FI64995B - AUTOMATISK REGLERINGSVENTIL - Google Patents

Description

AUTOMATIC CONTROL VALVE - AUTOMATISK REGLERINGSVENTIL 6 4 9 9 5 /

The invention relates to an automatic adjustment valve without exchange equipment, which is intended to pass a substantially constant volume of air per unit of time without the supply side and the air outlet side between the varying degrees of pressure differential, which comprises a control flap which is pivotally mounted vent brick housing horizontal axis and to place means for adjusting the flap toward the closing position movement of the resist, wherein the flap part above the axis of the control flap is arranged to pivot against the direction of the air flow towards the vertical plane in connection with the closing movement.

One problem with such valves is that the resulting closing moment caused by the air flow increases very strongly as the flap approaches the closing position, and this causes the movement of the flap to stop abruptly. In order to prevent such sudden closures, it has been proposed to resist the pivoting movement of the flap by a spring member, the counterforce of which increases in degree in proportion to the increase in the moment of closure. However, the uncertainty becomes high, and when the flap is used, the properties of the spring change over time, and so gradually rapid closures begin to occur, causing greater noise and poor adjustment.

Further attempts have been made to avoid said disadvantage by setting the tongue of the flap plate, which is in the air flow and which increases the closing moment when the flap is open and gradually reduces this moment when the flap moves towards its closing position. Such a device, which is described, for example, in Swedish Patent Application Publication No. 302677, works perfectly, but is expensive to manufacture, and the tongue must be positioned exactly relative to a flat flap plate.

Therefore, the main object of the invention is to provide a control valve of the type mentioned in the introduction, which is inexpensive and has the same good properties as the known valve f with a control tongue in the flap plate. The control valve according to the invention is characterized in that the contours of the edges of the control valve are shaped, depending on the position of the pivot shaft in the valve housing, so that when the flap is closed a perforated opening surface, whereby in the closing region of the control flap, with a constant air flow, a relatively greater increase in the amount of air flowing through the control flap part below the shaft than in the control flap part above the shaft is achieved.

The invention will now be described in more detail by way of example with reference to the accompanying drawings, in which

Figure 1 is an axial section of a control valve of a known type to illustrate the forces present in the flap plate,

Figure 2 corresponds to Figure 1, but shows a flap plate according to the invention,

Figure 3 shows the device according to Figure 2 seen in the direction of discharge,

Figure 4 shows the flap plate of the device according to Figures 2 and 3 in the closed position.

Figure 5 shows a modified flap plate of the device according to Figures 2 and 3,

Figures 6 and 7 show other flaps according to the invention.

Figure 1 illustrates a simplified manner the principle of the prior-Control Valve, Slew valve, a valve through which the air flows in the direction of the arrow shown and the valve in spite of the pressure drop passes a constant or substantially constant amount of air.

Arranged in the valve housing 1 is a flap 2 pivotable about a horizontal shaft 3. The shaft 3 is rotatably mounted on low-friction bearings not shown here, for example 3 64995 ball bearings. An arm 4 with a counterweight 5 is firmly attached to the shaft 3 or the flap 2. The main purpose of the counterweight 5 and the arm 4 is to provide a torque M2 which acts against the closing movement of the flap caused by the torque M1, i.e. torque caused by air flowing through the valve. This moment is due to the fact that it is known that the flow rate in front of the flap and in the position shown at the upper edge of the flap relative to the air flow exceeds the flow rate at the front and lower edge of the flap and that the flow rate at the flap can also be expressed such that Pj <p4 and Pi <P2.

In a certain position of the flap, the amount of air in the duct increases while the pressure drop at the flap 2 increases, the increase in the pressure drop in turn causes an increasing torque M 1, which causes the flap to settle in a more closed position. Of course, as the flap moves towards the closing position, indicated by dashed lines in Fig. 1, the structure shown in Fig. 1 will also increase the counter torque M2. Based on the edge effects, the closing torque will increase more or less abruptly when the flap comes close to the closing position. This causes the flap to close rapidly, stopping at the stop 13 or colliding with the inner wall of the housing 1,

According to the invention, the effect of this edge phenomenon, which occurs in the vicinity of the closing position, is eliminated by reducing the torque and thus an equilibrium can be achieved by means of the counter-torque M2 so that the movement of the flap becomes smooth and calm throughout the area. The invention is based on the fact that in and near the flap closure area the amount of air passing below the flap 2 increases relative to the amount of air passing above the flap, i.e. the flow rate increases below the flap (static pressure decreases) and above the flap 2 the flow rate decreases pressure increases). This, in turn, means that the closing torque decreases as the flap 2 approaches the closing position, and the counteracting torque M2 can then be adjusted so that the weight lever or the spring-loaded lever gives an air volume independent of the pressure drop.

A certain increase in the amount of air below the flap (according to Figure 1 in the closing direction) can be achieved by reducing the surface of the flap 2 below. Figures 2, 3 and 4 show an elliptical flat flap 2 in which the edge portions 8 'and 9' (Figure 4) are folded up substantially perpendicular to the plane of the flap and in the flow direction to form the grooves 8 and 9. This reduction of the part of the flap below the pivot axis causes that when the flap moves towards the closed position, the the area of the part decreases in relation to the area of the part of the flap above the shaft, and then also in the vicinity of the reduced torque in the closing position, as described above.

Of course, the reduction of the closing area of the label part of the flap a in the vicinity of the closing position can also be achieved by cutting off the lower tip of the ellipse according to Fig. 4 or removing the parts 8 'and 9' instead of folding them. It is also possible to provide flow-through openings according to Figure 5, which would be achieved without an increase in velocity in the closing zone.

Non-linear modification of the gaps between the through-slots, s, o, the inner wall of the housing 1 and the parts of the flap plate above or below the horizontal pivot shaft 3 can also be achieved by placing the pivot shaft below the center of the plate or moving the bearing points 6, 7 upwards. Such an embodiment in which, in addition, the flap plate 2 'is circular and the pivot shaft 3' is below the center of the plate is shown in Fig. 6, while Fig. 7 shows an embodiment with bearing points displaced relative to the shaft 3.

64995

Although the flap has been assumed above to consist of a flat plate, it is obvious that it can also consist of a plate with one or two bends. The shape of the plate and the line are also irrelevant, and it is thus possible to use a valve housing with a rectangular cross-section and a rectangular or square flap placed therein.

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Claims (5)

1. Automatic control valve for ventilation systems, the icon is intended to pass through a substantially constant air volume per unit time at varying differential pressures between the air inlet side and the air outlet side, which control valve comprises a control valve (2) rotatably stored in a valve housing ( 1) on a horizontal shaft (3) and comprising means (4,5) for counteracting the movement of the throttle to the closing position, the throttle portion located above the shaft (3) being arranged to pivot towards the air flow direction and to a vertical plane below the closing movement, characterized in that, depending on the position of the pivot shaft (3) in the valve housing (1), the control damper (2) has such an edge contour (Fig. 4, Fig. 7) that in a closed position it provides a gap opening between its damper surface (2.21) and the wall of the valve body (1), which differs substantially from an evenly wide gap opening and / or has a pierced gap surface (Fig. 5), so that in the constant damper air passage phase, a relatively greater increase in throughput of air on the part of the control damper lying under the shaft (3) than on the part lying over the shaft. 2. An actuating valve according to claim 1, characterized in that the control damper (2) consists of a symmetrical disk around the shaft (3). 3. A control valve according to claim 1 or 2, characterized in that the part of the control damper located under the shaft (3) has curved edge portions (8,9). Control valve according to claim 1 or 2, characterized in that the part of the control damper located under the shaft (3) has one or more cut-outs (8 ', 9'). Il