DE102007035431B4 - Control valve especially for fluids with Abströmmöglichkeit for large mass flows - Google Patents

Abstract

Control valve for mass flows of fluids, with a valve housing with inflow ports opening into an inflow chamber for the fluid under high pressure and / or high temperature, with outflow ports leading off from an outflow chamber for the fluid flowing out at reduced pressure and / or reduced temperature, with an inflow and outflow chamber connecting valve insert, as well as with a provided in the valve insert, by means of a drive from a " closed position " in an " open position " axially displaceable valve stem surrounded by a perforated throttle basket for at least one control stage, the inside of the valve insert and the outside of the valve stem each having an approximately equal length for each regulating stage, the perforated throttle basket for each control stage each having a number of throughflow openings and correspondingly at least one outflow opening and in particular a last stage is provided as the outflow stage, characterized in that the perforated throttle basket (15) in the region of the outflow opening (17) of each control stage (a, b, c, ...) has an indentation (18 ), and that the valve stem (11) via the " open position " out into an " overflow position " is movable, in which the indentations (18) form flow bypasses (20) lying in the region of the ring webs (9).

Description

A control valve for mass flows of fluids, comprising a valve housing with inlet opening for the fluid under high pressure and / or high temperature, opening into an inflow chamber, having outflow outlets for the fluid which has reduced pressure and / or reduced temperature, with an inflow outlet. and the outflow chamber connecting valve insert, as well as with a provided in the valve insert, by means of a drive from a "closed position" into an "open position" axially displaceable, surrounded by a Lochdrosselkorb for at least one control valve stem, wherein the inside of the valve core and the outside of the valve stem for each control stage each have an approximately equally long recess, the pit choke for each control stage each having a number of flow openings and corresponding thereto in each case at least one outflow opening, and wherein in particular a last stage as Abstr ömstufe is provided.

In special operating conditions - such occur, for example, in the start-up state, in operating conditions of various test runs or in the power plant area as in a quick-closing of the turbine - over the control valve over the normal normal operation of the control valve usually to be controlled mass flows significantly larger mass flows safely dissipate. This requires a special design of the control valve. Out DE 2 209 230 is such a multi-stage control valve for superheated steam is known in which in a valve housing with a high pressure fluid inlet chamber and a discharge chamber for the fluid with reduced pressure, a tubular valve insert is located with valve seat in which a surrounded by a tubular choke Valve stem is arranged, which is to control the fluid flow with a means of a drive axially from a "closed position" in an "open position" and vice versa movable, and the outer surface abuts with at least partial positive engagement on the inner surface of the tubular valve core. Another control valve is out of the EP 0 053 290 A1 known, which comprises an outflow stage for a throttle body with an axial movable throttle body with control stages.

The inner wall of the tubular valve insert and the outer wall of the valve stem have arranged to form control stages from each other at equal intervals, a number of ring chambers forming recesses with an axial extent corresponding to the lifting height. Each of the control stages is formed by groups of flow openings, wherein the distances of the groups from each other correspond to the distances of the annular chambers from each other and these in turn the lifting height. Each of the groups of flow-through openings is associated with at least one overflow opening, which is offset relative to the group arranged so that this after opening of the valve allows the passage of the fluid from the previous annular chamber in the following. The cascade-like arrangement enables a multi-stage pressure reduction, that this pressure reduction generally applies to fluids, is obvious to the expert. A disadvantage of this arrangement is that these valves would be used in uneconomically enlarged design for the safe dissipation of in special operating conditions only exceptionally incurred larger mass flows.

This is where the invention is based, which is based on the task to further develop the generic control valve so that it allows to master the increased mass flows resulting in special operating conditions in a design for normal operating condition.

This task is solved for a control valve, defined by the features listed in the preamble of the independent main claim, by the features contained in its characteristics. Advantageous developments and preferred embodiments describe the dependent claims.

The perforated throttle basket has, for each control stage, a region with hole-shaped flow-through openings whose length corresponds to the first stroke of the valve stem, so that, in cooperation with the annular webs separating the recess provided on the inside of the housing tube, the pulling of the valve stem successively clears the region of the throughflow openings of the perforated throttle body given and thus the rules are effected.

Subsequently to the region with hole-shaped flow-through openings of each control stage, the orifice throttle basket has an annular indentation whose length corresponds to a second stroke of the valve stem. This arrangement is repeated at equal intervals in multi-stage control valves, wherein the annular indentation in each of the stages extends from the end of the region with hole-shaped throughflow openings of one stage to the beginning of the region of the throughflow openings of the following control stage. It is self-evident that the region provided with the flow-through openings during normal operation in the normal operating state with positive engagement on the annular surface of the annular web between two successive recesses of the valve stem is applied to prevent vibrations of valve stem with hole throttle basket.

In the normal operating state, depending on the control specification, the valve stem is pulled with the port throttle cage from the "closed position" to an "open position", the control range of the control valve lying between the "closed position" and this "open position". In this control range between closed position "and" open position ", the port choke with its lateral surface abuts against the annular surface forming the inner surface of the valve housing annular surface of successive recesses, so that the fluid flow is forced in a known manner, their way through the flow openings to take in the annular chamber-shaped recess of the valve stem and from there through the outflow opening in the next of the annular chamber-shaped recesses of the valve housing to get from there to the next stage of the throttle cascade. By this overflow and associated deflections of the desired pressure reduction for each of the stages is achieved in normal operating conditions.

If a special operating state occurs and therefore considerably greater mass flow is to be mastered, the valve stem with the port throttle basket is pulled into an "overflow position". Then the indentations come into effect, which open a "bypass" to Lochdrosselstrecke. In each of the stages of such a control valve, the fluid can now pass at increased cross-section without deflections of the inlet chamber to the outlet chamber. Thus, a control valve of predetermined size is able to cope with respect to its "normal design" significantly larger mass flow. It comes as a result of the increase in the flow velocity to a pressure reduction, which is desired, and which, if the maximum mass flow can be estimated within certain limits by the size of the indentations of Lochdrosselkorbes can be predetermined.

The lengths of the intake areas allowing the outflow of large mass flows in the inner wall of the valve insert and lengths of the areas of the throttle bores behave in each of the control stages as at least 1: 1. Therefore, the maximum travel distance that the valve stem with the orifice choke needs to be pulled in the first stroke to the "open position" to reach the limit of the "first open stage" is at most equal to the distance that the valve stem reaches in the second stroke the limit height of the "overflow", in which the maximum mass flow can flow, can be pulled.

To further stabilize the valve core surrounding Lochdrosselkorbes, it is advantageous if at least three axially parallel support webs bridge the indentations. The outer surfaces of these support webs are applied to the inner lateral surfaces of the valve core and thus contribute to the partial positive engagement with the valve housing concern.

A particular advantage of this design is that the outflow of large mass flows over the bypasses of the control stages is not dependent on their number, and so do not have to be adapted to the outflow of in special operating conditions also significantly increased mass flows. This simplifies the production, which also makes it more economical.

The essence of the invention will become apparent in the 1 to 4 illustrated embodiments illustrated in more detail; show:

1 : Control valve for special operation; Section (left "closed position", right "overflow position");

2 : Control valve in normal operation; Section (left: "open position", right: "overflow position");

3 Detail of a control level (after 2 );

4 Detail control valve (section IV-IV / 3 - jumped).

The control valve 1 - in 1 shown so that its left half in "closed position" and its right half in "overflow" and in 2 so that its left half in "open position" and the right half in "overflow position is - shows in the" closed position "the valve cone 12 sealing in the valve seat 7 fitting, while in the "open position" of the valve cone 12 from the valve seat 7 has lifted off. In the "overflow position" is the valve stem 11 with perforated choke basket 15 pulled even further, so the bypasses 20 are open; a detailed representation of a control stage of the control valve 1 shows 3 ,

The control valve 1 has a (also multi-part) valve housing 2 in, into which an inflow pipe 3.1 flows into an inflow chamber 3 passes. The housing 2 further has a discharge nozzle 4.1 on, which is attached to the outflow chamber 4 followed. Inside the control valve 1 is an axial passage into which a tubular valve core 5 is used. This valve insert 5 take one with a poke choke basket 15 covered valve stem 11 on, which is connected via a valve linkage with a (not shown) drive. The drive causes the axial displacement of the valve stem 11 with the hole choke basket 15 from a "closed position" to the "open position", and beyond that into the "overflow position". There are valve insert 5 and valve stem 11 with perforated choke basket 15 designed so that at least two control levels a, b, c, .... are formed.

The tubular valve insert 5 is on his the valve stem 11 facing inside with recesses 8th provided that form annular chambers. These ring chambers 8th are in front of each other by circumferential ring lands 9 separated, whose inner diameter is such that the Lochdrosselkorb 15 with its lateral surface positively abuts against the inner surfaces. Corresponding points the valve stem 11 on his the valve core 5 facing outside the same length recesses 13 on, which also form annular chambers. The hole choke basket 15 is with flow openings 16 and outflow openings 17 Mistake.

That the control valve 1 flowing fluid passes through inlet port 3.1 and inflow chamber 3 a, flows through the flow openings 16 the first control stage a in this control stage associated annular chamber 13 of the valve stem 11 , and passes through the discharge opening 17 in the next stage b associated annular chamber 8th of the valve insert 5 from it through the flow openings 16 in the second control stage b associated annular chamber 13 of the valve stem 11 passes from there through the corresponding outflow openings 17 into the next of the ring chambers 8th to reach the control level c.

This flow continues from a control stage formed by such groups to the next control stage, wherein the thermodynamic state of the fluid changes from control stage to control stage. Here is the position of the valve stem 11 with the hole choke basket 15 between the "closed position" and the "open position" for the degree of change of state, so that a control function is achieved.

In order to be able to control larger mass flows occurring in special operating states, which are outside the control range of the control valve 1 lie, are for each of the groups a, b, c, ... bypasses 20 intended. Each of these bypasses 20 is from a collection 18 of the multiple throttle cage 15 formed, between the flow-through 16 and the discharge openings 17 , this is arranged enclosing. When moving the valve stem 11 with perforated choke basket 15 in the "overflow" so bypasses 20 free, which is an overflow from the annular chamber of a group forming recess 8th of the valve insert 5 to the annular chamber of the following group (or to the outflow chamber 4 ) free.

This release is effected by the fact that the ring land 9 in the area of the opposite to the lateral surface of the multiple throttle cage 15 jumping backwards 18 in this position no longer abuts against this lateral surface and so a flow channel as a bypass 20 between the annular chambers of two successive indents 18 opens.

The 4 shows a (sprouted) cross section through the valve core 5 a control valve 1 in which the valve stem 11 with the hole choke basket 15 is arranged according to this invention. In the area of the indents 18 of the hole throttle basket 15 provide axially parallel support webs 19 - In the figure, 4 webs are shown - stabilizing components that the Lochdrosselkorb 15 in special operating conditions in the area of the annular webs 9 against the inner circumferential surface of the valve core 5 support. Between the indents 18 (indicated by dashed lines) and the corresponding ring lands 9 open the bypass routes 20 , which thereby allow the overflow of the resulting larger mass flows.

LIST OF REFERENCE NUMBERS

01

control valve

02

valve housing

03

inflow

03.1

Einströmstutzen

04

current chamber

04.1

outflow

05

tubular valve insert

06

Housing tube mounting

07

valve seat

08

Ring chamber housing tube

09

ring land

10

drive linkage

11

valve stem

12

valve cone

13

Annular chamber valve stem

14

15

Hole throttle basket

16

flow-through

17

outflow

18

collection

19

supporting web

20

bypass

a, b, c

control stages

Claims (8)

A control valve for mass flows of fluids, comprising a valve housing with inlet opening for the fluid under high pressure and / or high temperature, opening into an inflow chamber, having outflow outlets for the fluid which has reduced pressure and / or reduced temperature, with an inflow outlet. and outflow chamber connecting valve insert, and with a in the valve core provided, by means of a drive from a "closed position" into an "open position" axially displaceable, surrounded by a Lochdrosselkorb for at least one control valve stem, wherein the inside of the valve core and the outside of the valve stem for each control stage each have an approximately equally long recess, wherein the Lochdrosselkorb for each control stage in each case has a number of flow openings and corresponding thereto in each case at least one outflow opening, and wherein in particular a last stage is provided as Abströmstufe, characterized in that the Lochdrosselkorb ( 15 ) in the region of the discharge opening ( 17 ) each control stage (a, b, c, ...) a collection formed by the receipts ( 18 ), and that the valve stem ( 11 ) is movable beyond the "open position" into an "overflow position" in which the indents ( 18 ) in the area of the ring lands ( 9 ) lying flow bypasses ( 20 ) form. Control valve according to claim 1, characterized in that for each control stage, the length of the annular chamber-like indents ( 8th ) in the valve core ( 5 ) is at least equal to, preferably larger, than the length of the through-flow openings ( 16 ) provided area of the Lochdrosselkorbes ( 15 ) each of the control levels (a, b, c ...). Control valve according to claim 1 or 2, characterized in that for each of the control stages, the associated annular webs ( 9 ) the corresponding indents ( 18 ) of the valve stem ( 11 ) with hole choke basket ( 15 ) in the "overflow position" approximately in the middle. Control valve according to claim 1, 2 or 3, characterized in that the feeder ( 18 ) of evenly distributed axially extending support webs ( 19 ) is bridged, the outer surface of the lateral surface of the Lochdrosselkorbes ( 15 ), preferably three support webs ( 19 ) are arranged lying at an angular distance of 120 °. Control valve according to one of claims 1 to 4, characterized in that a barrier is provided which the stroke of valve stem ( 11 ) with hole choke basket ( 15 ) between "closed position" and "open position" is allowed, and which is solvable in special operating states to the throttle basket ( 15 ) axially beyond the "open position" to move so far that the indents ( 18 ) in cooperation with the ring bridges ( 9 ) the flow bypasses ( 20 ) form the "overflow position". Control valve according to claim 5, characterized in that the lock is manually releasable. Control valve according to claim 5, characterized in that the barrier is automatically detachable by means of a monitoring. Control valve according to claim 7, characterized in that the monitoring is computer-aided.

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