A VALVE

INTRODUCTION

The present invention relates to a valve comprising a body part forming:

- an inlet,

- an outlet,

- a valve seat located in a flow path between the inlet and outlet,

- a high pressure chamber between the inlet and the valve seat and a low pressure chamber between the outlet and the valve seat,

- a low flow valve seat located in a low flow chamber between an upstream low flow passage extending between the high pressure chamber and the low flow chamber and a downstream low flow passage extending between the low flow chamber and the low pressure chamber, and

- a pilot valve seat located in a pilot chamber between a downstream pilot passage extending between the low pressure chamber and the pilot chamber and an upstream pilot passage extending between the pilot chamber and a control chamber.

The valve is operable as a servo valve e.g. for controlling a flow of petrol.

BACKGROUND OF THE INVENTION

Valves with a main flow passage and a low flow passage are known. As an example, petrol pumps at gas stations normally have a valve with a main flow passage which is servo operated and which provides a relatively large flow rate for fast pumping. The main valve member is moved via a differential pressure between pressures on opposite sides of the main valve member, and to control the differential pressure, a pilot valve member which is small relative to the main valve member is opened and closed to lower or raise the pressure on one side of the main valve member. Due to its relatively small size, movement of the pilot valve member requires less force, and the pilot valve member may e.g. be operated via a solenoid. To enable measuring of a precise quantum, the valve further comprises a low flow passage which can be opened and closed by a low flow valve member of a relatively small size. The low flow passage bypasses petrol across the main valve member and can be operated e.g. by a solenoid.

Since the valve incorporates not less than three valve members which are located in individual chambers interconnected by a plurality of passages, inlet openings, outlet openings, valve seats etc, manufacturing of such valves is relatively complicated and normally, the valves are typically made from at least two separate house components where each component comprises at least one valve member. The house components form openings towards the other house components to enable exchange of petrol between the components.

The fact that the components must be assembled typically complicates the layout of the valve, and the required interface surfaces with connectivity of the relatively large number of passages between each house component typically restricts the number of alternative locations for the passages,

chambers, and valve members in the house components. Often, passages are drilled from an outer surface into the house component in which the passage joins with other passages or chambers, and the opening is subsequently closed by a closing member welded into the house component or the opening may join an opening of an adjacent house component. The large number of such openings and/or sealed openings into the valve is undesired with respect to the reliability and tightness of the valve, and inevitably, the manufacturing of separate components and the subsequent assembly thereof complicates the process and constitutes a potential risk of leakage. JP10-132132 discloses a valve of this type. In general, the assembly of the separate house components also requires accurate positioning of each passage opening in the outer surface of each component, and normally, it a sealing member, e.g. an O-ring, is required to seal the abutting surfaces of adjacent house components.

DESCRIPTION OF THE INVENTION

It is objects of the invention to improve manufacturing and reliability of the existing valves. This object is accomplished by a valve wherein each passage section is worked from respective chambers into the body part. I.e. all passage sections are workable by a tool which can form the passage section by movement in an axial direction from a chamber into the body part, e.g. by drilling or milling. I.e. all openings which are made in the housing are functional openings which are made to provide access from a chamber into a passage, and no openings are made merely for getting access to an inner portion of the body part for making a passage therein. According to the invention, all passages are preferably visible only on inner surfaces of the chambers and nowhere else. Accordingly, all passages are sealed towards the ambience when the chambers are closed, and no individual sealing of passages on the outer surface has to

be made. This reduces the risk of leakage and enables reduced manufacturing costs.

The valve seat forms seat for a main valve member which moves between an open position wherein the high pressure and low pressure chambers are in fluid communication and a closed position wherein the main valve member contacts the valve seat and prevents fluid communication between the high pressure and low pressure chambers. The control chamber is located above the valve seat, so that the valve member can separate the control chamber from the low and high pressure chambers, and so that the main valve member is movable by a pressure difference between pressure in the high pressure chamber, pressure in the low pressure chamber, and pressure in the control chamber,

Each passage section may have any cross sectional shape, e.g. a circular or quadrangular cross sectional shape, but preferably with one or more even sidewall(s) which extend(s) axially from a chamber and into the body part. An even sidewall has either no variation in its cross sectional shape and size throughout the axial length of the passage section or it varies continuously without any steps, i.e. the wall extends either parallel to an axially extending centre axis of the passage section or the wall extends evenly inclined or declined with respect to the centre axis. Such a passage section may preferably be machined by drilling or milling from a surface of one of the chambers and into the body part.

In one embodiment of the invention, at least one of the passages comprises a passage section which is drilled from one chamber into the body part and which joins with another passage section which is drilled from another chamber into the body part.

Preferably, each passage section comprises one open end into one of the chambers and an axially opposite open end into another one of the chambers or into another passage section.

To enable return of the main valve member upon closing the pilot passage, the valve may further comprise a pressure equalisation structure which provides a flow between the high pressure chamber and the control chamber. In one embodiment of the invention, the equalisation structure forms a constantly open passage between the high pressure chamber and the control chamber. To facilitate a pressure drop in the control chamber when the pilot valve member is moved to the open position, the pressure equalisation structure may provide a larger flow resistance than the upstream and downstream pilot passages in combination. When the. pilot valve is open, flow will thereby flow from the control chamber to the low pressure chamber at a flow rate which is larger than the flow rate of the flow in the equalisation structure which flows from the high pressure chamber to the control chamber. As a result, the pressure in the control chamber drops. The equalisation structure may e.g. comprise the upstream pilot passage in combination with an equalisation passage extending from the high pressure chamber to the pilot chamber. To enable a drop of pressure in the control chamber when the pilot passage is opened, the equalisation passage may e.g. exert a larger flow resistance than the upstream pilot passage. When the pilot passage is opened, the resulting pressure will become a pressure which is between the pressure of the low pressure chamber and the high pressure chamber, and when the pilot passage closes, the equalisation structure will at least essentially equalise the pressure in the control chamber with the pressure in the high pressure chamber. The valve may further comprise a spring biasing the valve member towards the closed position.

In one embodiment of the invention, the body part is in one piece. As an example, the body part may be made by starting out with one single work piece and by reshaping it, e.g. by removing material in a cutting process or by reshaping it by a pressure which exceeds the yield point of the material, e.g. by hammering out, forging, casting or any similar process wherein a single work piece changes shape without being joined to other work pieces. The one piece body part may preferably exclusively have one single main opening into the control chamber, a pilot opening into the pilot chamber, a low flow opening into the low flow chamber, an opening forming the inlet, and an opening forming the outlet, and no other openings. In particular, it is an object of the invention not to provide any openings in the body part except from those which serves a functional purpose with respect to the operation of the valve.

The main opening may e.g. be formed in an upper surface of the body part, and the pilot opening and low flow opening may be formed in a lower surface on an opposite side of the body part. From the opening, the chambers extend along respective axes into the body part. The chambers may e.g. be rotationally symmetric around the respective axes or they may at least comprise a symmetric basic shape from which shape unsymmetrical supplementary shapes may be formed. I.e. the chambers could be made by drilling or milling a cylindrical cavity into the body part, and by further drilling or milling junction cavities into the cylindrical sidewall, e.g. for connecting the chamber with one of the passages.

In addition to the body part, the valve may further comprise a main valve member being movable between an open position wherein the high pressure and low pressure chambers are in fluid communication and a closed position wherein the valve member contacts the valve seat and prevents fluid communication between the high pressure and low pressure chambers, the valve member being movable by a pressure difference

between pressure in the high pressure chamber, pressure in the low pressure chamber and pressure in a control chamber.

The valve may further comprise a low flow valve member being movable between an open position wherein the upstream and downstream low flow passages are in fluid communication and a closed position wherein the low flow valve member contacts the low flow valve seat and prevents fluid communication between the upstream and downstream low flow passages.

The valve may further comprise a pilot valve member being movable between an open position wherein the upstream and downstream pilot passages are in fluid communication and a closed position wherein the pilot valve member contacts the pilot valve seat and prevents fluid communication between the upstream and downstream pilot passages.

The main opening could be closed by a main closure which forms a guide for guiding the main valve member between the open position where the high pressure chamber is in direct fluid communication with the low pressure chamber across the valve seat. The main closure could be releasably attached to the body part to enable service in the main chamber, e.g. in connection with replacement of the main valve member. As an example, the closure could be attached by bolts, and a gasket could be arranged the body part and the closure to improve the tightness. The closure could also be unreleasably attached by curling an edge portion of one of the body part and the closure into contact with an edge of the other one of the body part and the closure.

In one embodiment, the main valve member moves in close contact with an inner surface of a tubular sleeve which is located in the main chamber. In this case, the walls of the control chamber are formed by an upper surface of the main valve member, an inner surface of the sleeve and a

lower surface of the closure. The body part could be made of metal and the sleeve and main valve member could be made from a synthetic material, e.g. from a polymer. The sleeve may, in a top end, abut the main closure, and between the main closure and the sleeve, a path could be established which allows a fluid flow out of the control chamber and thereby allow access from the control chamber to the upstream pilot passage and equalisation passage. The path could be formed as a depression or notch in one or both of the inner surface of the closure and upper edge of the sleeve. The arrangement of the sleeve and closure which in combination forms a flow path out of the control chamber may also be considered independently from any other features of the valve described until now.

Correspondingly, the low flow opening and pilot opening may be closed by closing means forming a plunger tube in which a plunger moves to operate the corresponding valve members - the plunger is sometimes referred to as an armature. The plunger tubes may have a threaded portion which is screwed into a corresponding threaded portion of the chambers, or the plunger tubes may have a flange which abuts a corresponding flange of the chambers and which are fixed thereto, e.g. by use of a screwed cap, a pipe union shaped nut or the like, or the tubes may be welded into sealing contact with the chamber wall. If the main valve member moves in a first direction towards its closed position and the other valve members moves in an opposite, second, direction towards their closed positions, i.e. so that the main chamber extends from within the body part and outwardly towards an opening in a surface which is on an opposite side of the body part relative to the openings into the other chambers, service is facilitated since the main chamber can be opened without having to open any of the other chambers.

In a second aspect, the invention provides a method of making a valve of the above-described kind. In particular, the method comprises the step of forming each passage by axial movement of a tool such as a drill from one of the chambers and into the body part without making any openings into the body part except from the openings in the chambers through which the passages are made.

DETAILED DESCRIPTION

In the following, a preferred embodiment of the invention will be described in further details with reference to the drawing in which:

Fig. 1 shows a perspective view of a body part seen from above,

Fig. 2 shows a cross sectional view of the body part,

Fig. 3 shows a cross sectional view of a valve according to the invention,

Fig. 4 shows a perspective view of a body part seen from below the valve,

Fig. 5 shows a view of the body seen from below with indication of section A-A, c.f. Fig. 8 and indication of section C-C, c.f. Fig. 9,

Fig. 6 shows a view of the body seen from a front of the valve,

Fig. 7 shows a view of the body seen from the side with indication of section G-G, c.f. Fig. 10,

Fig. 8 shows section A-A, c.f. Fig. 5,

Fig. 9 shows section C-C, c.f. Fig. 5,

Fig. 10 shows section G-G, c.f. Fig. 7, and

Fig. 11 shows a perspective view of a closure for the main opening,

Fig. 12 shows a perspective view of valve with the closure attached thereto,

Fig. 13 shows a perspective view of the valve including plunger tubes, and

Fig. 14 shows a perspective view of the valve including a solenoid.

As shown in Figs. 1 and 2 the valve body part 1 forms an inlet 2, an outlet 3, a valve seat 4 located in a flow path between the inlet and outlet. Between the inlet and the valve seat, the flow path forms a high pressure chamber 5, and between the outlet and the valve seat, the flow path forms a low pressure chamber 6. The valve seat is closed by a main valve member 7, c.f. Fig. 3 showing a cross sectional view wherein a valve member is located to prevent passage between the low pressure and high pressure chambers 6, 5. Above the main valve member 7, the body forms a control chamber 8. The valve member 7 is moved under influence of a pressure difference between pressure of the low pressure chamber, the high pressure chamber 5 and the control chamber 8, and under influence of the closing force from the spring 9 which bias the valve member against the closed position shown in Fig. 3. The body part forms a main opening 10 in an upper face 11 of the body part 1. The main opening opens into the control chamber and valve member.

As shown in Fig. 4 the body further forms a low flow opening 12 into a low flow chamber 13, and a pilot opening 14 into a pilot chamber 15. The low flow opening and pilot opening are formed in a lower surface 16 on an opposite side of the body part relative to the upper face 11 in which the main opening is formed.

Fig. 5 shows a view of the body seen from below with indication of section A-A, c.f. Fig. 8 and indication of section C-C, c.f. Fig. 9, Fig. 6 shows a view of the body seen from front, i.e. a view corresponding to Fig. 5 rotated 90 degrees around an axis extending horizontally in the plane of the drawing and located below Fig 5, i.e. in accordance with European rules for drawing. Fig. 7 shows a view of the body seen from the side with indication of section G-G, c.f. Fig. 10, i.e. a view corresponding to Fig. 6 rotated 90 degrees around an axis extending vertically in the plane of the drawing and located to the left of Fig 6.

Fig. 8, i.e. section A-A in Fig. 5, shows a cross sectional views of the valve in which a low flow valve seat 17 and a pilot valve seat 18 is shown in the low flow chamber 13 and pilot chamber 15. In the finished valve, a low flow valve member and a pilot flow member are movably arranged to control flow across the low flow valve seat and the pilot valve seat. Fig. 8 further shows a downstream low flow passage 19 extending between the low flow chamber 13 and the low pressure chamber 6. Fig. 8 further shows a first passage section of a downstream pilot passage 20 extending between the low pressure chamber 6 and the pilot chamber 15. The first passage section is drilled from the pilot chamber 15 into the body part and joins with a second passage section to continue into the low pressure chamber, c.f. Fig. 10, i.e. in section G-G.

Fig. 9, i.e. section C-C in Fig. 5, shows an upstream low flow passage 21 extending between the high pressure chamber 5 and the low flow chamber 13, and an upstream pilot passage 22 extending between the pilot chamber 15 and the control chamber 8. The upstream pilot passage 22 ends in a notch 23 formed into the sidewall of the control chamber 8. Fig. 9 further shows an equalisation passage 24 extending from the high pressure chamber 5 to the pilot chamber 15. The equalisation passage 24 and the upstream pilot passage 22 in combination forms a pressure

equalisation structure 22, 24, providing a flow between the high pressure chamber and the control chamber. The flow in the equalisation passage 24 is restricted in the upper end 25 adjacent the pilot chamber 15 whereby the flow resistance in the pressure equalisation structure 22, 24 becomes larger than the flow resistance in the downstream pilot passage 20.

Fig. 10, i.e. section G-G in Fig. 5, shows a second passage section of the downstream pilot passage 20 which extends between the low pressure chamber 6 and the pilot chamber 15. The second passage section is drilled from the low pressure chamber into the body part and joins therein with the first passage section, c.f. Fig. 8 which is drilled from the pilot chamber into the body part.

As shown in the above described figures, all passages are worked from the chambers and into the body part and no openings except from the openings in the chambers are made. Accordingly, no additional unwanted work relating to closing of openings in the outer surface of the body part is necessary.

Fig. 11 shows a cross sectional view of a closure 26 for closing the main opening 10. The closure comprises a guiding cavity 27 for guiding the main valve member 7 back and forth between a closed and an open position relative to the valve seat 4. The closure further comprises at least one depression 28 which forms an air passage between the closure and a sleeve which will be described further with reference to Fig. 15.

Fig. 12 shows a perspective view of the valve with the closure attached thereto. The closure is attached by flanging - not shown in Fig. 12, whereby an edge of one of the parts is curled over, an in contact with an edge of the other part. A sealing adhesive or a gasket may be located between the two parts to facilitate the tightness of the valve.

Fig. 13 shows a perspective view of the valve with plunger tubes 29, 30 attached to the pilot opening and low flow opening.

Fig. 14 shows a view corresponding to Fig. 13 but with solenoids 31 located around the plunger tubes 29, 30 to move the pilot valve member and low flow valve member under influence of a magnetic field.

Now referring to Fig. 15, showing an enlarged segment of Fig 3, the main valve member 7 moves in close contact with an inner surface of a tubular sleeve 32 which is inserted into the body part via the main opening 10. The valve member 7 and the sleeve 31 are made from a polymeric material. The control chamber 8 is formed between an upper surface 33 of the valve member 7, the inner surface 34 of the sleeve 32 and a lower surface 35 of the main closure 26. An upper axial end portion 36 of the sleeve abuts the lower surface 35, and a depression 28 in the closure, c.f. Fig. 11 , forms a flow path between the sleeve and the main closure and thereby permits a fluid flow from the control chamber 8 to the upstream pilot passage 22 and equalisation passage 24.