FR2459418A1 - VACUUM TESTING FOR SHOCK PROTECTION - Google Patents

Abstract

A. VACUUM SHORING FOR GRAPHITE SLEEPING PROTECTION, SHORING CONSISTING OF A POROUS GRAPHITE DISC, PERMEABLE TO FLUIDS. B. VACUUM SHORING CHARACTERIZED IN THAT THE GRAPHITE DISC 5 HAS A POROSITY OF 15 TO 30 AND AN AVERAGE PORE DIAMETER OF AT LEAST 0.2 MM. C. THE INVENTION APPLIES IN PARTICULAR TO THE PROTECTION OF CHEMICAL TREATMENT EQUIPMENT.

Description

1. The invention relates to a shoring against vacuum

  for burst protection in graphite,

  with a porous graphite disk, permeable to fluids.

  In order to protect confined spaces, for example chemical apparatus, against a spontaneous increase in pressure within these spaces, it is known to use burst protection or bursting discs which when exceeding the permissible pressure for the container or device, tear or burst and allow, in a very short time, a pressure balance. A material particularly indicated for these bursting protections is graphite, which has a remarkable resistance to corrosion and alternating forces, which resistance is also independent of the temperature of use in the conventional temperature range for apparatus of chemistry. Another advantage of graphite burst protections is their

  breakage with a breaking character which releases suddenly and without

  later the entire section of the tube or fitting. If a depression reigns permanently, or at least momentarily

  in the receptacles to be protected, the use of special

  against vacuum is necessary or advantageous, these

  apply against the surface of the explosion protection.

  turned towards the container and preventing it from bending towards the container. These shoring against vacuum are constituted

  graphite disks having a plurality of parallel holes

  the the. These shoring against vacuum are, in general,

  mounted in such a way that they are not destroyed during the

  security by bursting and that they can be

  used later. This economically constructive achievement

  the material, also reduces the free section of

  and reduces on average about 40% the flow factor c (defined as the ratio of the effective flow to the flow in a smooth pipe, so that the cross section of the burst protection must to be increased

  compared to achievements without shoring against vacuum. The au

  alternative, which is the simultaneous destruction of vacuum shoring and burst protection, is not

  satisfactory because of the significant technical expense.

  The invention therefore relates to vacuum shoring for graphite burst protection.

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  a sheath consisting of a porous graphite disk, permeable to fluids, shoring against vacuum characterized in that the graphite disk has a porosity of 15 to 30% and a diameter

average of pores of at least 0.2 mm.

  In principle, all types of sufficiently permeable graphite are suitable, and in particular those of graphite having a porosity between 15 and 30% and an average pore diameter of at least 0.2 mm. For values below these limits, a greater pressure drop across

  the thickness of the graphite disk and thus a delay in the

  so much bursting can not be safely excluded, while above these limits, the strength of graphite

  is often not sufficient to effectively support the protection

  bursting. The coefficient of permeability of graphite must advantageously be of an order of magnitude of 101 to 105

cm2 / s.

  For the manufacture of the graphite disc,

  mored and classified in coke dimensions are

  with a pyrolitic binder, this mixture is shaped by pressing, vibrating or by another forming process,

  and the shape blank thus obtained is heated to a temperature of

  about 12000 Kelvin, for the carbonization of the binder.

  The so-called "cooked" blank is then graphitized by heating at a temperature of 3000 K, preferably in a resistance electric furnace, and then the vacuum shoring disc is made from the graphite structures thus obtained by sawing, turning, grinding, etc ... the dimensions and the number of pores can be determined during this

  process by the granulometric distribution of the coke

  the binder content and also by the speed of heating

  in the carbonization stage.

  According to another method which makes it possible to obtain graphite disks with a particularly low dispersion of the characteristics under consideration and which allows mass production of these disks, flat textile structures made of carbon fibers or of graphite, for example carbon fabrics. are stacked on top of each other, the pile is impregnated, possibly under pressure, with a pitch of coal or a synthetic resin, to then be subjected to the heat treatment described above. A composite material 2 is thus obtained.

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  which comprises, inserted into a graphite matrix, carbon fibers as reinforcing elements. If necessary, impregnation and heat treatment can be repeated

several times.

  The invention will now be explained with reference to an exemplary embodiment, not limiting, represented

  in section on the single figure attached.

  Between the flanges 1 and 1 'are clamped the bursting disc 2 made of graphite and the annular support 6, also consisting of graphited vacuum support disc 59 In the bursting disc 2 is inserted a pressure disc 3

  moving in the direction of the effort exerted, and between the disk of

  clatemert 2 or the pressure disc 3 and the disc of

  tayage against the vacuum 5, and the retaining ring 6, is disposed a graphite film 4 impermeable to gas. The porous disk 5S

  in graphite has the following characteristics: -

  Bulk density 1.58 g / cm3 Pore volume 20% Average pore diameter> 0.3 mm Flexural strength 12 N / mm2 In comparative tests it has been observed that porous graphite discs empty, do not influence the accuracy of operation of

  bursting discs and do not delay the instant bursting.

  At the time of bursting, the entire cross section of the

  bursting disc is in any case released suddenly.

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R E V E N DI AT I 0 N S

  1.- Vacuum shoring for protection by

  bursting graphite, shoring consisting of a graphite disk

  porous, permeable to fluids, shoring against the vacuum

  characterized in that the graphite disk has a porosity of

  at 30% and an average pore diameter of at least 0.2 mm.

  2. Vacuum shoring according to claim 1, characterized in that the graphite disk contains

  carbon fibers as reinforcing elements.