CN203248793U

CN203248793U - Pressure reducing valve

Info

Publication number: CN203248793U
Application number: CN 201320240601
Authority: CN
Inventors: 瞿辉; 吴会福
Original assignee: YANGZHOU VALVES FACTORY CO Ltd
Current assignee: YANGZHOU VALVES FACTORY CO Ltd
Priority date: 2013-05-03
Filing date: 2013-05-03
Publication date: 2013-10-23
Anticipated expiration: 2023-05-03

Abstract

The utility model relates to a pressure reducing valve and belongs to the technical field of pressure piping fittings. The pressure reducing valve comprises a valve body, a valve core, a valve cover, a piston and a connecting pipeline, wherein the valve core and the valve cover are located inside the valve body, the piston is connected with the valve core, the cross section of the piston is larger than the cross section of the valve core, the inner cavity of the valve body is divided into an upper sealing cavity and a lower sealing cavity by the piston and the valve core, and a bypass connecting pipeline is connected with the upper sealing cavity and an outlet of the pressure reducing valve. According to the pressure reducing valve, when media enter the lower cavity of the valve through an inlet of the pressure reducing valve, upward pressure is applied to the valve core to drive the piston to be opened upwards, and then the media flow into a downstream pipeline through the outlet and flow into the upper sealing cavity of the valve body through the connecting pipeline at the same time; due to the fact that the cross section of the upper cavity is larger than the cross section of the lower cavity, when the pressure on the piston is larger than the pressure on the valve core, the valve core is closed downwards together with the piston under the pressure, and then the flow area of the media is reduced, pressure loss occurs to the media, and downstream pressure is reduced. Therefore, the service life of a pneumatic film pressure reducing control valve is greatly prolonged.

Description

Reduction valve

Technical field

The utility model belongs to pressure piping attachment technique field, relates in particular to a kind of reduction valve.

Background technique

Super (super-) critical unit soot blowing system pressure-reducing station of thermal power station special pneumatic film decompression modulating valve, because the abominable (erosion of applying working condition, cavitation phenomenon is serious), large (front 593 ℃ of valve, 28MPa of pressure reduction before and after the valve, 350 ℃, 3.0MPa behind the valve), the internals of valve are shorter working life, bring very big puzzlement for blowing pipe road system of power plant.And owing to temperature, overpressure, this valve manufacture difficulty is quite huge, now domestic this operating mode still dependence on import of the air bladder decompression valve overwhelming majority.

The model utility content

For above-mentioned technical problem, the purpose of this utility model is to provide a kind of reduction valve in the pipeline before the air bladder decompression valve that is installed in, make this pipeline become two-stage decompression, thereby reduced the applying working condition of air bladder decompression valve, made this regulating working conditions valve production domesticization become possibility.

For solving the problems of the technologies described above, the technical solution adopted in the utility model is, a kind of reduction valve comprises valve body, is positioned at spool and the valve gap of valve body, and piston and connecting tube, and described piston is connected in spool, and its cross section is greater than the cross section of spool; Described piston and spool are separated into upper and lower Seal cage with body cavity, and described bypass connecting tube connects described upper Seal cage and reduction valve outlet.

When medium enters the valve cavity of resorption by the import of the utility model reduction valve, spool is upwards opened by the related piston of upward pressure, medium flows into pipeline behind the valve via outlet, medium flows into Seal cage on the valve body through connecting tube simultaneously, because the cross section of piston is greater than the cross section of spool, cause the cross section of epicoele greater than the cross section of cavity of resorption, when the pressure on the piston during greater than the pressure on the spool, the related spool pressurized of piston is closed downwards, this moment, the medium runner area reduced, medium produces the pressure loss, downstream pressure reduces, reach to improve and be installed in after the reduction valve operating mode of air bladder decompression valve in the pipeline, thereby realize greatly improving the air bladder decompression valve beneficial effect in working life.

Further improve as the utility model, described reduction valve comprises modulating valve, and described modulating valve is connected in the described connecting tube, makes on the valve body pressure in the Seal cage controlled by the regulating and controlling valve.

Description of drawings

Fig. 1 is the cross-sectional view of the utility model reduction valve;

MEDIA FLOW was to schematic diagram when Fig. 2 was the work of the utility model reduction valve.

Embodiment

Below in conjunction with accompanying drawing the utility model is made and to be further specified.

As shown in Figure 1, the utility model reduction valve comprises valve body 1, spool 2, piston 3, valve gap 4 and bypass connecting tube 6, and piston and spool body cavity is separated into upper and lower two Seal cages independently, and the cross section of described piston are greater than the cross sections of spool.Valve body 1 is open die forgings, and material is ASTM A182 F91(F92), guarantee to weld with material with pipeline; Spool 2 and piston 3 are selected the precipitation hardening nickel-base alloy ASTM B637 inconel 718 of high temperature, this material has higher tensile strength, fatigue strength, creep strength and good oxidative stability under 700 ℃, and this material has outstanding wear-resisting, erosive wear resistance.Spool is multistage attenuation type adjustment type spool, can effectively regulate piping flow, loine pressure behind the reduction valve.Valve gap adopts the self-tightening sealing structure, and sealability is reliable, as preferably, adopts seal ring 5,8 on the outer peripheral surface of spool and piston, guarantees the valve pocket upper-lower seal, seal ring material ASTM A182 F316L.

The bypass connecting tube connects Seal cage and reduction valve outlet on the valve body, medium behind the valve can be imported Seal cage on the valve body, as preferably, is in series with modulating valve 7 in the connecting tube, and the pressure of Seal cage is to the needs state on the adjustable valve body.

As shown in Figure 2, when medium enters the valve cavity of resorption by the reduction valve low side, spool is upwards opened by the related piston of upward pressure, pressure is P1(28MPa), medium flows into pipeline behind the valve via the high-end outlet of reduction valve, medium this moment modulating valve in bypass flows into Seal cage on the reduction valve, because the cross section of piston is greater than the cross section of spool, when P2 increases to a certain degree namely when medium downward pressure in piston place upwards pressure greater than spool place medium, the related spool pressurized of piston is closed downwards, this moment, spool place medium runner area reduced, medium produces the pressure loss, downstream pressure reduces, continue to regulate bypass valve until behind the valve pipeline pressure be stabilized in P3(18MPa), the air bladder decompression valve that as secondary regulate behind the pipeline this moment can play best regulating action.

Calculated data:

P1=28MPa, A2(piston compression area)=2.5A1(spool compression area)

The medium directed force F 2=P2 * downward directed force F 1=P1 of the A2 medium * A2 that makes progress

As F2＞F1, the related spool of piston is past to be pressed down, i.e. P2 * A2＞P1 * A1

P2＞P1×A1/A2=28/2.5=11.2MPa

Show that the piston cross section is 2.5 times of spool cross section, when namely the epicoele cross section was 2.5 times of cavity of resorption cross section, as long as sealed cavity pressure is not less than 11.2MPa, medium can make the related spool of piston close downwards.

Above embodiment's description is comparatively concrete, detailed; but can not therefore be interpreted as the restriction to this patent scope; should be noted that; for the person of ordinary skill of the art; without departing from the concept of the premise utility; can also make some distortion and improvement, these all belong to protection domain of the present utility model.

Claims

1. reduction valve comprises valve body, is positioned at spool and the valve gap of valve body, and it is characterized in that: described reduction valve comprises piston and bypass connecting tube, and described piston is connected in spool, and its cross section is greater than the cross section of spool; Described piston and spool are separated into upper and lower Seal cage with body cavity, and described bypass connecting tube connects described upper Seal cage and reduction valve outlet.

2. described reduction valve according to claim 1, it is characterized in that: comprise modulating valve, described modulating valve is connected in the described bypass connecting tube.

3. described reduction valve according to claim 1 and 2, it is characterized in that: described piston cross section is 2.5 times of spool cross section.

4. described reduction valve according to claim 3 is characterized in that: be equipped with seal ring on the outer peripheral surface of described piston and spool.