The present invention provides a seal gasket which is inserted between the ball valve body and the seat retainer in the cryogenically cooled liquefied natural gas ball valve to prevent the leakage of fluid so that the seal gasket can be cured and contracted under the influence of cryogenic temperature to prevent the fluid from leaking. A seal gasket mechanism.

Natural gas is transported through pipes in a liquefied state at -196℃ for the convenience of storage, and the ball valve used as a means for opening and closing the flow path of liquefied gas is a seat ring mounted to the seat retainer in contact with the ball. And a seal gasket inserted between the valve body and the seat retainer.

The seal gasket mechanism of the retainer for maintaining the airtightness of the conventional ball valve is a non-metal seat ring (6) having a resilient contact with the metal ball (2), as shown in Figure 1, the seat holding the seat ring It comprises a retainer (3), a spring (4) to assist the seat retainer and a guide (5) and a seal gasket (7) inserted between the valve body (1) and the seat retainer to prevent leakage of fluid.

However, since the seal gasket is exposed to extremely low temperatures, it is difficult to prevent fluid leakage since the O-ring of the commonly used type may cause hardening shrinkage to maintain airtightness between the seat retainer and the valve body.

The present invention is designed to maintain the airtightness between the seat retainer and the valve body by changing the shape of the seal gasket and the shape of the seal gasket due to the pressure of the fluid even if the seal gasket is cured by the effect of cryogenic temperature. The gasket is forcibly press-fitted by a nut fastened to the outer diameter side of the seat retainer to provide a configuration in which the seal and the seal come into contact with each other to induce deformation and to be in close contact with the seat retainer and the valve body. It is an object to employ a resin to prevent the fluid from leaking even if it is cured.

Model utility content

The purpose of this utility model is to provide a kind of ultralow temperature fixing ball valve soft seal valve seat.

The utility model provides ultralow temperature fixing ball valve soft seal valve seat to comprise: valve body, valve seat insert, butterfly spring and spring energized seal, valve seat insert is arranged on valve body, butterfly spring and spring energized seal are separately positioned on the diverse location between valve lateral body and valve body, and spring energized seal is made up of chuck and the spring that is positioned at this chuck.

Preferably, valve seat insert takes interference fit to be assigned in the groove of valve body, has the overhead kick that stops valve seat insert to be blown in the groove of valve body.

Preferably, valve body and spherome surface are 45 ° of inclined design.

The material of valve seat insert is preferably PCTFE.

The jacket material of spring energized seal is preferably RPTFE, and the spring material of spring energized seal is preferably Elgiloy.

Accompanying drawing explanation

Fig. 1 is a kind of ultralow temperature fixing ball valve soft seal valve seat of the present utility model;

Fig. 2 is the partial enlarged drawing of the anti-overhead kick structure blowing out of valve seat insert.

In figure: 1-valve body, 2-valve seat insert, 3-butterfly spring, 4-spring energized seal, 5-lateral body, 6-spheroid, 7-overhead kick.

Embodiment

Following design main points have mainly been considered in proposition of the present utility model:

1) under ultra-low temperature surroundings, part is easily out of shape, and extreme environment, to seal request harshness, must strictly be controlled element precision;

2) under ultra-low temperature surroundings, the contraction of each part is inconsistent, control gap, the machining accuracy of control part;

3) under ultra-low temperature surroundings, the choosing and the anti-structural design that blows out of seal ring of valve base sealing loop material;

4) under ultra-low temperature surroundings, the choosing of the valve seat back side and lateral body sealing material;

5), under ultra-low temperature surroundings, provide choosing of valve seat insert prefastening force spring;

6) under ultra-low temperature surroundings, the problem of valve lumen medium pressure release.

For above design main points, work out and can meet the ultralow temperature fixing ball valve soft seal valve seat using under ultralow temperature medium operating mode. A kind of concrete mode of execution is as depicted in figs. 1 and 2:

Comprise: valve body 1, valve seat insert 2, butterfly spring 3 and spring energized seal 4, valve seat insert 2 is arranged on valve body 1, butterfly spring 3 and spring energized seal 4 are separately positioned on the diverse location between lateral body 5 and the valve body 1 of valve, and spring energized seal 4 is made up of chuck and the spring that is positioned at this chuck.Valve seat insert 2 takes interference fit to be assigned in the groove of valve body 1, has the overhead kick 7 that stops valve seat insert 2 to be blown in the groove of valve body 1.Valve body 1 is 45 ° of inclined design with spherome surface 6.

Each part further illustrates as follows:

1. the material selection Austenitic Stainless Steel of valve body 1, under-196 ℃ of cryogenic media operating modes, Austenitic Stainless Steel will carry out deep-cool treatment, reason: the one, if the Martensitic transformation starting point of steel is higher than the serviceability temperature of valve, under serviceability temperature, in steel, part austenite will be transformed into martensite, to cause Volume Changes, cause sealing surface distortion; The 2nd, in the time that valve temperature is down to serviceability temperature, due to shrinkage and action of thermal difference, will cause the irregular distortion of part.

So adopt cryogenic treatment that these two kinds of distortion are eliminated, part deep-cool treatment is general to be repeated twice.

2. the material selection PCTFE(polychlorotrifluoroethylene of valve seat insert 2), PCTFE material is-196℃～150℃ as valve seat insert serviceability temperature scope, PCTFE material has excellent cryogenic property, liquid gas and liquid oxygen, low gas permeability and non-absorbency energy, high tensile and low cold flow characteristic. Be extraordinary sealing material, can meet-196℃ of cryogenic media operating modes completely.

3. valve body 1 back side and lateral body 5 sealings adopt spring energized seal 4, spring energized seal 4 is to be made up of chuck and spring, jacket material is RPTFE(Reinforced Polytetrafluoroethylene),reinforced TFE, spring material is Elgiloy(Elgiloy, or is called Ai Erjiluoyi elgiloy).Temperature using scope of spring energized seal is -196℃～200℃, this kind of spring energized seal is except soluble alkali metal, and high temperature fluorine gas and chlorine trifluoride, react with any chemical reagent hardly.

4. valve seat insert prefastening force spring is provided, adopts butterfly spring 3 to substitute traditional helical spring. Because being installed, helical spring need on valve seat or valve lateral body, bore spring eye, when low temperature fixing ball valve does high-pressure seal experiment at normal temperatures, the easy ponding of spring eye or steam, be not easy the ponding in spring eye or steam to discharge, ponding in worst cold case lower spring hole or steam can freeze rapidly, thereby cause spring failure. And adopt butterfly spring not have ponding or steam ice formation issues, thereby effectively solve the problem of spring failure.

5. the anti-structural design that blows out of valve seat insert 2, realizes and prevents that valve seat insert 2 from being blown out by medium from three aspects. First, valve seat insert 2 use press are pressed in valve body 1 groove, take interference fit that seal ring is tight with in valve seat groove. Secondly, in valve seat groove, design two overhead kick 7(as shown in Figure 2), after seal ring is pressed in valve seat groove, overhead kick 7 can stop valve seat insert 2 to be blown further. Again, valve body 1 is 45 ° of inclined design with spherome surface 6, makes seal ring gap suitable for reading very little, and in the situation that medium pressure is certain, spheroid 6 is in the moment of opening and closing, and the power of blowing acting on valve seat insert 2 can become very little. Guarantee that from above 3 designs valve seat insert 2 can not blown out by medium valve opening and the process of closing.

Working principle is as follows:

When valve is during in complete shut-down position, promote valve body 1 integrated moving by butterfly spring 3, make valve seat insert 2 contact spheroid 6, under the thrust of butterfly spring 3, valve seat insert 2 produces pretension specific pressure with spheroid 6, thereby forms initial sealing. The spring that spring energized seal is 4 li struts chuck, make chuck and lateral body 5 surfaces and valve body 1 surface form seal pressure, in the time passing into medium, before valve, increase gradually with valve body lumen pressure reduction, spring energized seal 4 inner chamber pressure mediums further make inside and outside two sealing lips of chuck be adjacent to more closely valve body 1 and lateral body 5 surfaces, form larger seal pressure. Under the poor effect of pressure medium, make the also more effective spheroid 6 that is adjacent to of valve seat insert 2 simultaneously, form larger seal pressure, to guarantee the sealing between valve body 1 and spheroid 6.Take from pressure-relief type seat design, in the time that valve lumen pressure medium raises extremely, when the design pressure of pressure >=1.33 of valve pocket medium times, middle cavity pressure can be pushed valve seat open, upstream or downstream carry out pressure release, thereby guaranteed the safety of valve lumen.