Control valve, in particular for use in cooling paths

Abstract

A control valve for adjusting the cross-sectional area of flow in at least one pipe, in particular for highly dynamic control of the coolant volume for cooling sections in rolling mills, includes a valve body, at least one valve seat and a positioning actuator configured for modifying the position of the valve body. The positioning actuator includes a linear electric motor in order to achieve reproducible response behavior, short response times and high positioning precision of the control valve.

Claims

1. A control valve for adjusting a cross-sectional area of flow in a pipe, the control valve comprising: a valve body, wherein a geometric shape of the valve body determines a flow characteristic of the control valve; a valve seat; and a positioning actuator configure to modify a position of the valve body, the positioning actuator including a synchronus linear electric motor and a rod-shaped actuating element directly connected to the valve body without any intermediate couplings, the synchronous linear electric motor having a coil and a permanent magnet, the coil being stationarily disposed, the permanent magnet being disposed on the actuating element, wherein the permanent magnet is a portion of the rod-shaped actuating element, the positioning actuator further comprising a position regulator for the synchronous linear electric motor permitting accurate adjustment of the control valve in response to fluctuations in pressure and volume of a flow medium in the control valve.

2. The control valve as claimed in claim 1, wherein the rod-shaped actuating element is movable along a translational movement.

3. The control valve as claimed in claim 1, wherein the position actuator includes a diaphragm actuator with a diaphragm having a first side placeable under load by a pressure medium.

4. The control valve as claimed in claim 3, wherein the diaphragm is attached to an upper end of the rod-shaped actuating element.

5. The control valve as claimed hi claim 3, further comprising a spring having a force directed onto a second side of the diaphragm such that the second side of the diaphragm is spring-loaded by the spring.

6. A cooling section for a rolling mill comprising a pipe for guiding a liquid coolant, and a control valve as claimed in claim 1 arranged in the pipe for controlling a flow of liquid coolant through the pipe.

7. A control valve for adjusting a cross-sectional area of flow in a pipe, the control valve comprising: a valve body, wherein a geometric shape of the valve body determines a flow characteristic of the control valve; a valve seat; and a positioning actuator configured to modify a position of the valve body, the positioning actuator including a synchronous linear electric motor and a rod-shaped actuating element directly connected to the valve body, the synchronous linear electric motor having a coil and a permanent magnet, the coil being stationarily disposed, the permanent magnet being disposed on the actuating element as an integral part of the actuating element, the positioning actuator further comprising a position regulator for the synchronous linear electric motor permitting accurate adjustment of the control valve in response to fluctuations in pressure and volume of a flow medium in the control valve, wherein the position actuator further includes a diaphragm actuator with a diaphragm having a first side placeable under load by a pressure medium.

8. The control valve as claimed in claim 7, wherein the rod-shaped actuating element is movable along a translational movement.

9. The control valve as claimed in claim 7, wherein the diaphragm attached to an upper end of the rod-shaped actuating element.

10. The control valve as claimed in claim 7, further comprising a spring having a force directed onto a second side of the diaphragm such that the second side of the diaphragm is spring-loaded by the spring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A control valve according to the invention is explained in greater detail below with reference to the figures, in which:

(2) FIG. 1 shows a control valve according to the invention with linear motor,

(3) FIGS. 2A-D show various valve housings for a control valve with linear motor and

(4) FIGS. 3A-F show different embodiments of closure members for a control valve with linear motor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) The control valve (1) comprises a valve housing (2) with an inlet and outlet (2a, 2b), a closure member (3) and a valve seat (4). The valve stem (4a) connected to the closure member (3) is coupled outside the valve housing (2) with a rod-shaped actuating element (5). The actuating element (5) is guided in an actuator housing (6) for translational to and fro movement in a vertical direction in order to move the closure member (3) coupled with the actuating element (5) to and fro between a closed position shown in FIG. 1 and an open position.

(6) The downwardly tapering closure member (3) is constructed such that, in the closed position, it prevents flow between the closure member (3) and the valve seat (4). Raising the downwardly tapering closure member (3) creates an annular cross-sectional area of flow between the valve seat (4) and the closure member (3), which area, due to the cross-sectional shape of the closure member, becomes larger during movement into the fully open position.

(7) The positioning actuator (7, 8) comprises a linear motor (7) and a diaphragm actuator (8). The linear motor (7) is formed by a coil unit (7a) arranged stationarily in the actuator housing (6) and a permanent magnet unit (7b). The permanent magnet unit (7b) takes the form of an integral part of, namely a portion of, the rod-shaped actuating element (5). A position reoulator (10), i.e., position control means, for the linear motor (7) is provided in order to permit accurate adjustment of the control valve (1) despite fluctuations in the pressure and volume of the cooling medium controlled by the control valve.

(8) The diaphragm actuator (8) placed on and attached to the actuator housing (6) comprises a diaphragm (8a) which is clamped between the housing halves (8b, 8c) of the diaphragm housing (8d). The upper end of the rod-shaped actuating element (5) is guided into the diaphragm housing via a gas-tight bushing (8e) and attached centrally to the diaphragm (8a). The diaphragm (8a) can be placed under load from below with a pressure medium. The upper side of the diaphragm is loaded by springs (8f) which rest against the upper housing half (8b).

(9) The springs (8f) ensure that, in the event of a pressure drop in the lower chamber of the diaphragm actuator (8), the diaphragm (8a) is loaded in the closing direction of the control valve (1).

(10) FIGS. 2a to 2d show different embodiments of valve housings which are intended for three-way control valves. The embodiments according to FIGS. 2a and 2b in each case have a closure member which interacts with two valve seats. The embodiments according to FIGS. 2c and 2d have two closure members, each of which interacts with one valve seat.

(11) It should be noted that various embodiments of control valves merely distinctly reduce, but do not prevent, flow in the closed position. This amounts to a leakage volume which can very well be of the order of 10% of the nominal flow rate.

(12) FIGS. 3a-3f show different embodiments of the closure members which influence the flow characteristic. FIG. 3a shows a closure member in the form of a parabolic plug, FIG. 3b in the form of a perforated plug, FIG. 3c in the form of a perforated plug with perforated cage, FIG. 3d in the form of a perforated plug for a control valve of three-way design, FIG. 3e in the form of a lantern plug and FIG. 3f in the form of a lantern plug with pressure relief means.

(13) TABLE-US-00001 No. Description 1. Control valve 2. Valve housing 2a. Inlet 2b. Outlet 3. Closure member 4. Valve seat 4a. Valve stem 5. Actuating element 6. Actuator housing 7. Positioning actuator 7a. Coil unit 7b. Permanent magnet unit 8. Diaphragm actuator 8a. Diaphragm 8b, c. Housing halves 8d. Diaphragm housing 8e. Bushing 8f. Springs