée 14 du corps,   et ,de   là par l'espace entre le trou 26 et la partie de tige circulaire   24.,.Par   suite du calage du joint G contre l'épaulement   22,.

   mais   dû-plus particulièrement au constituant vertical du lubrifiant agissant sur la surface inclinée,¯50, le joint G doit se déplacer vers le bas avec l'obturateur et ne peut tourner ni se déplacer vers le haut en empêchant ainsi l'échappement du lubrifiant en excès, qui est si nécessaire pour empêcher la rupture du corps et la   surlubrification   de la soupape. 



   Bien que l'invention ait été décrite plus ou moins on détail avec référence spécifique aux dessins, il est évident que   l'on   pourra apporter aux parties différentes modifications et arrangements autres que ceux représentés et décrits, pareils arrangements et modifications étant considérés comme entrant dans le cadre des modifications suivantes définis-   sant   l'invention. 

**ATTENTION** fin du champ DESC peut contenir debut de CLMS **.



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  SEALED VALVE.



   This invention relates to valves in general, but more particularly relates to valves having seals disposed close to the ends of the shutter.



   For years the valves have been built with different; packing arrangements to prevent leakage, but such packing arrangements require frequent renewal and adjustment to prevent fluid leakage. Some valves, particularly those of the lubricated type, have been constructed for metal-to-metal contact, sealing being achieved by a lubricant forced onto the surface between the moving parts. Such an arrangement is very satisfactory except when a foreign material is entrained in the lubricant and keeps the parts out of contact.

   Accordingly, one of the objects of the present invention is to provide a valve either of the simple type or of the lubricated type, in which there are provided internally disposed seals which positively prevent leaks from occurring at the areas of. blockage of the neck or base of the valve.



   Another object of the invention is to provide a lubricated valve having a neck or stem seal which moves with the plug to allow safe release for lubricant while preventing pressure drop of the valve.



   Yet another object of the invention is to provide a valve having internally disposed seals which are placed close to the stem and base of the plug and held in position by a single elastic.



   Yet another object of the invention is to provide a valve having a pair of spaced apart seals held in position by a single pressure compensation plate.

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   These objects of the invention and others still will become clear to those skilled in the art by studying the description given below and the accompanying drawings, in which:
Figure 1 is a sectional view of an improved lubricated type valve.



   FIG. 2 is a view on a larger scale of part of the obturator before its introduction into the body of the valve.



   Figure 3 is a sectional view on a larger scale of the upper part of the shutter and the valve body according to Figure 1.



   Figure 4 is a fragmentary sectional view of the lower portion of the valve of Figure 1, but illustrating a slight modification thereof.



   Figure 5 is a sectional view similar to that of Figure 1, but showing a valve of the unlubricated type.



   Referring now to the drawings in detail, it will be seen that the valve consists of two main parts, namely the body A and the shutter B. The body A consists of fastening parts 2 by means of which it may be connected to piping for transmission and control of fluid flow through the valve. The fixing parts 2 are joined by a passage cut almost at right angles by a borehole having a machined surface 4. This borehole is open at one end and intended to be closed by a base plug 6, preferably screwed into the body as shown and having a cavity 8 for receiving a resilient device such as a spring 10. The upper end of the borehole is partly closed by overhanging shoulders 12, the interior surface of which is machined to provide a seat 14.



   The shutter B is preferably formed of a cylindrical part 16 intended to fit closely inside the machined borehole of the body, and this cylindrical part has a passage 18 intended to be disposed either in alignment or transversely. relative to the passage of the body to thereby control the flow of a fluid through the valve. A portion of the upper end of the shutter is machined to provide a planar seating surface 20 extending inwardly toward the center of the shutter, where it meets a straight shoulder 22 which may have its outer surface either. vertical, that is to say parallel to the axis of the shutter, or slightly clear as shown clearly in Figures 2 and 3.

   The upper surface of the stepped shoulder 22 extends inwardly to meet an enlarged circular shank portion 24 extending upwardly through the opening 26 formed in the upper end wall of the body. The rod extends upwardly beyond the circular portion to provide an active portion 28, square or otherwise shaped, and intended to receive a key, a gear device or other means for rotating the shaft. The valve plug in the body. The plug as shown in Figures 1 to 4 inclusive, is preferably of the lubricated type and contains lubricant supplied under pressure exerted by a piston 30, and pointing downwardly through the rod and outwards through passages 32,

   to relatively long grooves 34, diametrically opposed and which are connected, at their lower ends, to a circumferential groove 36. Short grooves 38, diametrically opposed, are disposed on the opposite sides of the passages 18 with respect to the grooves 34, and not are not in direct connection with the passages 32 or the circumferential groove 36. However, when the valve is in the fully open or closed position; lubricant can be supplied to these short grooves by means of small grooves or cavities 40, formed in the body as clearly shown.

   The lubricant supplied under pressure by screw 30 will completely fill the grooves in the valve lubrication system, and will also fill the chamber.

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 quickly 42, formed between the overhanging shoulder 12 and the upper end of the shutter.



   Tests have shown that practically half of the rotational force of the shutter in the body is due to the terminal load, i.e. exerted by the pressure of the fluid in the passage, tending to expel the shutter through the opening 26. In order to restrict this terminal load friction. and to produce, at the same time, an effective seal, a head seat or neck G seal was used.

   This seal is shown clearly in particular in Figures 2 and 3, ¯ consists of a lower surface ¯ 44, intended to rest on the machined surface 20 of the shutter, and also consists of an upper surface 40 intended to rest against the machined surface 14 of the overhanging shoulders 12. The upper and lower surfaces are separated by a sufficient distance, i.e. the thickness of the joint is chosen such that the surface upper 46 is disposed slightly above the upper edge of the shoulder 22. The inner wall 48 preferably extends vertically and fits tightly over the shoulder or step portion 22.

   It has been found after repeated trials that the outer surface 50 should be tilted as shown, and that the degree of tilt, i.e. the angle formed between the surfaces 50 and 44, should be of the order of 30 to 55, 45 giving the most favorable results. This seal is preferably made of tetrafluoroethylene, a compound which is a chemically inert substance capable of reasonably resisting high temperatures and having a naturally oily feel and good anti-friction properties. This substance, however, being a plastic, flows under the action of pressure and must be subjected to a practically constant pressure in order to ensure a proper seal.

   In the normal assembled position, the gasket will have the shape shown in Figure 2, but after assembly and. application of pressure, the seal will flow by landing on its own against the slightly overhanging shoulder 22, and, forcing a small lip 52 into the space between the upper surface of the shoulder 22 and the machined surface 14 of the shoulders overhanging the body. As previously defined, it is not necessary for the shoulder 22 to have a clearance or be overhanging as shown, although such a configuration will help to ensure the movement of the seal G with the shutter during the discharge operation. of the valve, an operation which will be described later.

   The vertical component of the lubricant pressurized in the cavity 42, acting on the inclined wall 40, will effectively maintain the seal G in contact with the shutter during the downward or discharging movement of the shutter. High pressure in the body will naturally give a high terminal load. tending to further push back the substance of the seal and increase the length of the lip 52.



  However, as this tends to increase, the spacing between the upper edge of the shoulder. 22 and the shoulder 12 decreases, and this reduced space together with the increased length of the tongue 52¯ will stop any further backflow and prevent the gasket substance from being forced upwards vertically into the free space between the hole 26 and round shank portion 24. In some cases it may be desirable to provide an unlubricated type valve and, in such cases, as lubricant pressure and axial displacement should not be addressed. shutter, pn can use a head gasket. rectangular G1, apple, shown clearly in Figure 5.

   This rectangular head seal will have its lower surface bearing against the upper surface 20 of the shutter, and its upper surface bearing against the machined shoulder 14 of the body, exactly as described in relation to Figures 1 to 3, and the discharge or flow towards the interior will likewise be controlled by the shoulder 22 in exactly the same manner as described previously. -
In order to prevent any leakage of fluid through the existing seal between the body and the base plug, a lower seal H can be employed, as clearly shown in Figures 1 and 5.

   This lower seal pre-

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 There is an upper surface 60 intended to rest on the lower surface of the shutter B, and an exterior surface or vertical wall 62 intended to rest on the machined wall 4 of the transverse borehole. the lower surface 64 of the inclined interior surface 66 are intended to rest against flat and inclined surfaces of a pressure plate or compensator plate 68. This plate is spaced from the lower end of the shutter and is supported in position by resting on the upper end of the spring 10 referred to above.



  Thus, it will be seen that the spring 10, which is normally placed under the influence of relatively strong precompression during valve assembly, will constantly urge the pressure plate 68 upward, and thus maintain both the seal. lower H and upper seals G or G1 under continuous and constant pressure, ¯¯ thus effectively sealing ¯ the valve against - any leakage of fluid through either of the neck parts or of the based. Constantly upward pressure from pressure plate 68 will tend, as a result of the interior surface, across seal H, to deploy the seal and hold it in close engagement with the bore, 4 of the body.

   In the embodiment of the unlubricated type shown in Fig. 5, there will be no significant axial displacement of the shutter in the body. However, with respect to the embodiment shown in Figures 1 to 4 inclusive, it is desirable that there be axial displacement so that high lubricant pressures cannot be created which may cause rupture of the body.



  For some fluids it has been found that the base seal H can be omitted, the spring 10 then bearing directly on the bottom of the shutter as clearly shown in Figure 4, but the axial displacement of the shutter will be the same whether the pressure plate and the lower seal are used or not.

   Assuming that the pressurized lubricant is forced into the valve at a high pressure, it will fill the lubrication system comprising passages 32, grooves 34, 36, 38 and cavity 42. As soon as the system is fully charged with lubricant, pressure will tend to build rapidly in chamber 42, with the result that it overcomes the compression of the spring 10 and the pressure of the fluid tending to expel the plug from the hole 22.

   As soon as..the pressure in the chamber 42 has overcome these forces, the shutter will move downwards or axially in the body, and the lubricant can then exit by flowing over the upper surface 46 of the seal G, that is to say between this surface and the machined surface 14 of the body, and thence through the space between the hole 26 and the circular shank portion 24. As a result of the wedging of the seal G against the shoulder 22 ,.

   but due-more particularly to the vertical constituent of the lubricant acting on the inclined surface, ¯50, the seal G must move downwards with the shutter and cannot rotate or move upwards, thus preventing the escape of the lubricant in excess, which is so necessary to prevent body rupture and over-lubrication of the valve.



   Although the invention has been described in more or less detail with specific reference to the drawings, it is obvious that various modifications and arrangements other than those shown and described can be made to the parts, such arrangements and modifications being considered to be within the scope of the invention. within the scope of the following modifications defining the invention.

** ATTENTION ** end of DESC field can contain start of CLMS **.

Claims

CLAIMS 1. In a valve, a valve body, a valve plug rotatably mounted in the body, overhanging shoulders formed on the body, an interior seating surface formed on said overhanging shoulders and covering at least a part of it. of one end of the shutter, a seat surface formed on the said end of said shutter, a right shoulder 'also formed on the end in question adjacent to the seat surface, and a seal bearing on said shutter and body seat surfaces, said seal being of sufficient thickness <Desc / Clms Page number 5> health to prevent? ' the contact between said right shoulder and the interior seat surface of said overhanging shoulder of the body.

2. In a valve, a valve body, a valve plug rotatably mounted in the body, overhanging shoulders formed on the body, an interior planar seat surface formed on said overhanging shoulders and covering a surface. part of at least one of the ends of the shutter, a seat surface formed on the end in question of said shutter, a straight shoulder formed also on the end in question adjacent to the seat surface and covered by said flat surface , a first seal closely surrounding said right shoulder and bearing on said shutter and body seat surfaces, and of sufficient thickness to prevent contact between said right shoulder and the inner seat surface of said overhanging shoulder. body,

a second seal bearing on the opposite end of said shutter, and means resiliently urging said first and second seals into contact with the body.

3. In a valve, a valve body or a valve plug rotatably mounted in the body, overhanging shoulders formed on the body, an interior seating surface formed on said overhanging shoulders and covering at least part of it. from one end of the shutter, a seat surface formed on.

the end in question of said shutter, a right shoulder also formed on the end in question adjacent to the seat surface, a first seal closely surrounding said shoulder and bearing on, said seat surfaces of the shutter and of the body, and of sufficient thickness to prevent contact between said right shoulder and the inner seat surface of said overhanging shoulder of the body, a second seal bearing on the opposite end of said shutter, and resiliently urging means, said first and second seals in contact with the body, said means comprising a spring and a. compensating plate bearing directly on said second seal.

4. In a valve, a valve body, a valve plug rotatably mounted, in the body, overhanging shoulders formed on the body, an interior planar seat surface formed on said overhanging shoulders and covering at least a part of one of the ends of the shutter, a seat surface formed on the end in question of said shutter, a straight shoulder formed also on the end in question adjacent to the seat surface and covered by said interior seat surface, anda seal coming in close contact with the sides of said right shoulder and bearing on said shutter and body seat surfaces outwardly of said shoulder,

said seal being of greater thickness than the height of said shoulder to thereby prevent contact between said shoulder and the interior seat surface covering said shoulder of the body.

5. In a valve, a valve body having a substantially cylindrical bore, a valve plug rotatably mounted in the bore of the body., A rod formed on the plug and protruding outwardly through the body, shoulders. overhang formed on the body and surrounding said rod, an interior planar seat surface formed on said overhanging shoulders and covering at least part of one end of the shutter, a seat surface formed on the end in question of said shutter, a protruding shoulder extending outwardly from one of said seat surfaces towards and covered by the other surface adjacent to said rod,

and a seal extending from said seat surfaces and closely engaging the side of said shoulder remote from said rod, said seal having a thickness greater by a predetermined proportion than the height of said protruding shoulder, thereby preventing contact. between said shoulder and the cover surface and to control the flow of said seal to said rod. <Desc / Clms Page number 6>

6. In a valve, a valve body having a substantially cylindrical bore, a valve plug rotatably mounted in the bore of the body, a rod formed on the plug and protruding outwardly through the body, shoulders in. overhang formed on the body and surrounding said rod, an interior seat surface formed on said overhanging shoulders and covering a part of at least one of the ends of the shutter, a seat surface formed on the end in question of said shutter, a protruding shoulder extending outwardly from one of said seat surfaces and adjacent to said rod,

a first seal bearing on said seat surfaces and closely engaging the side of said shoulder remote from the stem, and being of a thickness greater than the height of said shoulder, a second seal bearing on the other end of said remote shutter of the rod and having its sides closely engaging the borehole of said body, a compensating plate spaced from said shutter and bearing on said second seal, and resilient means applying pressure on said compensating plate and said two seals.

7. In a valve, a valve body with a substantially cylindrical bore, a valve plug rotatably mounted in the bore of the body, a rod formed on the plug and protruding outwardly through the body, shoulders overhang formed on the body and surrounding said rod, an interior seat surface formed on said overhanging shoulders and covering at least part of one end of the shutter, a seat surface formed on the subject end of said shutter, a protruding shoulder extending outwardly from one of said seat surfaces and adjacent to said stem a first seal bearing on said seat surfaces and closely engaging therein with the side of said shoulder remote from the stem,

and being of greater thickness than the height of said shoulder, a second seal bearing on the other end of said shutter remote from the rod and having its sides closely engaging the borehole of said body, a compensating plate spaced from said shutter and bearing on said second seal, and resilient means applying pressure to said compensator plate and said two seals, said compensator plate being formed and designed to increase the tightness of engagement between said second seal and the bore of the body . - 8.

In a lubricated valve, a valve body, a valve plug rotatably mounted in the body, overhanging shoulders formed on the body and having an interior seat surface covering a portion at the mpins of one end of the plug , a seat surface formed on the said end of the shutter, a shoulder projecting outwardly from one of said surfaces towards the other surface in overlapping relation, a seal closely engaging a side of said shoulder and bearing on said seat surfaces and forming a lubrication chamber together with said surfaces and the body, means for introducing lubricant under pressure into said lubrication chamber,

and means for resiliently urging said plug in engagement with said seal and said seal in engagement with said interior body seat surface, said means under increasing pressure in said lubrication chamber to allow axial displacement of said plug in said body, whereby the lubricant can escape beyond said seal.

9. The construction of claim 8, characterized in that said shoulder is formed on said shutter and said seal moves axially with said shutter to allow lubricant to escape between said seal and the interior seat surface of the body.

10. The construction of claim 8, characterized in that the side of said seal forming part of the lubrication chamber <Desc / Clms Page number 7> is inclined, whereby the pressure of the lubricant which acts on it will keep the seal in engagement with the seat surface on which the said shoulder projects, during the axial displacements of the shutter.

11. In a lubricated valve, a valve body having a substantially cylindrical bore, a valve plug rotatably mounted in the bore of the body, a rod formed on the plug and protruding outwardly through the body, an overhanging shoulder formed on and surrounding said rod, an interior seat surface formed on said overhanging shoulder and covering the end of the shutter adjacent to said rod, ¯a seat surface formed on the end of the shutter adjacent to the stem, a straight shoulder projecting upwardly from said shutter and between said last-mentioned seat surface and the stem ,, ¯ a seal bearing on said seat surfaces and closely engaging with the side of said shoulder remote from the rod,

of a thickness greater than the height of said shoulder, said seat surfaces, the joint and the bore of the body forming a lubrication chamber surrounding said tge, means for introducing lubricant under pressure into said lubrication chamber, and a means for resiliently urging said shutter in engagement with said seal and said seal ¯ in engagement with said seat surface, interior of the body, said means under increasing pressure in said chamber to allow axial displacement of the body. obturator in the body, whereby the lubricant can escape beyond said seal.

12. The construction of claim 11, characterized in that the side of said seal forming one side of the lubrication chamber is inclined inwardly and upwardly at an angle small enough to ensure axial displacement of the seal together. with said shutter.

13. The construction of claim 11, characterized in that the side of said seal forming one of the sides of the lubrication chamber is inclined towards the inside, and upwards by an angle of between 30 and 60 for, ensuring the axial displacement of the joint together with said obturatour, and also to ensure the engagement of said shoulder by the inner side of the joint.

14. The construction of claim 11 characterized in that said means comprises a second seal bearing on the end of said shutter opposite to the rod, a pressure plate bearing on said second seal and pushing it against the shutter and the borehole. body, and a spring acting resiliently on the center of said pressure plate.

15. As an article of manufacture, a valve gasket which is annular in shape and having a cross section in the shape of a truncated right triangle with the vertical side forming the inner wall of the ring and the inclined side forming the outer wall.

16. As an article of manufacture, a ring-shaped tetrafluoroethylene valve seal having a cross-section in the shape of a truncated right-angled triangle.

17. As an article of manufacture, an annular-shaped tetrafluoroethylene valve gasket having a cross-section in the shape of a truncated right-angled triangle, with the substantially vertical wall forming the inner wall of the ring and the outer wall formed with a inclination forming an angle of between 30 and 60 with respect to the horizontal.