GB2207222A

GB2207222A - Electromagnetic valve

Info

Publication number: GB2207222A
Application number: GB08812470A
Authority: GB
Inventors: Rudiger Eiermann; Franz Grull
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-07-20
Filing date: 1988-05-26
Publication date: 1989-01-25
Also published as: DE3723959A1; IT1226126B; FR2618518A3; IT8821194A0; GB8812470D0; DE3723959C2

Description

2207222 - 1 ELECTROMAGNETIC VALVE The present invention relates to an

electromagnetic valve.

A known electromagnetic valve (DE-PS 32 19 799) is provided for the control of a brine entry from a salt supply container into an ion exchange container for the regeneration of water-softening equipment in a dishwashing machine. The valve comprises a housing which is formed in a single part of plastics material and which has stepshaped portions provided with seals for tight insertion into a housing chamber of the water-softening equipment. In that case, arranged downstream of a first housing portion, which is of small diameter and comprises an inlet pipe with a central entry bore and a valve seat, is a housing portion of intermediate diameter, in the wall of which is disposed the outlet opening, whilst the conically narrowing valve seat projeCts into the interior space thereof. Adjoining is a third housing portion of larger diameter, in which a collar of a guide bush is detentable. An armature forming a valve tappet carries a sealing cone, in particular of rubber, and - when the electromagnet is not excited - the action of a spring on the armature causes the cone to close the passage of the valve seat against the water pressure acting on the valve. The armature cannot drop out because of the superposed valve housing with the valve seat, and the valve forms a completely pre-assembled and testable unit.

Also known is an electromagnetic valve (DE-OS 35 17 783) in which a valve housing and valve seat are integrated in a chamber of a salt supply container or ion exchange container of the water-softening equipment of a dishwashing machine. An electromagnetic valve part with a guide bush, an armature, a sealing cone an d so forth are then 1 i i i i - 2 insertable into the housing. In the case of this valve, too, a compression spring must, when the electromagnet is switched off, serve for closing of the valve against the water pressure acting on the valve. Because the compression spring must be designed to be strong for that reason, a correspondingly strong electromagnet is in turn needed for opening of the valve.

There is a need for an electromagnetic valve which in the nonexcited state is suitable for securely closing an inlet loaded by, for example, a water column of about 500 millimetres and can be opened with relatively small electromagnetic force, and which in the opened state may be able to free a relative large passage cross-section. Such a valve should preferably also make possible a secure sealing of the valve passage after switching-off of the electromagnet with greater production tolerances.

According to the present invention there is provided an electro- magnetic valve comprising a valve housing defining an inlet passage and an outlet passage and provided between the passages with a valve seat having a seating seal, an armature carrying a valve member cooperable with the seal, resilient means acting on the armature to urge the valve member towards the seal, and a coil extending around the armature and effective when energised to displace the armature against the force of the resilient means, the valve member being mounted on a ball head of the armature for pivotal movement relative thereto.

In a preferred embodiment the valve comprises an -armature which is loaded by a compression spring, is displaceable by an (?lectromagnet and is guided in a guide bush which is of plastics material,' is i i i 1; i i i insertable into an electromagnet coil and rests by a flange against the electromagnet coil housing. A collar is formed at the flange and overlapped by a collar of a valve housing, which has an outlet passage in the flow Path behind the valve seat and an inlet passage. A valve tappet with a tappet head for the sealing of the valve passage is provided at the armature, which for the oDening of the valve is displaceable by the electromagnet against the compression spring. The valve seat carries a valve seat seal, and the valve tappet has a spherical head, a head seal being provided on the valve tappet head and the tappet head seal being pendulatably arranged on the valve taopet head. Preferably, the tappet head seal is pushable by a part spherical portion into the valve passage of the valve seat seal and in the closed position lies against the valve seat seal by way of a flange with an annular sealing edge. For preference, the tappet head seal is detented relative to the tappet head.

Expediently, on opening of the valve, the flange of the tappet head seal is raisable by its annular sealing edge one-sidedly from the valve passage for a premature pressure balance and, on further raising of the valve tappet, the flange and its head seal free the valve passage. With advantage, in the closed state the compression spring, assisted by the water column present at the inlet passage, holds the flange of the tappet head seal by its annular sealing edge in sealing contact with the valve seat seal.

In the case of such a valve embodying the invention, when the valve is closed in the rest state with the electromagnet switched off, the compression spring acting on the armature and the valve tappet as well as the water column standing at the inlet passage - 4 press the tappet head seal by its flange or the flange sealing edge against the valve seat or the valve seat seal. When voltage is applied to the coil, the armature is drawn back into the bush against the compression spring. In that case, the encircling sealing edge of flange of the tappet head seal is initially raised only by a small gap from the valve seat or the valve seat seal. The water flowing out through this gap by way of the valve passage to the outlet passage makes possible the complete opening of the valve with little opening force and renders the servo-bores otherwise provided in known valves superfluous. When the electromagnet coil is free of current, then the compression spring, assisted by the water column loading the valve, displaces the armature so that the tappet head seal bears against the valve seat seal. Since, because of-the tolerances and a permissible installation in inclined position, the displacement of the valve tappet is not consistently perpendicular to the valve seat plane oriented at 90' thereto, on closing of the valve there is initially a punctiform contact between the sealing edge of the flange of the tappet head seal and the valve seat seal. Thereafter, the sealing edge bears in line contact against the valve seat seal, while the tappet head seal, by reason of its pendulating arrangement on the tappet head, rolls relative to the valve seat seal.

An embodiment of the present invention will now be more particular ly described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a sectional elevation of an electromagnetic valve embodying the invention, the valve being shown in closed setting; j Fig. 2 is a detail sectional view, to enlarged scale, showing a seal arrangement of the valve in the closed setting; Fig. 3 is a view similar to Fig. 2, but showing the seal arrangement during closing operation of the valve; and Fig. 4 is a view similar to Fig. 3, but showing the seal arrangement in the open setting.

Referring now to the drawings, there is shown an electromagnetic valve comprising an electromagnet 1 with a coil housing 2, connecting tags 3 and a plastics material guide bush 5 inserted into the coil. The bush 5 is inserted into the coil until a flange 6 connected with the bush bears against the coil housing and is fastened to the electromagnet 1 through, for example, stampable detent lugs or the like of the base 8 of the bush. The bush 5 serves for the reception of a compression spring 9, and an armature 10, which is sheathed by plastics material, is displaceable by the electromagnet and carries a valve tappet 11.

The valve tappet 11 ends in a spherical tappet head 7 on which a tappet head seal 4 of plastics material or rubber is provided. The flange 6 of the bush 5 includes a groove 12 for the reception of a sealing ring 13 and carries a collar 24. A valve housing 15 is snappable by its collar 16 on this collar 24. By this means, the electromagnet is connected with the valve housing into one unit. The valve housing 15 consists of a part of plastics material or is formed by a chamber of an appliance container and has an inlet nipple 19, a valve seat 21, a valve passage 22 and an outlet opening 23.

i The valve seat 21 carries a valve seat seal 20 of rubber or plastics material.

The throughflow direction of the valve is indicated by the arrows in Fig. 1.

Mounted on the head 7 is a seal 4, which is provided with a constriction 25 in a recess 26 for the head 7 and detentably movable relative to this. The seal 4 consists of a spherical portion 14, which can enter into the valve passage 22 of the valve seat seal 20, and a flange 17, which is integral with the portion and which has an annular sealing edge 18 resting against the seal 20 for the closing of the valve.

As is evident from Fig. 2 (closed setting), Fig. 3 (valve before the final closing setting or in the first opening setting) and Fig.

4 (valve opened), the valve can be closed and opened with the valve seat arranged obliquely relative to the armature 10. In the open end setting, the seal 4 is raised clear of the seal 20 and frees the passage 20 for a large throughflow.

In the closing phase, the spherical portion 14 enters into the passage 22 and initially comes into contact with the seal 20, for example, at the point 27 of the sealing edge 18, whilst a gap 28 remains present opposite the point 27. During further closing operation, the sealing edge 18 rolls along the seal 20 and closes the passage 22 through line-shaped, annular contact with the seal 20.

During opening of the valve, a gap 28 is firstly created for water flow, which then assists the opening movement of the valve in a manner of a servo-bore.

The electromagnetic valve embodying the invention as hereinbefore i j i i 1 i i i 1 - 7 described is particularly suitable for use in water softening equipment of a dishwashing machine or in an automatic beverage dispenser.

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Claims

1. An electromagnetic valve comprising a valve housing defining an inlet passage and an outlet passage and provided between the passages with a valve seat having a seating seal, an armature carrying a valve member co-operable with the seal, resilient means- acting on the armature to urge the valve member towards the seal, and a coil extending around the-armature and effective when energised to displace the armature against the force of the resilient means, the valve member being mounted on a ball head of the armature for pivotal movement 10 relative thereto.

2. A valve as claimed in claim 1, wherein the coil is arranged in a coil housing and the armature is slidably guided in a bush in the coil, the bush being provided with a flange which bears against the coil housing and which has a collar engaged in a collar of the valve housing.

3. A valve as claimed in either claim 1 or claim 2, wherein the valve member is provided with a part-spherical portion engageable in an opening of the valve seat and with a flange portion having an annular sealing edge arranged to contact the seal of the seat when 20 the valve is closed.

4. A valve as claimed in any one of the preceding claims, wherein the valve member is retained on the ball head of the armature by detent means.

-- 1 1 i j I i 1 j I i 1 i 1 i j i I i 1 i 1 k 9.

5. A valve as claimed in claim 3, wherein the valve member is so pivotable relative to the armature and to the seal of the seat that on energising of the coil to displace the armature the annular sealing edge initially pivots in one side region thereof away from the seal and thereafter moves entirely away from the seal.

6. A valve as claimed in either claim 3 or claim 5, wherein the valve member is so arranged relative to the seal of the seat that pressure when present in the inlet passage means acts to assist holding of the annular sealing edge against the seal of the seat.

7. A valve substantially as hereinbefore described with reference to the accompanying drawings.

Published 1988 at The Patent Office, State House, 66.71 High Holborn. London WC1R 4TP. Further copies maybe obUdned from The Patent Office, Sales Branch, St Mary Gray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Gray, Kent. Con- 1187.