WO1999001226A1

WO1999001226A1 - Spray valve

Info

Publication number: WO1999001226A1
Application number: PCT/GB1998/001943
Authority: WO
Inventors: Gordon Downey
Original assignee: Lechler Limited
Priority date: 1997-07-02
Filing date: 1998-07-01
Publication date: 1999-01-14
Also published as: AU8228398A; GB9713901D0

Abstract

The invention relates to spray valves (1) particularly for the direction of coolant against rolling rolls. During cold rolling there is an inevitable heating effect caused by the friction between a roll and the material being rolled that can distort the roll surface to provide a convex or a concave roll surface. Unless corrected the result would be the rolling of non-flat plate strip or foil. There are known valves and techniques for the selective spraying of a roll surface to assist in the prevention in the distortion of its surface. The invention has for its objective to improve such valves and techniques, which objective is met by a method of controlling the provision of coolant along the length of a roll by providing independent control over a number of spray valves strategically located along the length of the roll, each spray valve being separately controlled in accordance with the sensing of a deviation from flatness of the roll or a product rolled by the roll, each spray valve being so structured and controlled to enable it to be selectively switched on and off and when switched on be so controlled as to allow a variation of coolant issued by the spray valve. A valve to serve this purpose comprises a chamber, an outlet (3) from the chamber, a piston (5) slidably located in the chamber (4), at least one fluid inlet to the chamber, said piston cooperating with said at least one fluid inlet to provide a variable degree of opening and/or cooling of the fluid inlet and whereby to provide a variable degree of coolant issuing from the outlet from the chamber.

Description

SPRAY VALVE

This invention relates to spray valves and is particularly, but not necessarily exclusively,

concerned with spray valves for the direction of coolant against the rolls employed in the cold

rolling of plate, strip or foil in both ferrous and non-ferrous materials.

There are many applications where it is essential to have a flat rolled product, with the attendant need to monitor and analyse the rolled surface of the plate, strip or foil, and to provide a means to attempt to correct any deviations as they are detected.

Deviations in flatness in rolled products are caused by a combination of different factors,

but a principal cause is the creation of so-called crowned rolls, a circumstance where the rolls

are thermally deformed to provide a convex roll surface that over-roll the flat product at its centre, or the creation of concavely deformed rolls that indent the edges of the flat product during rolling. These symmetrical thermal deviations of the roll barrel can be controlled by roll bending and roll shifting etc. However, for control of the asymmetrical diametral thermal expansions of the roll surface, which are the cause of non-uniform reductions across the width

of the strip, precise and metered cooling of the rolls is vital if flatness and dimensional accuracy

of the product are to be attained.

These two conditions in rolls can be combatted by providing a means of supplying coolant along the length of the rolls. Thus, it is known to divide the length of the rolls into zones or bands of uniform width, which width conforms to the target width of a flatness meter. Separate

coolant supply means are provided for each zone and activated by the output from the flatness

meter and such that different degrees of coolant can be provided to different zones of the rolls

in accordance with the readings taken by the number of flatness meters provided.

The coolant supply means are each provided with a respective spray valve. Spray valves

as are currently available are on/off valves. Any requirement for a variation in the quantity of coolant supplied to a particular roll zone must then be accomplished by either having a bank of valves each providing different flow rates, or by pulsing an on/off valve for different lengths of time. Neither control means is particularly efficient in its provision of required cooling at a

particular point on a roll. The object of the present invention is to provide a spray valve that overcomes those

disadvantages mentioned above.

According to the present invention, a method of controlling the provision of coolant along the length of a roll comprises providing independent control over a number of spray valves strategically located along the length of the roll, each spray valve being separately controlled in accordance with the sensing of a deviation from flatness of the roll or a product rolled by the roll, each spray valve being so structured and controlled as to enable it to be selectively switched on and off and when switched on be so controlled as to allow a variation of coolant issued by that spray valve.

According to a second aspect of the present invention, a spray valve comprises a chamber, an outlet from the chamber, a piston slidably located in the chamber, at least one fluid

inlet to the chamber, said piston co-operating with said at least one fluid inlet to provide a

variable degree of opening and/or closing of the fluid inlet, and whereby to provide a variable degree of coolant issuing from the outlet from the chamber.

Preferably, the spray valve is so structured and controlled whereby when switched on the

issue of coolant may be infinitely variably controlled.

To achieve a variable degree of opening or closing of the valve, a fluid reservoir may be

provided surrounding the chamber with a number of linearly spaced connections as between the

fluid reservoir and the chamber to be successively opened and/or closed by a movement of the

piston along the chamber. However, and more preferably, an infinitely variable degree of opening or closing is provided by providing a frusto-conical or domed end to the piston of closest approach to the outlet from the chamber and a correspondingly shaped sector in the chamber Such a construction can be employed in place of or in conjunction with a number of aligned

connections as between the reservoir and the chamber Thus, as the piston is moved across the

openings in the wall of the chamber, the co-operation between the shaped end of the piston and the said sector of the chamber provides an infinitely variable supply of fluid from the reservoir to the chamber and hence to the outlet from the chamber

To provide the correct pattern of spray from the valve, the outlet from the chamber may be provided with an appropriate jet nozzle, such as a flat jet nozzle In common with known practice, the length of a roll can be zoned and a number of

flatness meters provided, one for each zone, each flatness meter being either directly connected to a co-operating spray nozzle, or each of the flatness meters can be connected to an appropriate microprocessor which in turn is connected to the spray valves and whereby during the rolling operation the instant any deviation from flatness of the roll surface is sensed, from the product or perhaps a scanning of the roll itself, an immediate signal can be sent to one or more of the

spray valves to provide a spray of coolant, to remove a spray of coolant, or to vary the supply

of coolant as may be required during the rolling process

The spray valve is preferably provided with a stepping motor the shaft of which may be

externally screw-threaded and engages a threaded bore in the piston Alternatively the piston is

provided with a threaded stem passing through a bearing at the remote end of the chamber to a

coupling to the shaft of the stepper motor Thus, a rotation of the stepper motor and hence a

rotation of its shaft, is translated into a linear movement of the piston to a degree determined by

the degree of rotation of the stepper motor With the stepper motor of each valve suitably

connected to the respective flatness meter, or to a microprocessor which receives signals from all of the flatness meters, the stepper motor can be driven to any required degree, forward or reverse, to provide any linear movement required of the piston to close and open the valve and

to infinitely vary the degree to which the valve is open, as is required during the rolling process

One example of the invention is illustrated in the accompanying drawing, which is a

schematic side elevation of a spray valve in accordance with the invention

In the drawings a spray valve 1 has a body 2 with an outlet 3 from a chamber 4 having a piston 5. Around the chamber 4 is a reservoir 6 for coolant with a number of connections 7 to

the chamber 4 Secured to the outlet 3 is a flat jet nozzle 8 held in place by an encapsulating nut

9 fitted to the body 2

To the opposite side of the piston 5 to the outlet 3, it is provided with a feathered stem

10 that extends through a bearing 1 1 to a coupling 12 connecting the threaded stem to a stepper

motor 13 located in a motor chamber 14 to the rear of the body 2 In the wall of the chamber

4 surrounding the piston 5, there is a projection 15 locating in a groove 16 in the wall of the piston, to hold the piston against rotation during a forward and a reverse movement To its front end, the piston has a rounded nose 17 to co-operate with a frusto-conical sector 18 of the

chamber 4 leading to its outlet

The connections 7 from the reservoir 6 to the chamber 4 may be symmetrically disposed,

or may be differently angularly set to space the intersections between the connections 7 and the chamber 4 along the length of the chamber

Passageways 19 are provided interconnecting the reservoir 6 with the chamber 4

rearwardly of the piston 5 whereby to equalise water pressure in front of and behind the piston,

and to act as a damper to inhibit any vibratory movement of the piston To ensure that coolant

does not reach the stepper motor, a drain 20 is provided between the chamber 4 behind the piston

5 and the stepper motor chamber 14, any coolant leaking past the coupling bearing 1 1 draining out of the valve.

In use a number of spray valves 1 are strategically positioned along the length of a roll (not shown) and connected to a respective and cooperating flatness meter that may be connected directly to the stepper motor of its valve or may be connected via a micro-processor during cold

rolling and during which there is an inevitable heating effect due to friction between the roll and the plate strip or foil the flatness meter senses any deviation from flat of the rolled surface or of the roll within the target width of a particular flatness meter. The reading from the flatness meter is passed to the stepper motor possibly through the intermediary of a micro-processor to cause a substantially instantaneous drive (forward or reverse) of the stepper motor to adjust the position of the piston 5 within the chamber 4 first to control the release of coolant from the reservoir 6 to the chamber 4 by uncovering intersections between the connections 7 and the chamber 4 to a greater or to a lesser degree, and to position the nose 17 in relation to the frusto-conical sector 18 of the chamber 4 to provide an infinitely variable control over coolant reaching the nozzle 8.

Claims

1 A method of controlling the provision of coolant along the length of a roll

characterized by providing independent control over a number of spray valves strategically located along the length of the roll, each spray valve being separately controlled in accordance with the sensing of a deviation from flatness of the roll or a product rolled by the roll, each spray

valve being so structured and controlled as to enable it to be selectively switched on and off and when switched on be so controlled as to allow a variation of coolant issued by that spray valve.

2. A spray valve characterized by a chamber (4), an outlet (3) from the chamber, a piston (5) slidably located in the chamber, at least one fluid inlet (7) to the chamber, said piston

co-operating with said at least one fluid inlet to provide a variable degree of opening and/or closing of the fluid inlet, and whereby to provide a variable degree of coolant issuing from the outlet (3) from the chamber (4).

3. A spray valve as in Claim 2, characterized in that it is so structured and controlled whereby when switched on the issue of coolant is infinitely variably controlled.

4. A spray valve as in Claim 2, characterized in that to achieve a variable degree of

opening or closing of the valve, a fluid reservoir (6) is provided surrounding the chamber (4)

with a number of linearly spaced connections (7) as between the fluid reservoir (6) and the chamber (4) to be successively opened and/or closed by a movement of the piston (5) along the chamber.

5. A spray valve as in any one of Claims 2 to 4 characterized in that to provide an

infinitely variable degree of opening or closing of the valve (1 ), there is provided a frusto-conical

or domed end (17) to the piston (5) of closest approach to the outlet from the chamber and a

correspondingly shaped sector ( 18) in the chamber.

6. A spray valve as in any of Claims 2 to 6, characterized in that a jet nozzle (8) is provided on the outlet (3) of the chamber (4)

7 A spray valve as in any of Claims 2 to 6 characterized in that there is provided a

stepping motor (13) the shaft of which is externally screw-threaded and engages a threaded bore

in the piston. 8 A spray valve as in any of Claims 2 to 6, characterized in that the piston is provided

with a threaded stem ( 10) passing through a bearing ( 1 1 ) at the remote end of the chamber (4) to a coupling (12) to the shaft of the stepper motor ( 13)

9 A spray valve as in any of Claims 2 to 8, characterized in that the chamber (4) behind the piston (5) is connected to the reservoir (6) to provide a balanced coolant pressure to both

sides of the piston.

10 A spray valve as in any of Claims 2 to 9 characterized in that a drain (20) is provided between the chamber (4) behind the piston (5) and the stepper motor chamber ( 14) to ensure that coolant cannot reach the stepper motor