Many types of valves are known, where the construction of the closing element varies according to the purpose of use and in order to achieve a required characteristic curve. For stream adjustment valves have been used, to the spindle of which for the adjusting function a linear motion is brougth. The spindle linear motion opens or closes the port. A problem has been accumulation of sludge or mass contained in the flow, which has caused changes in the qualities of flow and penetration of mass to the sliding surfaces of flow or corresponding closing element, which has caused valve stagnations.

For instance, from the printed German patent specifications 691334 and 625297 valves are known with a small pressure drop in opened state, but disturbed flow in intermediate positions. Disturbance occurs in the flow only after the closing element. With regard to their type, these valves are not suitable as adjusting valves for mass flow.

By means of a valve according to this invention the frequent problems are avoided and substantially better qualities by mass flow adjustment achieved. The invention is characterized in what is presented in the claims.

The advantage of the invention is that on the most used part of the characteristic curve stream flow takes place cleaning the valve so that there is no sludge accumulation in the valve interior part, flow takes place with a pressure drop proper to the use and the dependence of flow quantity on the linear motion is easily determined or known. When the adjustable flow hits the bevelled lower surface of the closing element, the pressure drop then begins to get formed already at the closing element.

In the following the ivention is disclosed with reference to the enclosed drawing, where Fig. 1 is the cross profile of the valve.

Fig. 2 is the valve viewed from the port direction.

Fig. 3 is the lower end of the spindle working as closing element.

Fig. 4 is a side view of the closing element lower end.

Fig. 5 is another embodiment of the closing element lower end.

Fig. 6 is the cross profile of the closing element lower end.

Figure 1 shows a valve, where in the face portion 2 an outlet 4 is drilled as well as a cylindric bore, perpendicular to said outlet, for the valve closing element 1 and its bushing 3. For adjustment of the outlet size the closing element 1 is moved linearly in bushing 3. Most favourably, the bushing is of plastic, Teflon, for instance, whereat closing element 1 can even be compressed in order to produce sealing but retaining the sliding capacity of the closing element due to the excellent sliding qualities of Teflon. By means of this solution pene- tration of sludge and liquid between closing element 1 and bushing 3 is avoided. Compression is produced for instance in dimensioning the bushing 3 diameter with respect to the bore in housing 2 and the closing element 1 diameter. Another alter- native is a tension nut 7 by means of which flange ring 8 is tensioned towards bushing 3 making it press bushing 3 longi- tudinally. The compressed bushing tightens the sliding surfaces.

Elements 6 are rotation stoppers. One of them prevents the flange ring 8 from rotating by leaning on housing 2 and the other one prevents the closing element 1 from rotating by lean- ing on the flange ring 8 groove.

Figure 2 shows the way by means of which the port orifice is formed between closing element 1 lower end and flow channel portion 4. The lower end of closing element 1 is bevelled and includes a groove 5 growing deeper from the inside so that this groove 5 is deepest on the closing element edge from where the flow to outlet 4 takes place. The Dh ratio of outlet 4 hydrau- lic diameter to the closing element 1 hydraulic diameter ranges from 50 to 120 %. The hydraulic diameter Dh = 4 x cross-area/ perimeter.

Figure 3 shows simply the lower end of the closing element 1 illustrating the formation of the bevelled groove portion 5. The oblique angle a of groove 5 bottom with respect to the closing element longitudinal axis ranges from 80° to 20°. The groove is only on a part of the closing element lower end surface. By oblique angel ß levels 9 remain on both sides of groove 5. The ratio of groove diameter of groove portion 5 to hydraulic diameter Dh of the outlet 4 in the most narrow port orifice most favourably ranges from 50 to 120%. Flow channel 4 is circular or it can also be a slightly elliptic or oval hole or a quadrangle with rounded corners at bushing 3. In the invention it is favourable that only a part of the closing element lower surface is formed by the groove portion 5, then the flow can better find its way to outlet 4.

Consequently, the adjustable port is most suitably transformed as an orifice restricted by the side projection of two circular or two slightly elliptic openings. A part of the flow gets into whirling immediately after the bushing 3 orifice and the whirl effect keeps channel portion 4 clean. With the valve fully open, there is hardly any whirling but, on the other hand, the velocity of flow hardly decreases after the orifice, which would result in accumulation of sludge.

Figure 4 shows the oblique angle P of the closing element planelike lower end 9, which angle can vary within the range from 5° to 45°. The same range of variation suits also the oblique angle ß of the groovelike lower face 10 in figure 5.

Figure 5 shows the faces 10 on both sides of groove portion 5, which in the oblique angle P can also be groove portions in the flow direction, whose groove diameter is substantially greater than the groove diameter of groove 5.

Figure 6 shows a bevel 11 made on the groove portion 5 outlet side in order to make the arrival of flow at port 4 edge more gentle. Also on the edge of port 4 orifice at bushing 3 there can be a bevel, especially in the lower part (fig 1.) Since in adjustment situations the valve is not even near to its closing position.

The bore for bushing 3 and closing element 1 can be round, oval, angular or a combination of the same.