WO1989006921A1

WO1989006921A1 - A fireproof cabinet

Info

Publication number: WO1989006921A1
Application number: PCT/SE1988/000029
Authority: WO
Inventors: Rune Pehrsson (Deceased)
Original assignee: Pehrsson, Mikael (Legal Representative Of Pehrsson; PEHRSSON, Marléne (legal representative of PEHRSSO
Priority date: 1988-01-27
Filing date: 1988-01-27
Publication date: 1989-08-10
Also published as: SE8603339D0; SE455149B; SE8603339L

Abstract

A cabinet of essentially rectangular box-like configuration comprises walls and a ceiling and floor which are of composite construction and which comprise an outer steel plate (1), a concrete layer (2), a cellular plastic layer (3), and a board or steel-plate lining (4) in that order. Provided in at least two mutually opposing walls is a respective ventilation opening (6) which can be closed sealingly by an opening closure member (6a, 6b). The closure member (6a, 6b) is held in a given spaced relationship with its respective opening by means of a holding arrangement which in normal prevailing temperature conditions is operative to maintain the closure member in its spaced relationship with the ventilation opening but which when the ambient temperature exceeds a given level is automatically activated to cause the closure member to sealingly close its respective ventilation opening.

Description

A fireproof cabinet.

The present invention relates to a fireproof cabinet and like housings, and more specifically, although not exclu- sively, to a fireproof, or fire-resistant, cabinet for housing computer equipment, so as to protect the equipment, inclusive of both hardware and software, which may be in use or inactive, against the influence of high ambient temperatures, e.g. in the event of a fire.

It is known that computers and their associated software are likely to malfunction to a greater or lesser degree when exposed to temperatures which lie excessively above room temperature. One particularly difficult problem to resolve in this regard is that of providing protection for such computer equipment against the effect of fire and of maintaining this protection during non-working hours for example.

As is well known, the majority of minicomputers and micro¬ computers for example are housed in cabinets made of rela¬ tively thin metal sheet. Such cabinets or housings afford practically no protection against the ingress of smoke or the effect of ambient heat should a fire break out in the area in which the cabinet is placed. Software, such as magnetic storage discs, floppy discs, data recording discs comprising materials of low heat resistance, such as flat metal discs coated with magnetic material or thin plastic discs provided with a magnetizable data-storage coating, is particularly sensitive to high temperatures. When this software contains data information that has been entered during the day and processed and programmed in the computer and is required for a subsequent programme run or job run, it is essential to ensure that the software is adequately protected against damage by fire. One method of guarding against the irreversible loss of stored information through fire is to make so-called secu¬ rity copies of the magnetic storage discs at the end of the working day and to store these discs in an appropriate cabinet. This task can be extremely time consuming, how¬ ever, especially when several discs are involved. Further¬ more, there is a risk that these security discs may be forgotten or unintentionally left out of the cabinet over night, as a result of an oversight.

As beforementioned, conventional cabinets are unable to protect the contents thereof from smoke and heat.

The German published specification number 2846281 teaches a method of protecting sensitive electrical apparatus against atmospheric influences, such as abnormally high or abnormally low temperatures, by placing the apparatus in a closed box or cabinet that is lined with thermally resis¬ tant material, such as expanded polyurethane or like ex- panded plastics. The object of the invention described in this known publication, however, is to guarantee that the interior of the box will be sustained at a substantially constant temperature over a relatively long period of time. In order to achieve this there is also used a suitably di- mensioned plastic container 20 which is filled with water, which has a high thermal capacity.

The object of the present invention, on the other hand, is to provide a cabinet or like housing which is adequately insulated against, for instance, excessive ambient temper¬ atures, such as fire, and to provide a cabinet or like housing which can be maintained well ventilated, e.g. in order to provide a good working environment therein in the case of a computer cabinet, and in which the ventilation means, e.g. ventilation fans, can be switched on and off as and when desired.

Distinct from other cabinets and like housings, the inven¬ tive fireproof cabinet has a rectangular, enclosed box-like configuration with four walls, a ceiling and a floor all of which comprise composite structures. Thus, the walls, ceiling and floor of the cabinet construction each comprise an outer steel plate, a relatively thick layer of concrete bonded to the inner surface of the steel plate, a layer of heat-insulating cellular plastic bonded to the concrete layer, this cellular plastic layer enhancing the heat-pro¬ tective properties of the structure, and a covering of sheet metal or board, such as plywood, on the inner surface of the cellular plastic layer. Ventilation openings are provided in selected walls of the cabinet and means are provided for closing the ventilation openings in the event of a fire in the vicinity of the cabinet.

When the inventive cabinet is used to house computer equip- ment, it fulfills the dual purpose of enabling the heat generated by the equipment when in use to dissipate, as a result of the ventilation created in the cabinet, and to protect the contents of the cabinet against the effect of excessively high ambient temperatures and smoke. These and other characteristic features of the invention are set forth in the following claims.

In accordance with one preferred embodiment of the inven¬ tion, the ventilation openings, which are normally left open, are closed in the event of a fire with the aid of mechanically or electrically operated closure members which have a configuration similar to that of the ventilation openings. These members are conveniently held in a non- closing position under spring-bias, by means of a holding device made of a plastics material which melts or softens at a given temperature, so as to release the closure mem¬ bers, which are then urged into their respective ventila¬ tion openings under the force of the spring bias.

Alternatively, the plastic holding device of the ventila¬ tion closing system may be replaced with spring-loaded draw magnets which when energised are effective in releas¬ ing the closure members for propulsion into their respec¬ tive ventilation openings.

In accordance with a preferred embodiment of the invention, the cabinet is provided with a cable leadthrough or bushing for accommodating a single-conductor cable extending into the cabinet, said cable being insulated with a high-temper- ature silicone rubber insulation.

So that the invention will be more readily understood and further features thereof made apparent, an exemplifying em¬ bodiment of the invention will now be described with refer- ence to the accompanying schematic drawings, in which

Figure 1 is a vertical cross-sectional view of a cabinet or like housing constructed in accordance with the invention;

Figure 2 illustrates in larger scale a steel rod which is press-fitted into an outer plastic sleeve which co-acts with a closure member of the ventilation closing system and which is secured firmly in the outer steel wall of the cabinet; and

Figure 3 is a horizontal sectional view of the cabinet taken on a line which touches the upper surface of one closure member and also on a line which touches the upper surface of a further closure member. The inventive cabinet is described in the following with reference to its use for housing computer equipment. It will be understood, however, that the cabinet is not re¬ stricted to such use, but can be used to store other items and objects which are to be protected against the influence of abnormal ambient conditions and which are to be well ventilated in the course of normal ambient conditions.

Figure 1 illustrates a fireproof cabinet or like housing which is of rectangular box-like configuration and which thus comprises a roof, a floor and four walls of which one wall forms the cabinet door and the opposing wall forms the whole of the rear wall of the cabinet. The side walls S, , S- extending at right angles to the door and the rear wall of the cabinet have provided therein symmetrically tapering ventilation openings 6, which can be closed sealingly with the aid of closure members 6a, 6b in a manner hereinafter described.

These openings may have any suitable cross-sectional shape and taper symmetrically from the inner most wall surface to the outer wall surface, with the large orifice of the open¬ ing lying in the plane of the innermost wall surface.

As illustrated in the drawing, the cabinet comprises an outer shell 1 which is made of lacquered steel plate and which has a concrete lining 2 of uniform thickness bonded to the inner surface thereof. Each of the side walls S, , S_ of the cabinet has a symmetrically tapering ventilation opening 6a, 6b provided therein. The concrete linings 2 of respective walls 1 have provided thereon a coating 3 of cellular plastic, which enhances the heat-protective quali¬ ty of the composite wall construction. This coating is in turn covered with board, such as plywood, or metal sheet which forms the inwardly facing wall surface 4 of respec- tive walls. The cabinet rests on a base S.

In the case of the illustrated embodiment, the symmetrical¬ ly tapering ventilation opening in the side wall S is lo- cated immediately above the floor of the cabinet whereas the symmetrically tapering ventilation opening in the op¬ posite side wall S-. is located immediately beneath the ceiling of the cabinet. As beforementioned, the large orifices of respective ventilation openings face inwardly, towards the cabinet interior.

Each of the ventilation openings in respective side walls S- , S» can be closed either completely or partially with the aid of a correspondingly shaped closure member 6a, 6b, each of which is held in a determined relationship with its respective opening 6, such as to define a ventilation gap between the mutually opposing surfaces 8, 9 of the openings 6 and the closure members 6a, 6b, in a manner hereinafter described, and each of which is constructed from the same material layers as the cabinet walls, and in the same order as described with reference thereto.

Thus, the ventilation system of the illustrated embodiment comprises outwardly narrowing ventilation openings 6 which can be closed with the aid of correspondingly shaped clo¬ sure members 6a, 6b. As will be seen from Figure 1, each of the closure members 6a, 6b of the illustrated embodi¬ ment is held in position in relation to its respective ventilation opening 6 with the aid of a rod 10, e.g. a steel rod, one end of which is firmly embedded or grouted in its closure member 6a or 6b such as to extend co-axially with the geometric centre line of said member, and the other end of which rod is anchored to a steel angle-plate 7a, 7b, the ends of which are grouted or otherwise embedded in respective concrete linings 2 of adjacent wall struc- tures, from the inside of the cabinet, in the manner il¬ lustrated.

Each rod 10 of the illustrated ventilation closure system carries a relatively powerful thrust spring 11 which has a pre-determined spring rating and one end of which abuts an associated rigid steel plate 7a or 7b and the other end of which thrusts against the inwardly facing surface 6a', 6b' of a respective closure member 6a, 6b.

As shown schematically in Figure 1, each closure member 6a, 6b has firmly anchored in its outwardly facing narrow end a further rod 13, e.g. a steel rod, which extends co-axial¬ ly with the geometric centre line of its respective closure member 6a, 6b. The free end of each rod 13 has provided thereon a guide sleeve 12 which has a collar 14 located on one end thereof and which extends through a hole in a per¬ forated cover plate 15 firmly secured to the outer wall surface 1 of the cabinet and well covering the external orifice of the tapering ventilation opening 6, with the collar bearing against the inner surface of the cover plate 15 under the pressure exerted by the thrust spring 11. As before indicated, the cover plate 15 contains perforations to permit ambient air to pass into the cabinet. The sleeve 12 and collar 14 are made of a suitable plastics material which will be rigid and supportive at normal temperatures and which is therewith able to withstand the pressure of spring 11, but which will melt or soften at a given higher temperature, such as to collapse under the pressure of the spring.

The illustrated ventilation closure system operates in the following manner. Under normal ambient temperature condi¬ tions, e.g. ambient temperatures which are not deleterious to the contents of the cabinet, in this case computer equipment, the ventilation openings 6 are open, with re¬ spective closure members 6a, 6b held securely in a given relationship with an associated opening through the medium of plates 7a, 7b; rods 10, rods 11, sleeves 12 and cover plates 15, all of which are held rigidly during said nor¬ mal temperature conditions. On the other hand, if the ambient temperature should rise to a level which corre¬ sponds to the level at which the plastic sleeve and collar 12, 14 soften or melt, the sleeve/collar will collapse and weaken to an extent at which they are no longer able to withstand the thrust of the spring 11 and will therewith permit the closure member 6a or 6b to be driven fully home into its associated ventilation opening, therewith fully blocking said openings in sealing fashion.

Figure 3 is a horizontal cross-section view of the cabinet according to the described preferred embodiment and illus¬ trated more clearly the composite wall construction 1, 2, 3, 4 of the cabinet.

When the inventive cabinet is to be used to house computer equipment or other equipment and apparatus which requires power from an external power supply, the cabinet is pro¬ vided with leadthrough bushings herefor.

Accordingly, the cabinet illustrated in Figure 1 has two bushings 16 which lead sealingly through the side wall S„ of the cabinet at a given mutual distance apart. Each of the bushings is intended to accommodate a single-conductor cable encased in silicone rubber insulation of high-temper¬ ature resistance, such as to prevent heat from propogating from outside the cabinet to the interior thereof in the event of fire.

As shown schematically in block form in Figure 1, the il- lustrated embodiment of the cabinet has arranged on the floor thereof a drive unit 21 which includes electric power supply means (not referenced) which operate on a voltage of 220 V, a transformer for stepping down the volt- age to a level suitable for the computer equipment, and fan means (indicated in broken lines) for forced ventila¬ tion and forced dissipation of the heat generated by the computer equipment in operation. This part of the cabinet interior is partitioned off from the remainder of the cabinet, by a perforated vertical wall 22 and a perforated horizontal wall 17. The wall 17 may also be used as a support shelf for supporting a modem for example. The cabinet may also be provided with a further perforated shelf 18, for supporting hard discs, floppy discs and like magnetizable data recording media.

Although not shown the cabinet may be provided with means e.g. a thermostat, for disconnecting the supply current to the computer equipment when the temperature reaches a pre- determined value and which, in the case of large cabinets, will also activate an equipment cooling system based on electrical components of the semiconductor kind.

As beforementioned, the plastic sleeve/collar device 12, 14 may be replaced with spring-loaded draw magnets (not shown) which when energized release the closure member 6a, 6b so that said members can be propelled into their re¬ spective ventilation openings 6.

In this case the thermostat control may be arranged to co- act with an alarm system such that when the temperature rises to a pre-determined value, the thermostat activates the alarm system and the alarm system itself discontinues the supply of current to the computer system while at the same time activating an auxiliary electrical system capable of producing sufficient electrical energy to energize the spring-biassed draw magnets.

It will be understood from the aforegoing that when using a cabinet constructed in accordance with the invention there is far less risk of damage to the cabinet contents as a result of fire and, in the case of a cabinet which houses a computer, the computer may be pre-programmed to start auto¬ matically at a time when no computer personel are in atten- dance, e.g. at night without undue risk of the computer or software becoming damaged as a result of fire outside the cabinet. As a result of this security facility, the oper¬ ating times of computer systems housed in the inventive cabinet can be greatly extended.

Claims

Clai s

1. A fireproof cabinet or like housing which has an es¬ sentially rectangular, enclosed box-like configuration with four walls, a floor and a ceiling, and which is provided with ventilation openings, characterized in that the walls, ceiling and floor of the cabinet have a composite construc¬ tion, each consisting of an outer steel plate (1), a rela¬ tively thick, heat-resistance free-bearing concrete cover- ing (2) bonded to the inner surface of said outer plate, a layer (3) of insulating cellular plastic bonded to the inner surface of said concrete layer (2) said cellular plastic also enhancing the heat-protective qualities of said structure, and a smooth steel-plate or board lining (4) on the inner surface of the cellular plastic layer (3 ) ; in that each of the ventilation openings (6) is symmetri¬ cally tapering and is located in one of the cabinet walls (1, 2, 3, 4) such as to extend through the thickness of said wall with the large orifice of the ventilation opening lying in the plane of the inner surface (4) of said compo¬ site wall structure; and in that held in axial register with each ventilation opening (6) in a given relationship therewith is a spring-bias closure member (6a, 6b) which has a configuration corresponding to the configuration of the ventilation opening and which under normal temperature conditions is held under spring bias in said given rela- tionhip but which in temperature conditions in which the temperature rises above a given value is released so as to be driven into its associated ventilation opening, such as to completely seal said opening.

2. A cabinet according to claim 1, characterized in that the ventilation opening closure members (6a, 6b) comprise an outer concrete layer and an inner cellular plastic layer and have an axial extension which equals the thickness of the composite wall construction.

3. A fireproof cabinet according to Claim 1 or 2, charac¬ terized in that the holding means for holding a respective closure member (6a, 6b) in a spaced attitude relative to a ventilation opening (6) comprises a holding plate (7a, 7b) which is held firmly in parallel spaced relationship with the wall plane (4) containing the large orifice of the opening (6), a first rod means (12) which is attached at one end to the holding plate (7a, 7b), and which extends firmly into the closure member (6a, 6b) co-axially with the geometric centre line thereof, a thrust spring (11) which is carried by the rod concentrically therewith and one end of which bears against one side of the plate (7a, 7b) and the other end of which bears thrustingly against an oppos¬ ing end surface of the closure member, second rod means (13) which extends outwardly from the narrow end of the closure member co-axially with the geometric centre line of the closure member and which carries at its free end a rod guide and rod holding sleeve (12) having a collar (14) lo¬ cated at the inner extremity of the sleeve, and a perfo¬ rated cover plate (15) which is firmly attached to the outer wall surface (1) of the composite wall structure (1, 2, 3, 4) incorporating said ventilation opening and which has a hole therein whose diameter equals that of the sleeve (12), and said collar abutting the inwardly facing surface (4) of said wall (l_r 2 _r 3, 4); and in that the sleeve (12) and collar (14) are made of a material which will melt or soften at a given temperature, such that when this te per- ature is reached the sleeve and collar will collapse, thereby permitting the closure member to be driven into the ventilation opening by said spring (11).