DE2436090C3 - Pressure medium-controlled control valve for steam power plants by means of an auxiliary valve - Google Patents

Description

so that the opening acceleration of the valve piston 8 can be limited.

Both the pilot piston 12 and the valve piston 8 are each on the spring side with axial Provided sealing bonds that have the effect that in the opening end position no more pressure medium on the Control lines 25,61,29 can flow out.

The closing process is initiated by activation of the auxiliary control valve 84 in switching position "Z", with the effect that pressure medium flows over the control line 25, 61, 62 into the rod space 24 the pilot piston 12 is first brought into the closed position and at the same time the cylinder chamber 42 via the Spindle guide gap filled.

When there is a corresponding pressure build-up in the cylinder space 42, the valve piston 8 is activated by the prestressing force

Piston spring 11 moved away from the opening end position and through increased refilling via channels 49, 51, 52 and via the gap in the valve piston guide Switch characteristics pressed in closed position.

The valve shown is characterized by a short overall length and straight flow, which is brought about by the tubular design of the housing 1 and the guide cylinder 6 centrally mounted therein by means of a web 70. As an alternative to the version shown in the figure, the quick-opening valves are also conceivable in corner construction. All moving valve parts as well as the bearing points in the housing are made of heat-resistant material and hardened; the compression springs can be provided for temperatures up to 560 ⁰ C, if you z. B. made from Nimonic.

1 sheet of drawings

Claims (1)

Claim: By means of an auxiliary valve, pressure-medium-controlled valve with a valve that forms the valve closure body, in a guide cylinder sliding and loaded by a spring provided there in the closing direction Valve piston, the guide cylinder of which with the side of the valve piston facing away from the valve seat forms a pressure chamber and which is provided on the side of the pressure chamber with a valve rod which slides in a housing bore whose end facing away from the valve piston with the auxiliary valve is in flow connection, with flow connections between the control openings of the Help valve and the housing bore and the pressure chamber on the one hand and the inlet side of the Main valve on the other hand exist and at least the flow connection between the pressure chamber and the control opening of the auxiliary valve leading to an unpressurized outlet, a throttle point has, and with a guided in the auxiliary piston, designed as a stepped piston, a pilot opening to the main valve cross-section dominating the pre-stroke valve closure body, whose part having the smaller cross section represents the seated person and on the side facing away from the seat end through an inner bore of the valve rod of the Housing bore and on the other side directly through a cross hole in the valve piston the annular surface of the step is acted upon by the propellant, r is, with the application of the Valve as a combined start-up and quick-closing device for steam and gas turbines the valve piston one until it reaches one assigned pressure on the downstream side in the closing direction holding lock is, in that the housing bore and the pressure chamber are connected in series in terms of flow, so that the throttle point lies in between, this as a gap between the valve rod and the Housing bore is formed and another throttling, adjustable in the assembled state of the valve Flow connection directly from the inlet side of the valve to the pressure chamber of the valve piston exists, so that this additional flow connection and the gap between the valve rod and the housing bore a definition of the cylinder pressure in the pressure chamber and thus the as opening pressure to the effect coming back pressure on the downstream side in a certain Form the relationship to the propellant pressure causing the flow cascade, according to patent 23 03 511, characterized in that for using the valve as a quick opening valve the transverse bore (19) in the valve piston (8) between the pilot piston (12) its seat surrounding pressure chamber (30) of the valve piston (8) and the pressure chamber (42) of the Guide cylinder (6) is arranged. The invention relates to a control valve according to the im General term of the patent claim listed Merk ' male according to patent 23 03 511, It will be ntin Among other things in interaction with steam ' turbine systems there quick-opening valve a ' set where, for procedural reasons, the steam flow is not interrupted even briefly allowed. The task of the quick opening valve lies in this in that, with intentional or unintentional triggering of the turbine quick-closing valves, the steam flow as possible instantly in the bypass to divert the turbine to the low-pressure side. Because of this you have to the opening times of the quick-opening valves must be adapted to the ίο operating times of the quick-closing valves. Naturally, the quick-opening valves are only activated in the event of malfunctions or during start-up and Shutdown of the steam turbines claimed, so that they over the much longer period are closed. Conventional Schnellöffnurigsventi-Ic with mechanical-hydraulic drive are here due to their spindle feedthroughs, stuffing boxes, etc. exposed to conditions that affect the functional reliability can affect. The object of the invention is to provide a quick-opening valve to create, in which no moving valve parts that come into contact with steam are sealed against the atmosphere Need to become. There should also be no leakage steam to the outside when the valve is closed or open be discharged so that there is no risk of possible deposits in the valve guides. According to the invention, this object is achieved in a valve of the type mentioned at the outset by the characterizing features of the claim. The invention is explained below using the exemplary embodiment shown in the drawing, wherein FIG.] the valve according to the invention, FIG. 1 a and I b show switching positions of the auxiliary control valve. The pressure medium flows into the tubular in the direction of the arrow trained valve housing 1, with the valve piston 8 closed, is also via the control line 62, the Auxiliary control valve 84 and control line 61 in the rod space delimited by rod 48 of valve piston 8 24 Pressure built up, also via the 'jypass bores 49, 51,52 in through the bushing 60 of the guide cylinder 6 and the valve piston 8 delimited cylinder space 42. By the application of pressure, the valve piston 8 with its seat 43 is reinforced against the Valve seat ring 53 is printed, as is the pilot piston 12 against the seat part screwed into the valve piston 8 15. so that no pressure medium can flow over to the low-pressure side 37. If the auxiliary control valve is now switched, hydraulically or electrically, from position "Z" to "A" and the pressure in the rod space 24 is thus reduced via the line 29, that predominates through the bore 19 in the pressure space 30 in the valve piston 8 on the annular surface 20 of the pilot piston 12 acting pressure the biasing force of the compression spring 17 and moves the pilot piston 12 in the open position. By now opened pilot control pressure medium can flow to the low pressure side 37 from the cylinder chamber 42, which at the same time? U a reduction in pressure in the cylinder chamber 42 carries. The unchanged pressure force in the valve housing 1 against the effective annular surface 50 of the valve piston 8 now outweighs the closing forces of the piston spring II And pressure chamber in cylinder 42 and brings the Valve piston 8 with switch characteristics in opening S ' Position. By adjusting the throttling by means of the throttle screw 44, the cylinder space 42 can be controlled by the Einlrittsseite 16 set a back pressure and