Iris diaphragm control valve

The invention concerns a screen flow control valve for the flow control of a flowable medium, whereby a number itself mutually more affecting into the flow channel of importable, flat screen elements between two housing halves arranged and by one likewise in the housing accommodated driver ring propelable ist.

3,637,457 squeezes an O-ring 6, which is in this groove 5. The upper housing plate 1 is provided with a cylindrical recess 7, into which six screen elements 8 and a driver ring 9 stored sind.

As from the Fig. 4 and 5 comes out, has the screen elements essentially the form of an equilateral triangle, whose is tapered, to the edge 4 neighbouring corner 10 from space reasons. Two neighbouring screen elements each 8 touch themselves along their common thigh edges 11, whereby these thigh edges 11 are gradated and both lo the function of a guidance and a sealing between the neighbouring elements 8 übernehmnen.

Each screen element 8 exhibits two guide pins 12, 13, at their ends per a Ftihrungsbuchse 14 rising up downward screwed on ist.

A a guide pin the 13 is on the bisector 16 of the two gradate-like shifted thighs 11 and exhibits an upper, cam-like extension 15, which is eccentrically arranged to the axle of the pin 13. As is later still more near described, the exact situation of the screen elements can relatively to each other adjusted werden.

by means of the eccentric cam 15 In the lower housing plate 2 six, an equilateral hexagon screen end, straight guide grooves 17 are left blank for the admission of the Ffihrungsbuchsen 14 of the screen elements 8. the guide grooves 17 have all regarding the axle 30 of the Durchflussöffnung 18 the same radial distance. One end each of the slots 17 is over the respective corner verlängert.

Each screen element 8 is tangential led to the Durchflussöffnung 18 by the guide grooves 17. In the closed position the points 19 of the screen elements 8 into the Durchflussöffnung 18 project, and the gradated thigh edges 11 are taken off by the ribs 20 of a star 21, the component of the lower Gehäuscplatte 2 are and likewise into the Durchflussöffnung 18 hineinragt.

Those the screen elements 8 course-turned edges of the star are flat and lie in the same level as the disk inner surface 22. The star forms a guidance surface for the slidegate valve elements together with the disk inner surface 22 8. these becomes by the seepage pressure against this guidance surface 22 gedrückt.

To open the valve the slidegate valve elements 8 in their slots 17 are moved together, whereby a centric, hexagonal Durehflussquerschnitt develops, which extends increasingly, until the screen elements concerned in their end position sind.

The adjustment of the screen elements 8 takes place via the driver ring 9, that in the recess 7 of the upper housing plate 1 accommodated ist.

In the driver ring 9 six diagonal, broken Führungsschlitze 23 are left blank, into which the cams 15 of the guide pins 13 of the screen elements project. For the twist of the driver ring a Zahnritze124, whose axle 25 the lower housing plate 2 durchdñngt, serves 9. The Zahnritze124 combs with a gear rim segment 26 at the outer circumference of the driver ring 9.

The mutual situation of the screen elements 8 can be stopped and adjusted by rotating the eccentric cams 15 exactly. In the open position of the valve the Nockcn 15 is in the section 23a of the Führungsschlitzes 23. Now for closing the valve if the driver ring 9 is rotated, then the screen elements 8 are shifted into the Durchflussöffnung of the flowing medium inside, until the opening approximately completely finally ist.

With this position of the screen elements 8 the cams 15 are in the range of the break of the Führungsschlitzes 23 and the guide bushes 14 within the range of radial extensions 27 of the guide grooves 17 of the housing plate 2. now the driver ring 9 are continued to rotate, then the cams 15 arrive into the sections of the Führungsschlitze 23 marked with 23b, whereby on the screen elements 8 a increased radial force component einwirkt.

The guide bushes 14 penetrate 27 of the slots 17 into the radial extensions, so that the screen elements are against each other radially blocked, in order to obtain a high sealing effect. The points 19 of the screen elements 8 are appropriately blunted, as inFig. 4 under the number 28 shown is. The closing edges 11 and the blunted points 19 are complete by the guidance star 21 abgedeckt.

Also the upper housing plate 1 can be provided with a Führungsstem 29, so that the screen elements 8 within the Durchflussöffnung 18 between the two stars are led. In order a increased clamping effect in the closing situation too received, the screen elements could be above bent wedge-shaped. Also the appropriate surfaces of the assigned star 29 could tapered sein.

Instead of the wedge-shaped and/or tapered surfaces also different means could be used for the production of a blocking, e.g. bevel ribs at the screen elements, those shortly before complete closing of the valve with the ribs of the star in interference kommen.

With other execution forms slots can be left blank, are inserted into which weatherstrips, those against the contact edges 11 of the screen elements 8 are pressed with closed Ventil.

in the ribs 20 of the stars The screen elements can exhibit different forms, e.g. four rectangular elements or also a majority of crescent-shaped elements. The ribs of the stars must then likewise accordingly trained sein.

It is substantial that the segment guidance always around 90° for the bisector of the segment point in the closed situation erfolgt.

That managing described screen flow control valve exhibits the following advantages:

By appropriate arrangement of the pin guidance in the tension ring in the closing situation the movement of the segments is changed in the way that they experience a Zentralbewegung to the center. Thus a pressure at the flanks develops, for that the mutual sealing of the elements verbessert.

By the inclination of the segments and appropriate surfaces of the guidance star in the upper section becomes in the last phase of reasoning, with which, a pressure between the two guidance stars produces radial movement of the segments, i.e. the segments are pressed on the display surfaces and seal ab.

In each position, except the closing position, the screen elements run loosely one on the other and are loosely led by the gradated thigh edges. The friction forces are much gering.

The guidance of the tension ring is ensured by the recess in the upper Gehäuseteil. The drive of the tension ring is made in very simple way by the gear rim and the pinion. The wave of the pinion led outward can be sealed over a shaft seal. It can connected with each kind by drive, e.g. motor or manually, sein.

The descriptive screen flow control valve does not cause noises, since its design is expressed flowfriendly. Compared with conventional valves higher flow rates can mastered werden.

with same noise level As was initially mentioned, the adjusting force affects itself with conventional valves voli against the system pressure. This has the consequence that the adjusting force must be ever larger than the system pressure. Depending upon application one makes do with the conventional valves with Druckausgleicheinrichtuugen. which however a higher manufacturing expenditure and higher costs causes. With the available screen flow control valve adjusting force works the 637,457 4 no longer against the system pressure, separates uses it, in order to improve the sealing effect. The adjusting force amounts to only a fraction of the system pressure. So also large flow rates with minimum adjusting force can accurately regularly werden.

The adjustment drives can be specified smaller and to a large extent independently of the flow rate. This has the consequence that all drive systems can to be used and obtain a high precision in the regulation leave/> The KVR value indicates the smallest adjustable flow rate, related to the maximum flow rate. With conventional valves the KvR value is with 5 to 10%. With the available valve is the KvR value far lower and comes very close at 0% heran.

The screen flow control valve is developed constructionally very simple and exhibits very small dimensions, so that problem-free anch into pipings are later built kann.

The tightness is comparable with the tightness of conventional stroke valves, so that the latters can be replaced easily by the available valve. Due to its small thickness it can be inserted e.g. simply between two flanges of a piping, whereby the drive between the flanges must be outward led. This constructional training of the drive might be clear for the specialist and requires no further Erläuterung.

M 2 sides designs 637,457 2 sheets sheet 1: Fig.1 18 - V/Æ////A // ', f, t < 447, l cri, oI rííJ 9 Ix, \ \ \ \ '1 OE \ \ \ “i.,… 26 13 U L 4 ./1 =1 6 _ 22 17 27 18! 1111124 Fig. 2 26 24 9 IX 23a 13 23