CN217927459U

CN217927459U - Unloading type adjusting steam valve of steam turbine

Info

Publication number: CN217927459U
Application number: CN202222172880.3U
Authority: CN
Inventors: 丁旭东; 王晓斐; 陈可轩; 王勤; 胡枫; 黄肖华; 岳树元; 李琛
Original assignee: Hangzhou Steam Turbine Power Group Co Ltd
Current assignee: Hangzhou Steam Turbine Power Group Co Ltd
Priority date: 2022-08-17
Filing date: 2022-08-17
Publication date: 2022-11-29
Anticipated expiration: 2032-08-17

Abstract

The application provides a steam turbine unloading type adjusting steam valve, which relates to the technical field of steam turbines and comprises a valve casing, wherein the valve casing comprises a valve cavity, and a steam inlet and a steam outlet which are communicated with the valve cavity; the valve disc is arranged in the valve cavity and comprises an unloading flow channel penetrating through the valve disc, one end of the unloading flow channel is communicated with the steam outlet, and the valve disc is used for sealing the steam outlet and opening the steam outlet; the unloading part is arranged in the valve cavity and used for sealing the other end of the unloading flow channel, and the unloading part is arranged to enable the steam inlet to be communicated with the unloading flow channel. The unloading part is firstly utilized to open the unloading flow passage, so that the unloading flow passage communicates the steam inlet with the steam outlet, the steam pressure from the steam inlet pressing the valve disc at the steam outlet is unloaded through the unloading flow passage, the valve disc can be far away from the steam outlet by smaller lifting force to open the steam outlet, and the problems of insufficient lifting force, insufficient strength of valve rod components such as valve rod, increased air leakage and the like in the prior art are avoided.

Description

Unloading type adjusting steam valve of steam turbine

Technical Field

The application relates to the technical field of steam turbines, in particular to a steam turbine unloading type adjusting steam valve.

Background

In the prior art, the main steam admission regulating valve of the conventional steam turbine is designed in a straight-pull mode, and the straight-pull regulating valve is simple in structure and widely used at present. However, when the steam inlet parameters are particularly low and a large-caliber regulating valve is required to be used, the straight-pull regulating valve design may have the situation of excessive lifting force, which causes a series of problems such as insufficient output of a servomotor, insufficient strength of a valve opening component such as a valve rod and increased steam leakage, and thus the safe and efficient operation of the steam turbine is affected.

SUMMERY OF THE UTILITY MODEL

In view of this, the present application provides a steam turbine unloading type steam regulating valve, which aims to solve the above technical problems to a certain extent.

The application provides steam turbine formula of unloading is adjusted the steam valve, steam turbine formula of unloading is adjusted the steam valve and is included:

the valve shell comprises a valve cavity, and a steam inlet and a steam outlet which are communicated with the valve cavity;

the valve disc is arranged in the valve cavity and comprises an unloading flow channel penetrating through the valve disc, one end of the unloading flow channel is communicated with the steam outlet, the valve disc is used for sealing the steam outlet, and the valve disc can move towards the direction far away from the steam outlet so as to open the steam outlet;

and the unloading part is arranged in the valve cavity, is used for sealing the other end of the unloading flow channel, and can move towards the direction far away from the other end of the unloading flow channel so as to enable the steam inlet to be communicated with the unloading flow channel.

Preferably, the steam turbine unloading type regulating steam valve further comprises a limiting member arranged at the other end of the unloading flow channel, the unloading part comprises a first part penetrating through the limiting member and a second part used for sealing the other end of the unloading flow channel,

when the steam inlet is communicated with the unloading flow channel, the second part is also used for being abutted against the limiting component, so that the unloading part is limited.

Preferably, the valve disc comprises a concave part arranged on the end face of the valve disc far away from the steam outlet, the concave part is communicated with the other end of the unloading flow channel, and the limiting member is detachably arranged in the concave part.

Preferably, the valve casing further includes a valve port, the steam turbine unloading type adjusting steam valve further includes a valve cover, the valve cover is arranged on the valve port, a part of the valve cover is arranged in the valve cavity, the part of the valve cover includes a containing cavity, and a part of the valve disc is arranged in the containing cavity.

Preferably, the steam turbine unloading type steam regulating valve further comprises an unloading sleeve, the unloading sleeve is arranged between the inner wall of the containing cavity and the part of the valve disc, and the unloading sleeve is used for unloading steam on the steam inlet side.

Preferably, the steam turbine unloading type regulating steam valve further comprises:

the installation sleeve is provided with one part penetrating through the valve cover and connected with the valve cover, and the other part is arranged in the containing cavity;

a valve rod, one end of which is connected with the relief part, the valve rod penetrates through the mounting sleeve, and the other end of which is exposed to the outside of the valve shell;

the bushing assembly is sleeved on the outer side portion of the valve rod and arranged between the valve rod and the mounting sleeve.

one end of the pull rod is connected with the valve rod;

one end of the lever is hinged with the other end of the pull rod;

the support is connected with the valve shell, and the middle part of the lever is hinged to the support;

and the driving mechanism is hinged with the other end of the lever so as to drive the lever.

the spring holder, set up in the outside of valve gap, the spring holder include the spring and set up respectively in two connecting pieces at the both ends of spring, be close to in two connecting pieces the connecting piece that is close to the valve gap is set up to can along the flexible direction motion of spring, be close to the valve gap the connecting piece with the valve rod is connected, the spring is set up to compression state.

a thermal insulation member connected with the valve rod, the thermal insulation member being disposed between the connecting member near the valve cover and the valve cover;

an adjustment member connected with the valve stem, the adjustment member being disposed between the connection member near the bonnet and the bonnet, a thickness of the adjustment member being configured to be adjustable.

Preferably, the valve gap includes that the steam leakage draws forth the hole, the steam leakage draws forth hole and external environment intercommunication, the bush subassembly includes the steam leakage bush, the installation sleeve include with the through-hole that the position of steam leakage bush corresponds, the steam leakage via the steam leakage bush the through-hole and the steam leakage draws forth the hole and is drawn forth to external environment.

According to the steam turbine formula of unloading regulation steam valve that provides in this application, when the steam outlet is opened to needs, can utilize the off-load portion to open the off-load runner earlier, make the off-load runner with steam inlet and steam outlet intercommunication, make and exert on the valve disc, press the valve disc at the steam outlet the steam pressure that comes from the steam inlet via the off-load runner off-load, this makes and to make the valve disc keep away from the steam outlet with less lifting force in order to open the steam outlet, the lifting force is not enough among the prior art has been avoided, the appearance of the valve member such as valve rod intensity is not enough and the gas leakage increase scheduling problem of opening, thereby can ensure the safe high-efficient operation of steam turbine.

In order to make the aforementioned objects, features and advantages of the present application comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

FIG. 1 illustrates a schematic diagram of a steam turbine dump trim steam valve provided in accordance with an embodiment of the present application;

fig. 2 shows a schematic view of a part of the structure of fig. 1.

Reference numerals:

1-a valve seat; 2-valve disc; 3-an unloading sleeve; 4-a limit nut; 5, installing a sleeve; 6-a valve stem; 7-valve cover; 8-valve casing; 9-a stud; 10-a heat insulation plate; 11-adjusting the washer; 12-a spring seat; 13-a spring; 14-a pull rod; 15-tie-rod joint; 16-knuckle bearing; 17-a lever; 18-oil engine; 19-a scaffold; 20-a relief bushing; 21-a clearance bushing; 22-a flexible graphite sealing ring; 23-steam leakage liner; 24-a compression nut; 25-an unloading section; 26-unloading flow channel; t-leakage outlet hole.

Detailed Description

The technical solutions of the present application will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and operate, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present application, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

In addition, technical solutions between the embodiments may be combined with each other, but must be based on the realization of the technical solutions by a person skilled in the art, and when the technical solutions are contradictory to each other or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope claimed in the present application.

According to the embodiment of the application, the steam turbine unloading type regulating steam valve comprises a valve seat 1, a valve disc 2, an unloading sleeve 3, a limit nut 4, a mounting sleeve 5, a valve rod 6, a valve cover 7, a valve shell 8, a stud 9, a heat insulation plate 10, an adjusting washer 11, a spring seat 12, a spring 13, a pull rod 14, a pull rod joint 15, a joint bearing 16, a lever 17, an oil-operated machine 18, a support 19, an unloading bush 20, a gap bush 21, a flexible graphite sealing ring 22, a steam leakage bush 23, a gland nut 24, an unloading part 25 and an unloading flow channel 26, and the structure and the working principle of the steam turbine unloading type regulating steam valve are specifically described below with reference to fig. 1 and 2.

In an embodiment, the valve housing 8 comprises a valve cavity and a steam inlet and a steam outlet communicating with the valve cavity; the valve disc 2 is arranged in the valve cavity, the valve disc 2 comprises an unloading flow channel penetrating through the valve disc 2, one end of the unloading flow channel is communicated with the steam outlet, the valve disc 2 is used for sealing the steam outlet, and the valve disc 2 can move towards the direction far away from the steam outlet so as to open the steam outlet; the unloading part 25 is arranged in the valve cavity, the unloading part 25 is used for sealing the other end of the unloading flow channel, and the unloading part 25 is arranged to be capable of moving towards the direction far away from the other end of the unloading flow channel so as to enable the steam inlet to be communicated with the unloading flow channel. Therefore, when the steam outlet needs to be opened, the unloading part 25 can be used for opening the unloading flow channel 26, so that the unloading flow channel 26 communicates the steam inlet with the steam outlet, the steam pressure from the steam inlet, which presses the valve disc 2 on the steam outlet, is unloaded via the unloading flow channel 26, and thus the valve disc 2 can be kept away from the steam outlet by using smaller lifting force to open the steam outlet, thereby avoiding the problems of insufficient lifting force, insufficient strength of a valve opening component such as the valve rod 6, increased air leakage and the like in the prior art, and further ensuring safe and efficient operation of the steam turbine. Therefore, the embodiment of the application substantially provides the unloading type regulating steam valve for low-parameter and large-caliber conditions.

As shown in fig. 1, in an implementation, axes of both the steam inlet and the steam outlet may be vertical, and as an example, a moving direction of the valve disc 2 and the relief portion 25 may be an extending direction of the axis of the steam outlet, and further, the valve seat 1 may be provided at the steam outlet, which is in abutting engagement with the valve disc 2 to achieve sealing of the steam outlet.

In an embodiment, the steam turbine unloading type steam regulating valve may further include a limiting member, which may be disposed at the other end of the unloading flow passage, referring to fig. 2, in an embodiment, the limiting member may be a limiting nut 4, and the unloading portion 25 may include a second portion penetrating a first portion of the limiting member and sealing the other end of the unloading flow passage, that is, the unloading portion 25 may be in a stepped shaft shape, a first portion of which has a small diameter and a second portion of which has a large diameter, so that the small diameter portion penetrates the limiting nut 4, and the large diameter portion is used to abut against the limiting nut 4 to limit the unloading portion 25 when the unloading portion 25 is pulled, that is, the large diameter portion is also used to abut against the limiting member when the steam inlet is communicated with the unloading flow passage, so that the unloading portion 25 is limited.

Still referring to fig. 2, in an embodiment, the valve disc 2 may include a recess provided at an end surface (i.e., an upper end surface shown in fig. 1 and 2) of the valve disc 2 far from the steam outlet, the recess may communicate with the other end of the unloading flow passage, a limit nut 4 may be detachably provided in the recess, as an example, an outer portion of the limit nut 4 may be formed with an external thread, an inner portion of the recess may be formed with an internal thread, the limit nut 4 may be screwed into the recess via the cooperation of the external thread and the internal thread, and further, as an example, the limit nut 4 may be formed with an air hole penetrating the limit nut 4 in an axial direction of the limit nut 4, i.e., a vertical direction in the drawing, the air hole being used to communicate the unloading flow passage with a space above the unloading flow passage.

Referring to fig. 1, in an embodiment, the valve housing 8 may further include a valve port, the steam turbine unloading type steam regulating valve may further include a valve cover 7, the valve cover 7 may be disposed to cover the valve port, a portion of the valve cover 7 may be disposed in the valve cavity, the portion of the valve cover 7 may include a receiving cavity, and a portion of the valve disc 2 may be disposed in the receiving cavity. Specifically, valve gap 7 can be the shaft of ladder form on the whole, and the valve port is sealed to the upper portion of the shaft-like valve gap 7 of ladder, and cylindric lower part stretches into in the middle of the valve pocket, and for example cylindric appearance chamber has been seted up from lower terminal surface to lower part, and valve disc 2 also can have cylindric appearance, and this makes the motion of valve disc 2 can be guided by valve gap 7.

Further, the steam turbine unloading type steam regulating valve may further include an unloading sleeve 3, the unloading sleeve 3 may be disposed between the inner wall of the cavity and the portion of the valve disc 2, and the unloading sleeve 3 may be configured to unload steam at the steam inlet side, that is, the unloading sleeve 3 is sleeved at the outer side portion of the valve disc 2, as an example, preferably, the unloading sleeve 3 is provided with a plurality of unloading grooves (where, a sleeve having the unloading grooves and an unloading bush 20 below, a known unloading manner is adopted, which is not described herein again), so as to perform a multistage pressure reduction function, if the unloading flow passage is opened, the steam after pressure reduction may enter the unloading flow passage via the upper portion of the cavity and then flow to the steam outlet, so as to achieve unloading.

Further, still referring to fig. 1, in an embodiment, a portion of the mounting sleeve 5 may extend through the bonnet 7 and connect with the bonnet 7, and another portion of the mounting sleeve 5 may be disposed in the cavity, where the mounting sleeve 5 may also be stepped shaft shaped, with an upper portion extending through the bonnet 7 and a lower portion having a larger diameter and disposed in the cavity. Further, one end, i.e., the lower end, of the valve rod 6 may be connected to the unloading portion 25, the valve rod 6 may penetrate through the mounting sleeve 5, and the other end of the valve rod 6 is exposed to the outside of the valve housing 8, so that the unloading portion 25 may be lifted by the valve rod 6 penetrating through the mounting sleeve 5 and the bonnet 7, and the upper portion of the mounting sleeve 5 may have an external thread, so that the mounting sleeve 5 may be coupled to the bonnet 7 by screwing the gland nut 24 into abutment with the upper end surface of the bonnet 7. In an embodiment, a bushing assembly may be provided at an outer side portion of the valve stem 6, and the bushing assembly may be provided between the valve stem 6 and the mounting sleeve 5, where the bushing assembly provides relief, lubrication, and leakage guide functions for the valve stem 6, which will be described in detail later in the description.

In an embodiment, as shown in fig. 1, one end of the pull rod 14 may be connected to the valve rod 6, one end of the lever 17 may be hinged to the other end of the pull rod 14, for example, the pull rod joint 15 of the pull rod 14 is hinged through the joint bearing 16, the bracket 19 may be connected to the valve housing 8, the middle portion of the lever 17 is hinged to the bracket 19, and the hinged position of the middle portion of the lever 17 to the bracket 19 is the fulcrum of the lever 17; the driving mechanism may be, for example, a servomotor 18, and the driving mechanism is hinged to the other end of the lever 17 to drive the lever 17, which facilitates amplification of the driving force of the servomotor 18 by the lever 17.

In an embodiment, the spring seat 12 may be disposed outside the valve cap 7, and the spring seat 12 includes a spring 13 and two connecting members, for example, two plates, respectively disposed at both ends of the spring 13, and a plate adjacent to the valve cap 7, that is, a lower plate, may be connected to the valve rod 6 so that the spring 13 is set in a compressed state, among the two plates, is disposed to be movable in a telescopic direction of the spring 13. As an example, the upper end face of the bonnet 7 may be provided with two studs 9, the upper plate is fixed to the two studs 9, the lower plate is movable, and the spring 13 continuously applies force to the lower plate since the spring 13 is set in a compressed state.

Further, still referring to fig. 1, the heat insulating member may be, for example, a heat insulating plate 10, may be connected to the valve stem 6, and the heat insulating plate 10 may be disposed between the lower plate and the valve cap 7; the adjusting member may be, for example, an adjusting shim, which may be connected to the valve rod 6, and the adjusting shim may be disposed between the connecting member near the valve cover 7 and the valve cover 7, and the thickness of the adjusting shim may be adjustable, for example, the number of shims may be increased or decreased to adjust the compression amount of the spring 13, thereby adjusting the elastic force applied by the spring 13 to the lower plate, the heat shield plate 10, and the adjusting shim.

Furthermore, in an embodiment, the valve cover 7 may comprise a leakage steam lead-out hole T, which may be horizontal and in communication with the external environment, the bushing assembly comprises a leakage steam bushing 23, the mounting sleeve 5 comprises a through hole corresponding to the position of the leakage steam bushing 23, and the leakage steam is led out to the external environment via the leakage steam bushing 23, the through hole and the leakage steam lead-out hole T. Further, the liner assembly may further include a flexible graphite sealing ring 22 disposed below the steam leakage liner 23, a clearance liner 21 (e.g., a large clearance liner) disposed below the flexible graphite sealing ring 22, and a relief liner 20 (i.e., a liner with relief slots) disposed below the clearance liner 21.

On the basis of the above description, the steam turbine unloading type regulating steam valve will be further described below, in an embodiment, the valve casing 8 of the steam turbine unloading type regulating steam valve is independent, the upper end of the valve casing 8 is sealed by the valve cover 7, the integrated valve cover 7 extends into the inside of the valve casing 8, and the sealing also provides support and protection for each internal part. The mounting sleeve 5 is fixed inside the bonnet 7 by a compression nut 24 through the bonnet 7 for mounting the seal of the valve stem 6 and providing a guide for the valve disc 2. The valve rod 6 penetrates through the mounting sleeve 5, one end of the valve rod is connected with the valve core part, and the other end of the valve rod is connected with a series of transmission mechanisms such as a spring 13.

The valve core part comprises a valve disc 2 and a limiting nut 4, the valve disc 2 is matched with the valve seat 1 to form a main steam flow channel, and the unloading part 25 on the lower end surface of the valve rod 6 is matched with the unloading flow channel of the valve disc 2 to form a relatively small pressure unloading valve. When the steam valve is adjusted to be closed, steam force acts on the closing direction of the valve, the unloading part 25 and the valve disc 2 are tightly pressed on the valve seat 1 under the action of the steam force and the spring force, and a passage for new steam to enter the through-flow part of the steam turbine is cut off, so that the safety of equipment is ensured.

In order to control the movement of valve disc 2 by the control unit, so as to control the steam flow, a transmission mechanism is connected to valve rod 6, and is hinged with one end of lever 17 through a series of components such as pull rod 14 and knuckle bearing 16. The other end of the lever 17 is hinged to the servomotor 18, and the middle part is connected to a bracket 19 fixed to the valve housing 8. The upper part of the valve stem 6 supports a spring seat 12 by means of a stud 9, thereby holding a spring 13 to overcome the steam force on the valve stem 6 while providing sufficient closing force for the valve. And a heat insulation plate 10, an adjusting washer 11 and other parts are arranged between the spring 13 and the valve cover 7 so as to ensure the safe and stable operation of the valve. An unloading bush 20 with an unloading groove, a large-gap bush, a flexible graphite sealing ring 22, a steam leakage bush 23, a compression nut 24 and the like are sequentially arranged between the valve rod 6 and the sleeve from bottom to top so as to reduce the steam leakage of the valve rod 6. The valve cover 7 is provided with a steam leakage leading-out hole T, and a small amount of steam passing through the flexible graphite sealing ring 22 passes through the steam leakage lining 23 and is led to a proper position through the steam leakage leading-out hole T.

When the steam valve is adjusted to be opened, the valve rod 6 firstly drives the unloading part 25, the unloading part 25 is usually very small in diameter, and the requirement on lifting force for straight-pull opening is not high. An unloading sleeve 3 provided with a plurality of unloading grooves is arranged between the valve disc 2 and the valve cover 7, when steam flows through a gap between the valve disc 2 and the unloading sleeve 3, the unloading grooves play a role of multi-stage pressure reduction, and the decompressed steam reaches a cavity above the valve disc 2 (namely the upper part of a containing cavity), then reaches a cavity behind the valve through an unloading runner and further reaches a steam outlet. According to the regulating steam valve provided by the embodiment of the application, the smooth degree of flowing of each section after the unloading part 25 is opened can be adjusted by adjusting and matching the gap area of each section, the number and the size of the unloading grooves, the size of the unloading part 25 and the like, the pressure of the upper cavity and the pressure of the lower cavity of the valve disc 2 can quickly tend to be balanced, or the upper cavity is only reserved with a very small steam force. The lift of the unloading part 25 can be 5-6 mm, the valve diameter is small, and the flow of the passing steam is very limited.

When the unloading part 25 is fully opened, the valve rod 6 is continuously lifted upwards to drive the limit nut 4 and the valve disc 2, at the moment, the valve disc 2 is opened, and steam reaches a rear cavity of the valve through a flow channel between the valve disc 2 and the valve seat 1 and further reaches a steam outlet. The valve disc 2 has a larger drift diameter and is a main flow passage of steam, and the main flow passage of the steam can be realized by controlling the valve disc 2 through instructions of a control unit electrically connected with the servomotor 18, so that the controlled parameters of the unit meet the operation requirements. The pressure balance makes the lifting force needed by the valve disc 2 greatly reduced, even if a large-caliber adjusting steam valve is selected according to the parameter requirement, the lifting force can be controlled within a reasonable design range, and the safe and stable operation of the whole set of valve is facilitated.

When the steam valve is adjusted to be closed, steam force acts on the closing direction of the valve, the unloading part 25 and the valve disc 2 are tightly pressed on the valve seat 1 under the action of the steam force and the spring 13, and the passage of new steam entering the through-flow part of the steam turbine is cut off.

The above description is only a preferred embodiment of the present application, and not intended to limit the scope of the present application, and all changes that can be made in the details of the present application and the equivalents thereof, or directly or indirectly applied to other related technical fields, without departing from the spirit of the present application are intended to be embraced therein.

Claims

1. A steam turbine dump trim steam valve, said steam turbine dump trim steam valve comprising:

2. The steam turbine dump trim valve of claim 1,

the unloading type regulating steam valve of the steam turbine further comprises a limiting component, the limiting component is arranged at the other end of the unloading flow channel, the unloading part comprises a first part penetrating through the limiting component and a second part used for sealing the other end of the unloading flow channel,

3. The steam turbine dump trim steam valve as recited in claim 2, wherein the valve disc includes a recess disposed in an end surface of the valve disc distal from the steam outlet, the recess communicating with the other end of the dump runner, the stop member being removably disposed in the recess.

4. The turbine dump trim steam valve of claim 1,

the valve casing also comprises a valve port, the steam turbine unloading type steam regulating valve also comprises a valve cover, the valve cover is arranged on the valve port, part of the valve cover is arranged in the valve cavity,

the portion of the valve cover includes a cavity, and a portion of the valve disc is disposed within the cavity.

5. The turbine dump trim steam valve of claim 4,

the unloading type steam regulating valve of the steam turbine further comprises an unloading sleeve, the unloading sleeve is arranged between the inner wall of the containing cavity and the part of the valve disc, and the unloading sleeve is used for unloading steam on the steam inlet side.

6. The steam turbine dump trim steam valve of claim 4, further comprising:

7. The steam turbine dump trim steam valve of claim 6, further comprising:

one end of the pull rod is connected with the valve rod;

one end of the lever is hinged with the other end of the pull rod;

the bracket is connected with the valve shell, and the middle part of the lever is hinged to the bracket;

and the driving mechanism is hinged with the other end of the lever to drive the lever.

8. The turbine dump trim steam valve as in claim 7, further comprising:

9. The steam turbine dump trim steam valve of claim 8, further comprising:

10. The steam turbine dump trim steam valve as in claim 6, wherein the valve cover comprises a bleed outlet aperture in communication with an external environment, the bushing assembly comprises a bleed bushing, the mounting sleeve comprises a through hole corresponding in position to the bleed bushing, and bleed is drawn to the external environment via the bleed bushing, the through hole, and the bleed outlet aperture.