CLAMPING DEVICE FOR EXPLOSION PANELS

Abstract: The invention is for a clamping device for holding an explosion panel on the safety opening of a holder in which there is a dust, gas or vapour, which explosion panel will in the event of an excess of pressure, for example as a result of an explosion in the holder, be thrown open or blown off so that the holder sustains little or no damage. The explosion panel (10) is made of rigid material and is equipped with a retaining edge (8) on which the free end of clip strips (6) fastened at an angle to a frame provided around the safety opening (2) of the holder (1) engages, which clip strips press the explosion panel (10) onto the frame.

Description: The invention relates to a clamping device with an explosion panel held on the safety opening of a holder in which there is a dust, gas or vapour, which explosion panel will in the event of an excess of pressure, for example as a result of an explosion in the holder, be thrown open or blown off so that the holder sustains little or no damage. Such devices are known in a variety of embodiments. In a known embodiment use is made of a flexible panel which can be held on the holder by a variety of means. In the event of an explosion in the holder the panel bends and the perimeter of the panel comes free of said means so that the panel is blown off. However, because the opening pressure is governed in part by the bending of the panel a new panel must be designed and tested for every specific opening pressure. In another known embodiment the means of retaining the panel consists of a number of leaf springs located around the perimeter of the panel, one end of which is mounted on the panel and the other end of which fits into a slot of a perpendicular support or frame mounted on the holder. In the event of an explosion the panel is pressed upwards and each flexible spring slides out of the slot of its support, so that the panel is blown off and the safety opening of the holder is cleared. A major disadvantage of this is that the springs do not permit a good seal between the panel and the perimeter of the opening to be achieved. In order to remedy this to some extent, it is necessary to give the panel a relatively complicated shape. Yet another disadvantage is that the springs do not retain their springiness and are sensitive to temperature changes, so that it is difficult to determine previously the opening pressure and/or opening time. From the FR-A-1.149.500 a clamping device is known for holding lining panels on walls and ceilings. This clamping device comprises a number of standing supports with broadened part and fixed on the wall or ceiling. The perimeter of each panel is fastened in a U shaped profile provided with an extension below the panel and ending in a gutter turned outwards. Between the panels and the gutter of the supports a number of leaf springs are located pressing the panels onto the supports. However, apart from the fact that it would be necessary to rebuild completely this clamping device to be suitable for holding an explosion panel on a safety opening of a holder filled with dust, gas or vapour, the clip strips must have a complicated shape to give them a spring force or bending force to retain the panel on the safety opening. Nevertheless, such clip strips do not permit a good seal between the panel and the perimeter of the safety opening, and the opening pressure and/or opening time is very difficult to determine previously. In order to remedy these disadvantages, a clamping device has been realized, as described in independent claim 1. This clamping device according to the invention, does not make use of spring strips but of clip strips having a simple shape and applying a buckling effect, by which the force to be exerted on the panel, in order to release it from the frame, can be determined very precisely by the buckling strength of the clip strips. Other advantages of this clamping device are that it is simple in construction and relatively cheap to make and that the explosion panel is easy to install. Another advantage is that the clamping device can be very precisely set to react to a predetermined very low or very high opening pressure at which it comes loose and is blown away. The opening pressure of the explosion panel can therefore be accurately determined and is measurable. Yet another advantage is that after a mild explosion the panel can be used again and only the clip strips have to be replaced. Finally the opening pressure at which the explosion panel must open can be accurately determined in advance by changing the number and characteristics of the clip strips with which the explosion panel is fixed in position. By way of example, without anyway being exhaustive, a more detailed description of a selected embodiment of the clamping device and the explosion panel is given below. This description refers to the attached drawing, in which : fig. 1 shows a front elevation of the clamping device and the explosion panel; fig. 2 shows a plan view of the same; fig. 3 shows a longitudinal section along line III-III in fig. 2; fig. 4 shows an enlarged cross-section along line IV-IV of fig. 2, in which the explosion panel closes off the safety opening of the holder; fig. 5 shows the same cross-section as in fig. 4, but when the explosion panel is being blown free during an explosion. In these figures will be seen the holder 1 which contains any dust, gas or vapour whatsoever and in which a safety opening 2 has been provided. Around this opening a perpendicular frame 3 is fastened by means of, for example, of bolts 4. On the outside of the frame there are several supporting pieces or U shaped brackets 5 at predetermined distances in which a clip strip 6 which slopes downwards and made of any material whatsoever, is fastened by means of a screw 7. The free end of each clip strip 6 engages in a retaining edge 8 preferably turned to the horizontal of the outwardly sloping sides 9 of a rigid and not heavily constructed explosion panel 10 of any material whatsoever, such as for example stainless steel, so that the explosion panel is firmly and sufficiently pressed onto the elastic seal 11 which is mounted on the perpendicular frame 3. The force necessary to make the explosion panel come free of the safety opening 2 is determined by the buckling resistance of the clip strips 6. This buckling resistance of each strip can be accurately calculated on the basis of the dimensions of the clip strip and the strength coefficient of the material from which the clip strips 6 are made. The special shape of the clip strips 6 means that they exercise a constant pressure on the explosion panel 10, so that when combined with the rigid construction of the explosion panel they ensure perfect closing of the safety opening 2 of holder 1. Of great interest is the use of the clamping device and the explosion panel according to the invention when the normal operating pressure exerted on the panel is relatively close to the opening pressure of the explosion panel, when premature or unanticipated opening of the panel is undesirable or when the panel is subject to strict operating conditions. When an explosion takes place in the holder 1, the explosion panel 10 is lifted and the stiff retaining edge 8 of the explosion panel pushes the free end of the clip strips 6 upwards (fig. 5), so that the explosion panel slides freely over the clip strips and is blown free of the safety opening 2 of the holder 1. After a mild explosion the rigid panel is usually not damaged and it is enough to replace the clip strips 6 in order to restore the device to good working order. It goes without saying that the shape, the number and dimensions of the parts described above may differ and that some of these parts may be replaced by others which have the same purpose.

Claims: Clamping device comprising a holder (1) filled with dust, gas or vapour, a safety opening (2) provided in said holder, a standing frame (3) around said safety opening (2), an explosion panel (10) with sides (9) and retaining edge (8), and clip strips (6) between said standing frame (3) and said retaining edge (8) of the explosion panel (10) for holding this panel on said frame and said safety opening, wherein one end of each clip strip (6) is fastened to the standing frame (3), the other end or free part of each clip strip (6) slopes downwards and engages in the retaining edge (8) of the explosion panel (10) to press firmly said panel (10) onto said frame (3) and said safety opening (2), whereby a supporting piece (5) is mounted on said holder (1) opposite each clip strip (6) to support the sides (9) of said panel (10), sides lying between the clip strips and the supporting pieces. Clamping device with explosion panel, according to claim 1, characterized by the fact that the explosion panel (10) is provided with at least one side which slopes outwards the free edge of which is turned horizontally inwards and forms the retaining edge (8). Clamping device with explosion panel, according to claim 1, characterized by the fact that each supporting piece consists of a U shaped bracket (5), between which bracket and the frame (3) mounted on the holder (1) the back of the clip strip (6) is fastened the free end of which slopes downwards into the U shaped bracket, between which bracket (5) and clip strip (6) the retaining edge (8) of the explosion panel (10) is held.

Inventors: JANSSENS, HENRI
Applicants: STUVEX INTERNATIONAL (NAAMLOZE VENNOOTSCHAP)
Application year: 1988
Main classification: F16B2
IPC codes: E04B1