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DESCRIPTION Set of valves for piston compressor
The invention relates to a set of valves for a piston compressor, comprising a suction valve and a discharge valve arranged concentrically with the suction valve, each of these valves having a seat plate in which are provided perforations and a valve plate being disposed between these two seat plates and associated with each of the suction and discharge valves, each of the valve plates being held between the seat plates by at least one link arm.
Such a set of valves is known from FIG. 2 of document DE-AS 18 12 580. In this set of valves, the two seat plates are tightened one towards
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the other by means of a central nut assembly and the link arms joining externally on each of the two valve plates are held, at their free ends, by studs which are fixed in the seat plates. There is a relatively large radial gap between the studs which hold the connecting arms of the inner valve plate and at the inner edge of the outer valve plate, so that a seal must also be provided in this area. the two seat plates so that the suction valve is gas-tight from the discharge valve.
This embodiment of the valve set results in a relatively large diameter of the valve set, which is linked to an even greater space requirement on the compressor.
The object of the invention is to improve a set of valves of the type described at the start, in order to reduce the diameter and therefore the need for space.
The object is achieved according to the invention by the fact that the inner edge of the outer valve plate and the outer edge of the inner valve plate each have a firm ring, attached to the
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associated link arm, and by the fact that the two valve plates are tightly fixed on these two firm rings, between the seat plates. Due to the presence of the closed rings, which are close to each other and which can have relatively small dimensions, it is possible to limit on a small annular area the fixing of the two valve plates between the seat plates , which makes it possible to significantly reduce the maximum diameter of the valve clearance in comparison with that of the known clearance.
In addition, it is possible to eliminate the central fixing with the seat plates, which also goes in the direction of a reduction in diameter because the space freed in the central axis of the set of valves is now made available for circulation. carbonated. The manufacture of the new valve set is very simple, by the fact that the two valve plates are first manufactured in one piece which is then separated to form the two valve plates, by means of a process of laser cutting.
The invention will be described in more detail with reference to the attached drawing by way of nonlimiting example and in which: - Figure 1 is a section of a set of valves along the line I-I of Figure 2; and - Figure 2 is a plan view of the two valve plates assembled one inside the other, on a slightly reduced scale compared to that of Figure l.
As shown in Figure 1, the valve set consists essentially of two seat plates 1 and 2 arranged one on the other and two concentric valve plates 3 and 4 mounted between these two seat plates. The seat plate 1 forms, with its central part and the internal valve plate 3, a suction valve for a compressor which is not
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shown in more detail and whose compression chamber 5 extends below the seat plate 2. The outer annular part of the seat plate 2 and the valve plate 4, of annular shape, constitute a discharge valve having, in cross section, an annular shape.
The seat plate 1 has, in its central part, perforations 6 in the form of a slot which extend on arcs of a circle concentric with the median axis 7 of the valve set, without however forming a complete circle. In FIG. 1, there are provided, in the seat plate 2, below the central part of the seat plate 1, perforations 8 in the form of slots of the same extent as that of the perforations 6, which perforations 8 are however offset towards the outside, on a radial half, with respect to the perforations 6. The perforations 8 widen towards the compression chamber 5 in the manner of diffusers. In addition, a perforation 8 ', flaring like a diffuser, is located in the center of the seat plate 2.
The valve plate 3 has perforations 20 in alignment with the perforations 8 and 8 '.
The plate 3 of the suction valve is pushed against the seat plate 1 by eight springs 9. The distribution of the springs 9 on the valve plate 3 is represented by dashed circles in FIG. 2. The springs 9 are arranged in corresponding housings 9 ′ of the seat plate 2. The gas to be compressed flows in the direction of arrow 10 through the central part of the seat plate 1, which has the effect of moving the valve plate 3 downwards, against the force of the springs 9, so that the gas arrives in the compression chamber 5 through the perforations 6, as well as 20, 8 and 8 '.
The annular valve for discharging the valve set concentrically surrounds the suction valve.
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The valve plate 4 is pushed back against the seat plate 2 by four springs which are not visible in FIG. These springs therefore correspond to the springs 9, but are distributed over the extent of the valve plate 4 (dashed circles in FIG. 2) and inserted into the upper seat plate 1. The seat plate 2 also has perforations 12 in form of slots, corresponding to the perforations 6 of the seat plate 1, which also extend over an arc of a circle, but however not over the entire circumference: Perforations 13 of the seat plate 1 are associated with the perforations 12.
The valve plate 4 has perforations 21 aligned with the perforations 13 located inside. During the compression phase, the compressed gas flows - under the effect of the detachment of the valve plate 4 relative to the seat plate 2 - in the direction of FIG. 14. The arrival of the gas to be compressed ( arrow 10) and the outlet of the compressed gas (arrow 14) are separated by a closed annular wall which is represented by the mixed lines 15 in FIG. 1.
As shown in FIG. 2, the valve plates 3 and 4 are arranged one inside the other concentrically. The outer valve plate 4 is connected by four connecting arms 4 ′ to a closed inner ring 4 "for fixing. The valve plate 3 located inside is similarly connected by four external connecting arms 3 ′ to a 3 "external fixing ring.
As shown in Figure 1, the 3 '' rings
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and 4 "of fastening, closely adjacent to each other, are clamped between the seat plates 1 and 2. The tightening force is applied by means of four screws 16, only one of which is visible in FIG. 1 and a by means of which the seat plates 1 and 2 are clamped towards each other. It is provided, in the transition zone of each
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arms r 'of connection in the fixing ring 4 ", a notch 17 in the shape of a semicircle (FIG. 2) for the screws 16. The arms 3' and 4 'of connection ensure the mobility of the plates 3 and 4 valve with respect to the respective 3 "and 4" fixing rings.
The valve plates 3 and 4, initially manufactured in one piece, are, at the end of the treatment, divided into two plates by a laser cut 22 in which it is provided, on the trace of the cut otherwise carried out according to a circle, a smaller semicircle 23 extending inwards, by means of which the fixing ring 4 "retains a stud which fits into a groove in the form of a semicircle. The two plates 3 and 4 can thus not rotate relative to each other during assembly.
Unlike the example embodiment described, the notches 17 in FIG. 2 can each be shifted in an anticlockwise direction up to the line at 45 *, the transition zone between the arms of connection 4 ′ and the valve plate 4 being shifted correspondingly at the same time
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or reduced to a dimension somewhat smaller than that shown in FIG. 2. An embodiment thus modified has the advantage of allowing the use, for example of the valve plate 3 - in the case where it presents traces of deterioration on the surface cooperating with the seat plate 1 -, in such a way that the surface, previously in contact with the springs 9, then cooperates with the seat plate 1.