A kind of valve double sealing structure
Technical field
This utility model belongs to valve technology field, particularly relates to a kind of valve double sealing structure, can be used for the lumens such as gate valve, stop valve, check-valves, three-way valve, water pressure test valve and adopts the valve of self sealss pattern.
Background technology
At present, the self sealing structure that High Temperature High Pressure self sealss pattern valve is conventional is be arranged on pendant collet in valve body, grommet, wedge shape sealing ring, gland and support composition, as shown in Figure 1, its operation principle is, wedge shape sealing ring is placed between floating valve gap and the inwall of valve body, utilizes pretension bolt that the pretightning force of floating valve gap is formed initial than pressure.When medium is by valve, under the effect of pressure medium, floating valve gap presses up contracting wedge shape sealing ring, thus reaching the effect of self-tightening sealing.When the pressure medium in valve changes from low to high, to remain that sealing state need to meet two conditions: one is to pass through pretension bolt floating valve gap produces certain initial ratio pressure, and two is when high pressure, and wedge shape sealing ring is not by high pressure conquassation;When the pressure medium in valve from low to high, repeatedly change from high to low time, the sealing surface of wedge shape sealing ring, grommet and pendant collet be vulnerable to impact, it is easy to produce leak outside, shorten the service life of valve.
Summary of the invention
This utility model purpose is for solving in the process repeatedly changed from low to high, from high to low at pressure medium, the problem that the sealing surface of wedge shape sealing ring, grommet and pendant collet is produced impact repeatedly and produces to expose by medium proposes a kind of valve double sealing structure, it is therefore prevented that the generation of valve leakage out of steam system phenomenon.
This utility model is adopted the technical scheme that by solving the problems referred to above:
A kind of valve double sealing structure, the valve body of valve rod it is provided with including inside, the floating valve gap concentric with valve rod it is sequentially provided with from bottom to top in valve body, gland, gland is fixed with valve rack, multiple pretension bolt it is provided with between gland and floating valve gap, described pretension bolt runs through gland and is connected with gland slip, the threaded upper ends of described pretension bolt is connected to nut, threaded with floating valve gap in the lower end of pretension bolt, described gland and valve rack are formed in one, described gland is bolted on valve body, it it is round ring boss bottom described gland, the contact surface place of the medial surface of described round ring boss and floating valve gap is provided with inner seal ring, the contact surface place of the lateral surface of described round ring boss and valve body is provided with exterior seal ring.
Further, described inner seal ring and exterior seal ring all adopt expanded graphite.
This utility model is had the beneficial effect that not destroy on the basis of former sealing effectiveness, gland and support is set to one-body molded body and adds sealing;Inner seal ring and the exterior seal ring of expanded graphite meterial are set between gland and floating valve gap, gland and valve body; original sealing basis is provided with dual-seal function; when original seal produce minor leakage time, because having the protection of inner seal ring and exterior seal ring and preventing the generation of valve leakage out of steam system phenomenon.
Accompanying drawing explanation
Fig. 1 is existing valve sealing structure schematic diagram;
Fig. 2 is structural representation of the present utility model.
Detailed description of the invention
Below in conjunction with accompanying drawing, this utility model is further described.
As shown in Figure 1, valve rod 10 self sealing structure of existing self sealss pattern valve is positioned within valve body 9, the floating valve gap 1 concentric with valve rod 10 it is sequentially provided with from bottom to top in valve body 9, gland 5, gland 5 is fixed with valve rack 3, wedge shape sealing ring 8 it is sequentially provided with from bottom to top between floating valve gap 1 and gland 5, grommet 7, pendant collet 6, multiple pretension bolt 4 it is provided with between gland 5 and floating valve gap 1, described pretension bolt 4 runs through gland 5 and is slidably connected with gland 5, the threaded upper ends of described pretension bolt 4 is connected to nut, threaded with floating valve gap 1 in the lower end of pretension bolt 4, rotating nut makes pretension bolt 4 drive floating valve gap 1 upwards to compress wedge shape sealing ring 8 to form initially ratio pressure.Its operation principle is, when medium is by valve, under the effect of pressure medium, floating valve gap 1 upwards compresses wedge shape sealing ring 8, thus reaching the effect of self-tightening sealing.
As shown in Figure 2, this utility model includes valve body 9, floating valve gap 1, gland 5 and valve rack 3, in order to there is gland 5 described in better seal effect and valve rack 3 is formed in one body, described gland 5 is fixed on valve body 9 by bolt 2, the mid portion of described floating valve gap 1 is through gland 5 and is slidably connected with gland 5, it is round ring boss 14 bottom described gland 5, the medial surface of described round ring boss 14 and the contact surface place of floating valve gap 1 are provided with inner seal ring 12, the lateral surface of described round ring boss 14 and the contact surface place of valve body 9 are provided with exterior seal ring 13, described inner seal ring 12 and exterior seal ring 13 all adopt expanded graphite meterial to make.
In order to facilitate taking-up and the installation of the pendant collet 6 of sealing mechanism, the upper surface of pendant collet 6 is provided with toroidal cavity 11.
This utility model is not destroying on the basis of former sealing effectiveness, gland 5 and valve rack 3 is set to one-body molded body and adds sealing;Inner seal ring 12 and the exterior seal ring 13 of expanded graphite meterial are set between gland 5 and floating valve gap 1, gland 5 and valve body 9; original sealing basis is provided with dual-seal function; when original seal produce minor leakage time, because having the protection of inner seal ring 12 and exterior seal ring 13 and preventing the generation of valve leakage out of steam system phenomenon.