RU2179678C2 - Adjusting valve - Google Patents

Abstract

FIELD: adjustment of flow rate of medium. SUBSTANCE: adjusting valve has body with branch pipes for inlet and outlet of medium; outer is secured on body. This bush has rectangular ports with longitudinal and side edges. Inner bush is located in outer bush and is engageable with drive shaft. Inner bush has shaped ports. Bushes have additional ports in form of slots shifted relative to longitudinal edges in transversal direction. Slots of inner and outer bushes are matched when valve is fully open. EFFECT: improved functional parameters of valve. 3 dwg

Description

 The invention relates to the field of energy, to means for controlling the flow rate of the medium and can be used in the regeneration schemes of steam turbines of powerful power units of TPPs and nuclear power plants, as well as power supply units of steam boilers of pro-energetics.

 A known valve for regulating the flow of water, comprising a housing with an external sleeve fixed in it, in which rectangular windows with longitudinal and lateral edges are made, and an internal sleeve, which is formed with shaped windows, and which is articulated with the drive shaft, is made in the external sleeve. When the inner sleeve is rotated, the position of the shaped windows relative to the rectangular ones and the corresponding passage section for the controlled environment / 1 / change.

 A disadvantage of the known valve for controlling the flow of water is reduced reliability due to the possible jamming of the inner sleeve in the outer one. One of the main causes of jamming is the deformation of the inner sleeve under the influence of a pressure differential, reaching a maximum value at starting conditions at low flow rates. Another cause of valve jamming is the ingress of foreign particles into the gap between the bushings.

 A control valve is known, comprising a housing with an outer sleeve fixed in it, in which rectangular windows are made, and an inner sleeve placed in the outer sleeve and articulated with the drive shaft, in which shaped windows are made, and the end of the outer surface of the inner sleeve is tapered / 2 /. This device is taken as a prototype.

 The disadvantage of the prototype is the impossibility of setting the dimensions of the longitudinal edges of rectangular and shaped windows, providing optimal functional parameters of the valve in terms of the range and accuracy of flow control, and, as a result, the inability to achieve a linear dependence of flow on the angle of rotation of the shaft.

 The objective of the invention is to improve the functional parameters of the valve by expanding the range and improving the accuracy of flow control.

 The technical result is achieved by the fact that in the control valve, comprising a housing with medium inlet and outlet pipes, with an external sleeve fixed in it, in which rectangular windows with longitudinal and lateral edges are made, and an internal sleeve placed in the external sleeve and articulated with the drive shaft, in which shaped windows are made, additional windows in the form of grooves parallel to the longitudinal edges of rectangular windows and offset relative to the longitudinal edges in the transverse direction are made in the outer and inner bushes laziness, and the grooves of the inner and outer bushings are aligned when the valve is fully open.

 The invention is illustrated by drawings, in which Fig. 1 shows a longitudinal section of a valve, Fig. 2 is a scan of the working surfaces of the inner and outer bushings, and Fig. 3 is a graph of the flow rate, differential pressure and flow section in the valve versus the angle of rotation of the shaft and relative positions windows of both bushings.

 The control valve comprises a housing 1 with an inlet pipe 2 and an outlet pipe 3. An external sleeve 4 is fixed in the housing 1, pressed into the gasket 7 by fitting into the holes 5, 6 of the housing.

 In the outer sleeve 4 there are rectangular windows 8 with longitudinal and lateral edges and additional windows in the form of grooves 9 parallel to the longitudinal edges of the rectangular windows 8 and offset relative to the longitudinal edges in the transverse direction (in Fig. 1, the grooves 9 are shown by a conditional contour, since they are closed the walls of the inner sleeve). Rectangular windows 8 and additional windows in the form of grooves 9 - paired; in addition to those depicted, the same windows 8a and 9a are placed in the wall of the outer sleeve 4 diametrically opposite to the windows 8 and 9 (figure 2). In the outer sleeve 4 is rotatably disposed an inner sleeve 10 of a cylindrical shape with a collar 11 pressed against the upper end of the outer sleeve 4 by means of a spring 12, and articulated with the drive shaft 13.

 Shaped windows 14, 14a and additional windows are made in the inner sleeve 10 in the form of grooves 15, 15a parallel to the longitudinal edges of the rectangular windows 8 and offset relative to the longitudinal edges in the transverse direction.

 The grooves 15 of the inner sleeve 10 and the grooves 9 of the outer sleeve 4 are aligned when the valve is fully open, the shaped windows 14 are predominantly T-shaped or L-shaped.

 The mutual arrangement of the windows and grooves of the outer and inner bushings is graphically shown in FIG. 2, showing the combined scan of the bushings 4 and 10, a view from the side of the bush 4. The bushings 4 and 10 are shown at the moment the valve begins to open, when only 10 are open in the direction of arrow 16 sections 17, 17a of the windows 14, 14a of the inner sleeve 10. The longitudinal edges of the grooves 9, 9a are offset from the longitudinal edges of the windows 8, 8a of the outer sleeve in the transverse direction (circumference); the edges of the grooves 15, 15a of the inner sleeve are likewise offset relative to the corresponding edges of the shaped holes 14, 14a. Such an offset provides the possibility of minimizing the weakening of the bushings 4, 10 by windows and maximizing the stiffness of these bushings.

 The control valve operates as follows.

 The working medium, in this case water, is supplied under pressure through the inlet pipe 2 into the annular cavity, from where it passes through the rectangular windows 8 of the outer sleeve 4 and the open part of the shaped windows 14 of the inner sleeve 10 into the internal cavity of the valve and then through the outlet pipe 3 is fed into the outlet pipeline.

 If the water level in the heater (boiler) deviates from the required one, for example, as a result of a change in water flow, the level control sensor sends a signal to turn on the valve actuator, which, through the actuator, drives the handle of the drive shaft 13, transmits rotation to the inner sleeve 10. Rotation of the inner sleeve 10 continues until the area of the open part of the shaped windows 14, combined with the rectangular windows 8, becomes required by the conditions for ensuring a changed flow rate. Upon reaching the previous water level in the heater (boiler), the control sensors give a signal to turn off the valve actuator.

 If, according to the operating conditions, it is necessary to discharge the load or stop the unit (the most dangerous mode from the point of view of jamming), the valve starts to close, the pressure drop, and therefore the deformation of the inner sleeve 10 increases, reaching maximum values, however, the valve will not jam.

 The operation of the valve is illustrated in Fig. 3 combined graphs of changes in relative values of flow rate (18), cross-section at the control holes (19) and pressure drop in the valve (20) (ordinate axis) depending on the angle of rotation of the inner sleeve (abscissa axis), except 3, in its upper part, for clarity, the relative positions of the holes 8, 9 and 14, 15 corresponding to the rotation angles of the shaft and the inner sleeve are shown (see FIG. 2).

In the initial phase of rotation of the spool (in this case, up to 36-40 ^o ), only holes 14 and 8 work, this ensures the accuracy and sensitivity of the regulation of small flows.

 At large angles of rotation, holes (windows and grooves) 15 and 9 are connected, which provides a faster increase in the total cross section of the throttling holes and is functionally equivalent to a sharp increase in the size of the section of the window 14 parallel to the axis of the shaft and bushings, but without reducing stiffness.

 The rapid increase in cross-section ensures linear dependence of the flow on the angle of rotation, which helps to increase the accuracy of regulation at high costs.

Sources of information
1. SU 1043403 A, 09/23/1983.

 2. SU 1667017 A, 07.30.1991.

Claims (1)

 A control valve, comprising a housing with medium inlet and outlet nozzles with an external sleeve fixed in it, in which rectangular windows with longitudinal and lateral edges are made, and an internal sleeve, which is formed in the external sleeve and articulated with a drive shaft, in which shaped windows are made, characterized in that in the outer and inner bushes additional windows are made in the form of grooves parallel to the longitudinal edges of rectangular windows and offset relative to the longitudinal edges in the transverse direction, with grooves inside The lower and outer bushings are aligned when the valve is fully open.

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