The present invention relates to a valve device, including a valve casing having at least three ports, two of which being angularly oriented relative to one another and each one having an individual valve, one of the valves being held in its open position when the other valve is held in its closed position, and vice versa. The invention re¬ lates particularly, but not exclusively, to a valve devi¬ ce for regulating and distributing fluid streams from two ports to a third port, or alternatively from one port to

10 two other ports. Such valve devices are often being used as so called shunt valves in hot water systems.

The valves of the known valve devices are often designed as rotary slide valves, and usually as so called plane

15 slide valves, where the fluid flow is regulated by means of a slide in the shape of a plane disc ha ing an aper¬ ture or a recess and being rotatably mounted relati e to an opening in the casing. When using this type of valve, the operation of which is performed by rotation of an ope¬

20 rative shaft or spindle is it difficult to achieve an adequate sealing of the inlet and outlet of the valve. In order to i prove the sealing, the valve is usually mounted in a manner where the plane disc is urged against the valve casing by means of a compression spring.

25

When making greater demands upon the sealing efficiency, seat valves are instead used in the shape of wedge-gate valves. These have an axially displacable wedge gate having a conical abutment surface being designed to seal

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30 against a mating conical seat in the valve casing. The wedge gate can be operated either by an axially displacab¬ le operative spindle or by a rotatable operative spindle, the rotary movement of which is being transformed into an a ial ^' displacement of the wedge.

35

Although the wedge-gate valve has often a better sealing function than the plane slide valve, the cost of manufac¬ ture is higher, which makes the valve device more expen¬ sive.

The object of the present invention is, therefore, to pro¬ vide a valve device of the aforementioned kind which enab¬ les the use of two different valves, each of which having an individual sealing efficiency adapted to its respective demand. This object is achieved by a valve device in ι accordance with the invention having the characterizing features set forth in Claim 1.

The cheaper type of valve, i e the rotary slide valve, can, in accordance with the invention, be used in a port having a reduced sealing requi ement, for instance in the case where it comes to return water from a radiator or the like, whereas the more expensive valve, i e the wedge-gate valve, can be used in a port having a grea er demand upon the sealing efficiency, for instance in the case where it comes to conveying water from a heating device. In accordance with the invention the two valves are controllable simul¬ taneously by means of a common operative spindle capable of rotating the rotary slide valve and affect the wedge- gate valve axially as well, for instance via an eccentric.

According to a further embodiment of the invention a soft sealing means is mounted in the wedge-gate valve- between the valve body and the seat, the operative spindle being capable of displacing the valve body from a closed to an open position against the action of the pressure prevai¬ ling outside the port, and against the action of a spring. This means that the soft sealing means will, in the closed position of the valve, be compressed, i e seal better at higher pressure from the fluid outside the port.

Further developments of the invention are set forth in the dependant Claims.

The invention will be described below in more detail with reference to the accompanying drawing which illustrates a preferred embodiment of the invention.

Fig. 1 is a cross-sectional view of a valve device accor¬ ding to the invention and designed for mixing a return water from a heater, for instance a radiator, and feed- water from a heating device. Fig. 2 is a plane view of an eccentric incorporated in the valve device of fig. 1. Fig. 3 is a plane view of a plane slide incorporated in the valve device of fig. 1.

The valve device includes a casing 1 with three ports 2, 3 and 4, the centre axises of which are oriented in a common plane, but which in said order are displaced 90 degrees relative to one another.

The port 2 is an inlet port, and is designed to be supp¬ lied with feed-water from a heating device, not shown. The port 3 is a shunt port, and is designed to be supplied with return water from a heating device, for instance a radiator. The port 4 is always open, and designed to supply water to an inlet conduit (not shown) for the hea¬ ting device.

The ports 2 and 3 are prov ded with a wedge-gate valve 5 and a plane slide valve 6, respecti ely, the two valves being simultaneously controllable by a common rotary ope¬ rative spindle 7 being oriented coaxi ally with the port 3. The operative spindle 7 is arranged to be driven by a drive motor, not shown, which preferably is controlled in a way known per se, by one or more conventional thermal transducers (not shown). The operative spindle 7 is rigidly connected to the plan slide of the valve 6 which has the shape of a circular plane disc 6a which abuts against a seat όb in the port 3. The disc 6a has a semi¬ circular aperture 6c, wh ch is tapered in one direction

(see fig. 3), and which, as a result of the rotation of the operative spindle 7, varies its open area relative to a semicircular slot 6d of uniform width provided in the seat 6b. The disc 6a is held compressed against the seat 6b by means of a spring 6e arranged around the spindle 7, the spring 6e being compressed between the disc 6a and ring member 6f which is ridigly connected to the spindle 7,

A cam in the form of a circular disc 8 is, via an eccent- ric bore 8a, threaded on to the spindle 7 wπ ^' thin the casing 1 flush with the port 2-and is rigidly connected to the spindle 7. The disc 8 thereby forms an eccentric (see fig. 2), by the aid of which the operative spindle 7 can transmit its rotary movement to an axial force on the wedge-gate valve 5.

The valve 5 is provided with a seat 9 which widens coni- cally towards the exterior of the port, a correspondingly conically shaped valve body in the shape of a wedge member 10 being designed to sealingly abut against the seat 9 via a soft sealing means in the shape of an 0-ring 11 being arranged in a groove of the wedge-gate. The wedge-gate 10 is thereby dimensioned to abut the seat 9 before the 0-ring 11 will be entirely compressed, thus increasing the life time thereof.

The wedge member 10 is axially displacable in a guide means 10a in the port 2, the periphery of the wedge mem¬ ber having a number of axial recesses 10b facing the guide means 10a and forming the actual fluid passages of the valve 5.

The wedge member 10 has an axial centre channel 10c having a second seat 10d which widens conically towards the exte- rior of the port 2, a correspondingly conically shaped release wedge member 12 being arranged to abut against said second seat by means of a compression spring 13.

This is compressed between the wedge member 12 and a spoke wheel ring 14 which is radially mounted in the wall of the port 2. In order to retain the spring 13, this is arran¬ ged around a pin protruding from the wedge member 12 and also arranged around a pin protruding from the ring 14.

The release wedge member 12 has an operative pin 12a in its end portion that faces the valve casing 1, the pin being urged against the eccentric disc 8 by the spring 13.

The valve device operates as follows:

In the position shown in Figs. 1-3 the valve 5 is comple¬ tely closed, whereas the valve 6 is completely open. Upon rotation of the operative spindle 7, the eccentric disc 8 will, against the action of the spring 13, displace the release wedge member 12 downwards, the valve 5 thereby partially opening such that a certain amount of fluid can drop past between the wedge member 12 and the seat 10d. The wedge member 12 thus serves as a pressure release for the wedge member 10 and as a control wedge-gate as well, in the opening phase of the valve.

When the pin 12a is entirely displaced downwards in the wedge member 10, the valve wedge member 10 and the relea¬ se wedge member 12 as well, will be displaced downwards by the eccentric disc 8, such that the valve 5 will be further opened, causing fluid to stream also through the channels 10b. The more the inlet port 2 will open, the more the shunt port 3 will close by means of the plane slide 6a, the outlet 6c of which will reduce its opening area against the seat 6b. Upon a rotary movement of 180 degrees from the starting position, the eccentric 8 has displaced the wedge members 10 and 12 to a maximum, i e the valve 5 is entirely open. Simultaneous-ly, the outlet 6c of the plane slide 6a will be entirely closed against the seat 6b .

Thanks to the described arrangement of the two wedge mem¬ bers 10 and 12, the valve 5 can be made entirely free of leakage in its closed position without any need of cost consuming precision work having to be done.

The valve casing 1 may be manufactured of any suitable cast-metal, for instance red casting, whereas the valve bodies suitable are made of acid resistant stainless steel The release wedge member may alternatively be made of a plastic or the like. /

The capacity value (cvs-value) may be varied by adjustment of a maximal rotary angle of the operative spindle.

In the embodiment shown, the inlet port 2 and the shunt port 3 form a 90 degrees angle with one another. Accor¬ ding to an alternative embodiment the ports may form a different angle relative to one another, for instance by inclining the disc correspondingly against the spindle 7.