Volume flow regulating valve

Abstract

A volume flow regulating valve for controlling the volume flow of a fluid medium in two outflow ducts. The volume flow regulating valve is composed of a cylinder with a dual piston mounted axially displaceably in the cylinder, with a central pressure chamber being formed in the region of the barbell-shaped central piece of the dual piston. Aside from an inlet for the fluid medium, it is also the case that the two outlet ducts are provided at the central pressure chamber. The outlet ducts are arranged on the cylinder with such an axial spacing that—when the dual piston is situated in a central position in relation to the two outlet ducts—the first outlet duct—preferably partially covered by the first piston—and the second outlet duct—preferably partially covered by the second piston—each open up an equal opening cross-sectional area.

Claims

1. A volume flow regulating valve, comprising: a cylinder having a cavity; a dumbbell-shaped double piston guided in the cavity of the cylinder, the double piston having a first piston and a second piston, the pistons being fixedly connected together by a narrowed center member, wherein a central pressure chamber is formed in the cavity in a region of the narrowed center member, each piston having an end face remote from the narrow center member; a first peripheral pressure chamber and a second peripheral pressure chamber in the cylinder, the first peripheral chamber being bounded by the end face of the first piston and the second peripheral chamber being bounded by the end face of the second piston; and a feed channel and a first drain channel in the cylinder respectively for feeding a fluid medium to and draining the fluid medium from the central chamber; a second drain channel in the cylinder for draining the fluid medium from the central pressure chamber, wherein the first drain channel and the second drain channel are arranged at the cylinder with an axial spacing so that when the double piston is disposed in a center setting with respect to the two drain channels the first drain channel and the second drain channel respectively free an equal opening cross-section area; a first pressure channel provided to supply a static pressure in the first drain channel to the second peripheral pressure chamber, wherein the first pressure channel has an end at an opening in a wall of the first drain channel so as to detect the static pressure in the first drain channel; a second pressure channel provided to supply a static pressure in the second drain channel to the first peripheral pressure chamber, wherein the second pressure channel has an end at an opening in a wall of the second drain channel so as to detect the static pressure in the second drain channel; a first pitot tube arranged in the first drain channel so that the fluid medium flows into the first pitot tube and the first pitot tube detects total pressure in the first drain channel; a second pitot tube arranged in the second drain channel so that the fluid medium flows into the second pitot tube and the second pitot tube detects total pressure in the second drain channel; a first plunger mounted in the first peripheral pressure chamber to be axially displaceable for action on the end face of the first piston, wherein the first plunger is loaded by the total pressure in the first drain channel; and a second plunger mounted in the second peripheral pressure chamber to be axially displaceable for action on the end face of the second piston, wherein the second plunger is loaded by the total pressure in the second drain channel.

2. The volume flow regulating valve according to claim 1, wherein in the center setting the first piston partially covers the first drain channel and the second piston partially covers the second drain channel.

3. The volume flow regulating valve according to claim 1, wherein the volume flow regulating valve is configured for pressures up to 2,000 bar.

4. The volume flow regulating valve according to claim 1, further comprising a respective spring arranged in each of the first and second peripheral pressure chambers so as to hold the double piston in the center setting and so that the double piston is axially displaceable.

5. A chock for rotatable mounting of a roll pin of a roll in a roll stand for a rolling material to be rolled, comprising: a cylindrical receiving chamber for receiving the roll pin; a first feed channel and a second feed channel for feed of coolant and/or lubricant to the receiving chamber; and an element for regulating volume flow of the coolant and/or lubricant in the first and second feed channels; wherein the element is a volume flow regulating valve according to claim 1; and the first drain channel of the volume flow regulating valve is connected with the first feed channel and the second drain channel is connected with the second feed channel.

6. The chock according to claim 5, wherein at least one of the first and second feed channels communicates with a hydrostatic pocket formed at an inner wall of the receiving chamber for the roll pin.

7. The chock according to claim 6, further comprising a bearing bush that spans the receiving space as a wear component; wherein the hydrostatic pocket is formed at an inner side of the bearing bush.

8. The chock according to claim 5, further comprising a pump for feeding the coolant and/or lubricant via the feed channel for feeding the fluid medium to the central pressure chamber of the volume flow regulating valve.

9. The chock according to claim 8, wherein the pump feeds the coolant and/or lubricant at pressures up to 2,000 bar.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Three figures accompany the description, wherein:

(2) FIG. 1 shows the volume flow regulating valve according to the invention;

(3) FIG. 2 shows a detail illustration with respect to FIG. 1; and

(4) FIG. 3 shows a chock for rotatable mounting of a roll pin of a roll in connection with the regulating valve according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(5) The invention is described in detail in the following in the form of embodiments with reference to the mentioned figures. The same technical elements are denoted by the same reference numerals in all figures.

(6) FIG. 1 shows the volume flow regulating valve 100 according to the invention. It substantially consists of a cylinder 110 in which a dumbbell-shaped double piston 120 is mounted to be axially displaceable. The term “axially” is used in the context of the invention for the direction of movement of the double piston. The double piston 120 consists of a first piston 120-1 and a second piston 120-2, which are fixedly connected together by way of a narrowed centre member 126. The first and second pistons to that extent lie as tightly as possible against the cylinder wall. A central pressure chamber 130 of the volume flow regulating valve 100 is formed in the region of the narrowed centre member 126.

(7) A first peripheral pressure chamber 150-1 and a second peripheral pressure chamber 150-2 are formed in the end regions of the cylinder and the pressure chambers are respectively bounded by the end faces, which are remote from the centre member 126, of the first and second pistons. A feed channel 160 is formed at a central point, preferably at half the height of the cavity of the cylinder 110, for the feed of a fluid medium, for example a coolant and/or lubricant, to the central chamber 130 with the help of a pump device 250. A first drain channel 170-1 and a second drain channel 170-2 for draining the fluid medium from the central pressure chamber 130 are formed in the cylinder wall. The first and second drain channels 170-1 and 170-2 have the same axial spacing d from the two sides of the feed channel 160. At the same time, the length L of the centre member 126 of the double piston 120 preferably corresponds with the spacing 2d of the centre axes of the first and second drain channels 170-1 and 170-2. In this way it is ensured that when the double piston 120 is disposed in a centre setting the first drain channel 170-1 is closed in such a way by the first piston 120-1, and at the same time the second drain channel 170-2 is also closed in such a way by the second piston 120-2, that the two pistons free the same opening cross-section area.

(8) A respective spring 140 is preferably arranged in each of the peripheral pressure chambers 150-1 and 150-2 so as to hold the double piston in a centre setting, particularly in the case of non-operation of the volume flow regulating valve. However, the springs 140 do not hinder the basic possibility of axial displacement of the double piston 120 within the cylinder 110.

(9) The above-mentioned object of the invention, namely ensuring the same volume flows in the first and second drain channels 170-1 and 170-2 even in the case of different pressure ratios thereat, is fulfilled in particular in that the peripheral pressure chambers 150-1 and 150-2 of the volume flow regulating valve are loaded in suitable manner with specific pressures. In concrete terms, for this purpose the first peripheral pressure chamber 150-1 is loaded with the static pressure in the second drain channel 170-2. In analogous manner, the second peripheral pressure chamber 150-2 is loaded with the static pressure in the first drain channel 170-1. The loading is carried out by way of a respectively provided first pressure channel 180-1 and second pressure channel 180-2.

(10) In addition, a first plunger 190-1 is mounted in the first pressure chamber 150-1 to be axially displaceable for action on the end face, which bounds the first peripheral pressure chamber, of the first piston 120-1 of the double piston. During operation of the regulating valve the first plunger 190-1 is loaded by way of a pressure channel with the total pressure in the first drain channel 170-1. In analogous manner, a second plunger 190-2 is mounted in the second peripheral pressure chamber 150-2 to be axially displaceable for action on the end face, which bounds the second peripheral pressure chamber 150-2, of the second piston 120-2 of the double piston. Again, in analogous manner the second plunger 190-2 is loaded by way of a pressure channel with the total pressure in the second drain channel 170-2. The pressure channels are illustrated in FIG. 1 as dashed lines.

(11) FIG. 2 shows the connection of the pressure channels for the static and total pressure with the first drain channel 170-1 or the second drain channel 170-2. In concrete terms it can be seen that a fluid medium flows in the drain channels 170-1 and 170-2. This medium can be a coolant and/or lubricant, which flows from the central pressure chamber 130 to a consumer, for example a chock for rotatable mounting of a roll pin. In that case, the fluid medium within the drain channels exhibits a speed distribution as can be seen in FIG. 2 by the reference numeral 1. In order to detect the total pressure p.sub.Total in the drain channel a pitot probe arranged so that the fluid medium flows into the pitot probe is provided. In addition, provided at the wall of the drain channel 170 is an opening, which represents the end of the first pressure channel 180-1 or second pressure channel 180-2, for detection of the static pressure p.sub.Stat in the drain channel.

(12) During operation of the volume flow regulating valve 100 the double piston 120 sets itself automatically or independently in correspondence with a balance of the forces acting thereon. This force equilibrium arises as a consequence of, in particular, the forces acting on the end faces, which are remote from the centre member 126, of the first piston 120-1 and second piston 120-2. The forces are on the one hand the force resulting from the action of the static pressures on the end faces of the first and second pistons and the force exerted by the plungers on the same end faces. In addition, the force exerted by the springs 140 on the same end faces has an influence on the force equilibrium. The force equilibrium determines the axial position of the double cylinder and thus also the ratio of the degree of opening of the first drain channel to the degree of opening of the second drain channel. In correspondence of this ratio of the degrees of opening, the volume flows in the first and second drain channels 170-1 and 170-2 can be set to be equal in amount.

(13) FIG. 3 shows the mentioned use of the volume flow regulating valve 100 in accordance with the invention in connection with a chock 200. The chock 200 serves for rotatable mounting of a roll pin 300 of a roll in a roll stand for the rolling of material to be rolled. The chock 200 has a cylindrical receiving space 210 in which the roll pin 300 is rotatably mounted. The cylindrical receiving space is typically spanned by a bearing bush 220 inserted as a wear component into the chock 200. Several, typically two, hydrostatic pockets 2 and 3, through which the coolant and/or lubricant is pumped under high pressure into the receiving chamber 210, more precisely into the annular gap between the bearing bush 220 and the roll pin 300, are formed at the inner wall of the bearing bush 220. For this purpose the first drain channel 170-1 of the volume flow regulating valve, also termed first feed channel, is connected with the first hydrostatic pocket 2 and the second drain channel 170-2 of the volume flow regulating valve, also termed second feed channel, is connected with the second hydrostatic pocket 3.

(14) It is advantageous, particularly for use of the volume flow regulating valve 100 according to the invention in conjunction with the chock 200, if the volume flow regulating valve is designed for pressures up to 2,000 bars.

REFERENCE NUMERAL LIST

(15) 1 speed profile

(16) 2 hydrostatic pocket

(17) 3 hydrostatic pocket

(18) 100 volume flow regulating valve

(19) 110 cylinder

(20) 120 double piston

(21) 120-1 first piston

(22) 120-2 second piston

(23) 126 centre member

(24) 130 central pressure chamber

(25) 140 spring

(26) 150-1 first peripheral pressure chamber

(27) 150-2 second peripheral pressure chamber

(28) 160 feed channel for central pressure chamber

(29) 170-1 first drain channel for fluid medium from the central pressure chamber

(30) 170-2 second drain channel for fluid medium from the central pressure chamber

(31) 180-1 first pressure channel

(32) 180-2 second pressure channel

(33) 190-1 first plunger

(34) 190-2 second plunger

(35) 200 chock

(36) 210 cylindrical receiving space

(37) 220 bearing bush

(38) 250 pump device

(39) 300 roll pin

(40) d axial spacing

(41) L length of the centre member

(42) p.sub.Total total pressure

(43) p.sub.Stat static pressure