| EP0631075A1 | 1994-12-28 |
| 1. | An electromagnetic valve device to be used for control ling a fluid flow, with the aim of controlling/regulating pa rameters connected to inherent properties such as pressure and temperature, comprising a mainly sleeveshaped valve housing (1) with a through fluid flow passage and formed partly for mounting into a pipe line, channel or similar pas sage where fluid is flowing, partly for connection to a hous ing (7) for the electromagnet (5,6), the valve housing (1) being provided with a preferably plate/discshaped seat plate (2) with at least a through flow opening (2a), with which cooperates an outer displaceable valve body (12) incor porated in the valve, which also comprises an inner displace able valve body (13) arranged to influence the valve's degree of opening to flow, character i z e d i n that in a first end position with its active portion (12') bearing on the seat plate (2), said outer valve body (12) is shaped and sized to overlap and cover the flow opening (2a) of the seat plate (2), said active abutment portion (12') of the outer valve body (12) having at least one through flow opening (12a) with a smaller opening area than the flow opening (2a) of the seat plate (2) and, in the overlapping and covering end position of said active abutment portion, positioned within the defining edge of the flow opening (2a) of the seat plate (2), and that in its two end positions said inner dis placeable valve body (13) closes and exposes, respectively, the flow opening (12a) of the outer valve body (12). |
| 2. | A device according to claim 1, c h a r a c t e r i z e d i n that the electromagnet housing (7) which is formed to accommodate the magnet coil (6) and the anchor (15) and parts of said valve bodies (12,13), their guides etc., is formed to be sealingly (11) connected, possibly through intermediate sockets (4), to a branch socket projecting laterally from the sleeveshaped valve housing (1), and that the longitudinal axis of the valve housing (1) forms an acute angle to a com mon axis of symmetry (3) of the electromagnet housing (7), magnet coil (6) and anchor (15) and valve bodies (12,13) and seat plate (2). |
| 3. | A device according to one or more of the preceding claims, c h a r a c t e r i z e d i n that the outer valve body (12) is sleeveshaped and provided with at least one ap ertured (12a) gable plate (12') which forms said active abut ment portion, which is to bear, in one end position, on the opposite face of the seat plate (2) round the flow opening (2a) thereof, and that the outer sleeveshaped valve body (12) has at least one further opening (12b) which forms a pressureequalizing hole into its internal cavity. |
| 4. | A device according to one or more of the preceding claims, c h a r a c t e r i z e d i n that said inner dis placeable valve body (13) is arranged concentrically within the outer sleeveshaped valve body (12) with relative dis placeability thereto, along said common axis of symmetry (3), said inner displaceable valve body (13) having at its end nearest to the seat plate (2) a tapered configuration forming a bevel/conical edge (13") relative to the end surface (13') which is essentially perpendicular to the common axis of sym metry (3). |
| 5. | A device according to one or more of the preceding claims, character i z e d i n that said inner valve body (13) is connected to the anchor (15) of the electro magnet (6,15) through an intermediate connector (13"'), these three parts extending coaxially, referring to said axis of symmetry (3), said anchor (15) in the form of an elongate straight body being guided in a stationary guiding sleeve (5) with a closed end. |
| 6. | A device according to one or more of the preceding claims, c h a r a c t e r i z e d i n that the outer valve body and anchor assembly (1315) carries a transversal damp ing disc (14) which encircles and is displaceable relative to the connector (13"'), essentially following the linear dis placing motion of the assembly (1315) along the axis of sym metry (3) inside the side branch socket/damping chamber (1"') of the valve housing (1) and/or in the internal cavity of the annular/cupshaped intermediate lid (4) mounted between that and the electromagnet housing, said damping disc (14) moving in fluid, in operation, as the fluid is flowing through the valve housing (1), filling the internal cavity defined by the internal walls of the valve housing (1), lid (4) and guide sleeve (5). |
| 7. | A device according to one or more of the preceding claims, c h a r a c t e r i z e d i n that the anchor (15) is formed with a draining groove (15"). |
| 8. | A device according to one or more of the preceding claims, c h a r a c t e r i z e d i n that in its end por tion the most distant from the free outer end of the anchor (15), the draining groove (15") is formed with a reduced depth. |
| 9. | A device according to one or more of the preceding claims, character i z e d i n that between the damping disc (14) and an opposite annular surface inside the assembled housing assembly at the lid 4 a pressure spring (16) is arranged. |
| 10. | A device according to one or more of the preceding claims, c h a r a c t e r i z e d i n that said further opening or openings (12b) of the outer sleeveshaped valve body (12) is/are located in the side wall (12") of the valve body (12) near its axial ends, which each have a gable plate/lid (12', 12"') arranged thereto, and that the lid (12"') with the longest distance to the seat plate (2) has a central passage (12c) for the connector (13"') between the valve body (13) and the anchor (15). |
In many industrial processes and in ventilation plants in general, adjustable choke valves are used to control a fluid flow, with the purpose of controlling physical parameters such as temperature, pressure and acidity (pH) in the system downstream. Such adjustable choke valves are normally driven by an electromotor with associated gears, or a hydraulic ac- tuator. Both types of driving elements are expensive, and also require relatively complicated and expensive control equipment in order to deliver the necessary impulses to the electromotors or the hydraulic actuators in order to adjust the degree of opening of the valve. By low pressures and small dimensions it is also possible to utilize directly con- trolled electromagnetic valves. Norwegian patent N0172410 discloses a valve which is capable of opening to, and shut- ting off, a fluid flow also by somewhat higher pressures,
without causing knocking in the pipes, to which it is con- nected, when closing.
The perhaps most used method of controlling an amount of fluid for a period of time, is to use an adjustable choke valve, in which the valve provides a desired flow rate by be- ing adjusted to a position between closed and fully opened.
Another method is pulse width modulation, whereby the control valve adopts either a fully closed or fully opened position.
In the latter method the amount of flowing fluid is deter- mined by for how much of the total time the valve is in its open position. Conventionally, the adjustable choke valve method has been applied in continuous processes, for example in temperature adjustment by means of flowing warm, alterna- tively cold, liquid, whereas the on/off-method has found its use within discontinuous processes, for example in the fill- ing of a vessel. However, there is a certain overlapping.
The object of the invention is to remedy the negative as- pects, for example high procurement costs, of known tech- nique.
The object is realized according to the invention through the features specified in the description below and the subse- quent Claims.
What is new about the invention, is that a simple and thereby inexpensive electromagnetic on/off-valve, in the connection in question being arranged to work with large flows of fluid, can be controlled between a closed and fully opened position at such a high rate that the resulting fluid flow through the valve has the character of being controlled by an adjustable choke valve. For several reasons, e. g. overheating, such a
control cannot be used in valves of a known embodiment. The magnetic valve comprises, in addition to a conventional hous- ing, a valve part which is arranged to be able to work fast, with a soft opening and closing characteristic, in addition to being able to open up a large flow area against a rela- tively high differential pressure by a considerably lower opening force as compared to known technique. Further the an- chor of the electromagnet is provided with a choked drain groove in order to damp the valve further before its abutment in the fully opened position.
In the following, two non-limiting examples of preferred em- bodiments are described and visualized in the accompanying drawings, in which: Fig. 1 is a sectional view of an on/off-valve in its closed position; Fig. 2 is a sectional view of an on/off-valve in its par- tially open position; Fig. 3 is a sectional view of an on/off-valve in its fully opened position; Fig. 4 is a sectional view of a control valve in its closed position; Fig. 5 is a sectional view of a control valve in its fully opened position.
In the figures the reference numeral 1 identifies a valve housing with two connection sockets 1'and 1"for the inlet
and outlet of fluid. An arrow in the drawings indicates the direction of flow through the connection sockets 1'and 1". A seat plate 2 with a through opening 2a is fast with the hous- ing 1. The centre line of the opening 2a is concentric with the valve axis 3. Following terms like axial and radial al- ways refer to the valve axis 3. A lid 4 formed like an in- verse cup is attached to the housing 1 and provided with a tight guide sleeve 5 which projects above the lid 4 and into a magnet coil 6. The magnet coil 6 is positioned concentri- cally about the guide sleeve 5 in a coil housing 7 with asso- ciated connection box 8. The connection box 8, the coil hous- ing 7 and the magnet coil 6 are secured to the lid 4 by sev-, eral screws 9 and an associated spacer 10, which is also ar- ranged to cool the magnet coil 6 located within. A seal 11 seals between the housing 1 and the lid 4. The internal bore of the lid 4 and part-of the adjacent cavity of the valve housing 1 form a damping chamber 4'.
The valve is provided with an outer cylindrical valve body 12 and an inner cylindrical valve body 13. The outer valve body 12 is formed as a hollow body, in which a radial gable plate 12'is arranged to bear in a sealing manner on the seat plate 2 when the valve is in its closed position, covering the opening 2a at the same time. The gable plate 12'is provided with a centric opening 12a therethrough, whose function will be explained below. A cylindrical side wall 12"is provided with one or more through openings 12b, which are arranged to provide pressure equalization internally in the outer valve body 12. A lid 12"'with a through centre opening 12c is at- tached, for example by screwing, to the cylindrical side wall 12". A lower end surface 13'of the inner valve body 13 is arranged to bear sealingly on the gable plate 12'when the valve is in its closed position, while covering the opening
12a at the same time. At its lower end portion the inner valve body 13 is provided with a chamfer/bevel edge 13", whose function will be described below, and at its opposite end portion it is provided with a fixedly connected connector 13"'. The connector 13"'is taken through the opening 12c and secured to an anchor 15 through a screwing 15'. A damping disc 14, whose function will be described below, is posi- tioned concentrically round the connector 13"'. The anchor 15 is provided with a draining groove 15", which is formed with a reduced depth in its lower portion 15"', thereby being ar- ranged to choke the fluid flow through the groove 15"against the internal wall of the guide sleeve 5 just before the an- chor 15 reaches its upper end position.
In operation the housing 1, lid 4 and guide sleeve 5 are filled with fluid. The fluid is supplied through the connec- tion socket 1'by pressure provided from, for example, a pump, not shown. By closed valve a pressure difference across the seat plate 2 occurs because the valve bodies 12 and 13 shut off flow through the openings 2a and 12a. A force, clos- ing force, equalling the pressure difference across the valve, multiplied by the area of the opening 2a, forces the valves 12 and 13 in the direction towards the seat plate 2.
The portion of the force which acts on the inner valve body 13, is equal to the pressure difference across the valve mul- tiplied by the area of the opening 12a. The ratio of the closing force acting on the inner body 13 and the total clos- ing force acting on the valve bodies 12 and 13, is determined by the ratio of the areas of the openings 2a and 12a. In a preferred embodiment the diameter of the opening 12a is in the order of one fourth of the diameter of the opening 2a.
Thus a considerably smaller force is required to open only the valve body 13 than to open the valve bodies 12 and 13 to-
gether. In addition to the differential pressure forces the specific gravities of the valve bodies 12 and 13 and anchor 15 also act on the valve bodies 12 and 13.
The opening of the valve is carried out in two steps. An electric voltage is connected to the magnet coil 6. The mag- netic forces generated, see Fig. 2, are sufficient for lift- ing the inner valve body 13 up from the gable plate 12', thereby opening to fluid flow through the opening 12a. The damping disc 14 is arranged to be displaced freely along the connector 13"'and is thus not moved in this phase of the opening. Fluid enters below the inner valve body 13 and the chamfer 13". The angle of the chamfer 13"relative to the end surface 13'causes a pressure increase to take place in the fluid below the chamfer 13", which contributes to lifting the inner valve body 13 further up from the gable plate 12'. The inner valve body 13 is displaced internally in the outer valve body 12 until it abuts the lid 12"'. By the fact that the fluid is flowing through the opening 12a, the differen- tial pressure between the two faces of the seat plate 2 is reduced, and the power from the magnet coil 6 will be suffi- cient to lift also the outer valve body 12 up from the seat plate 2. See Fig. 3. Thereby the opening 2a is uncovered and fluid may flow through. During this part of the opening phase, the damping disc 14, which is bearing on the lid 12"', is displaced through the surrounding fluid and damps the opening speed, in that fluid has to flow through the annular gap formed between the outer edge of the damping disc 14 and the damping chamber 1"', 4'. The fluid inside the guide sleeve 5 is displaced through the draining groove 15"when the anchor 15 is displaced into the guide sleeve 5. The depth of the draining groove 15"is gradually reduced to nil at the lower portion 15"'of the anchor 15, so that immediately be-
fore the anchor 15 reaches its end position, wherein the valve is in its fully opened position, the fluid flow is shut off by the internal tubular surface of the guide sleeve 5 covering the entire draining groove 15". This configuration is arranged to damp the speed of motion of the anchor 15, and thereby the valve bodies 12 and 13 when they reach their end positions in the fully opened position.
In the open position the outer valve body 12 and the damping disc 14 rest on the inner valve body 13. As the magnet coil now loses its voltage, the anchor 15 is displaced together with the valve bodies 12 and 13 down to the gable plate 12' of the outer valve body 12, meets the seat plate 2 and thereby closes the opening 2a. In the first phase of this movement the damping disc 14 is lagging behind in the sur- rounding fluid until it abuts the anchor 15 which is on its way downwards. The damping disc 14 then damps the closing speed in the same manner as in the opening of the valve, as has been described above. Fluid may still flow through the opening 12a and thereby prevents pressure knocking in the ad- jacent pipe system in this stage of the closing. The inner valve body 13 is then displaced in the outer valve body 12 until the end surface 13'meets the gable plate 12', thereby closing the opening 12a. By the fact that in this last clos- ing phase, in the same manner as during the opening of the valve, the fluid flow past the chamfer 13"supplies an upward axial force to the inner valve body, the closing speed in this last phase is gradually reduced, whereby pressure knock- ing is prevented also in this closing phase.
In another embodiment, see Figs. 4 and 5, the valve is pro- vided with a pressure spring 16. The spring 16 acts against the damping disc 14 with a force depending on the degree of
compression of the spring 16. In this embodiment the valve is arranged to adopt, by controlling the effect of the magnet coil 6 and thereby the magnetic field acting on the anchor 15, any position between the fully closed and fully opened positions. In addition to damping the opening and closing speed, the damping disc 14 is arranged in this embodiment also to damp variations so that the fluid flow through the valve will be as even as possible. The area of the annular gap which is formed between the outer edge of the damping disc 14 and the damping chamber 1"', 4'can be adapted to the viscosity of the liquid in order to provide the best possible damping.
The valve according to the invention enables a considerable cost reduction in the installation and operation of a plant, in which conventional adjustable throttle valves would other- wise have to be used.