EP0098672A2

EP0098672A2 - A fire-resistant cupboard

Info

Publication number: EP0098672A2
Application number: EP83201011A
Authority: EP
Inventors: Willem Frederik Boonstra
Original assignee: Vinitex Laboratoriuminrichtingen BV; Pielkenrood Vinitex BV
Current assignee: VINITEX LABORATORIUMINRICHTINGEN BV
Priority date: 1982-07-06
Filing date: 1983-07-06
Publication date: 1984-01-18
Also published as: NL8202704A; EP0098672A3

Abstract

A fire-resistant cupboard (1) having, at its front side (3), selfclosing folding doors (6, 7) which can be locked (8) in the open position, said locking (8) being adapted to be released by means of a temperature sensitive element (10), and provided with closing means in the form of a vertically displaceable weight (11) connected to a corresponding folding door (6, 7) by means of a cable (12), which folding door is, in particular, not provided with door closing latches, shielded means (22) being provided for relieving an internal pressure rise when the doors (6, 7) are closed, and an internal air flow along the fixed edges (25) of shelves (26) provided in the cupbaord (1) is possible. The temperature sensitive element (10) also controls a safety valve (18) in a suction aperture (16) which is directly connected to a tensioning element of said temperature sensitive element (10).

Description

For storing combustible substances in laboratories, and sometimes also for storing documents, fire-resistant cupboards are being used more and more, said cupboards consisting of fixed walls of fireproof plate material with an insulating and incombustible inner lining, and being provided, at the front side, with at least one folding door consisting of at least two panels and being hingedly connected at one side to. the fixed part of the cupboard, said door being urged by means of a closing means towards the closed position and being adapted to be retained in the open position by means of a locking bolt, said locking bolt being coupled with a tensioning element adapted to be spring-loaded and to be latched in the tensioned condition, and adapted to be released by means of a temperature sensitive actuating element as soon as the temperature outside the cupboard rises above a given value, the released tensioning element then releasing the door locking bolt.
Such a cupboard can normally be left open, the or each folding door then being hold in the open position by the locking bolt, thus facilitating placing objects in and taking objects out of the cupboard, especially if this has to be done with both hands. However, as soon as the temperature sensitive element detects an inadmissible temperature rise, the tensioning element is set free, thus releasing the locking of the door or doors, so that the latter will be closed by the closing means. The contents are, then, isolated from the environment, and, therefore, will not be able to contribute to spreading the fire. The walls should be sufficiently insulating for preventing a substantial temperature rise inside the cupboard within the prescribed time (which should be sufficient for allowing the present personnel to flee), so as to avoid, or at least to defer as long as possible, an explosion of the contentso All this can still be improved by providing in the door joints material swelling on being heated, so that, in the case of fire, hot air or gases are prevented from penetrating into the cupboard.
In the current cupboards of this kind springs are provided in the door hinges which are tensioned when opening the door in question, and, moreover, the door is provided, in particular near the hinges between two panels, with door latches, for keeping the door in the closed position. If the door is closed as a consequence of a temperature rise, the spring loaded door latches should be allowed to snap in the locking position when reaching the closed position of the door, said bolts serving for keeping the doors closed also at an internal rise of pressure. In order to ensure this snapping action under all circumstances, the final velocity of the door during closing should be high, and thus the closing spring tension in the open position should be accordingly high. This makes difficult the opening of the door against the gradually increasing spring force, and the fast closing of the door with a heavy blow can be dangerous for people standing in the neighbourhood, also if the door has to be closed under normal conditions.
The invention provides an improved cupboard of this kind, which is characterised in that the closing means for a folding door is formed by a vertically displaceable weight which is coupled with the folding door by means of a cable guided by means of rollers, said folding door being, in particular, not provided with a latch, and, the closing weight being sufficiently heavy for keeping the folding door closed.
Such a weight provides a constant closing force, and opening can take place against a constant force which is considerably easier. If the door is constructed without a door latch, the closing velocity should not be high so that a relatively light weight will be sufficient. Door latches allow, indeed, a certain internal overpressure, but this can lead to a general deformation of the cupboard. It has appeared to be more favourable to provide, in an isolated part of the cupboard and in particular-in the rear wall, a venting aperture which allows, under normal conditions, venting the contents of the cupboard by means of air sucked in, and which is not closed in the case of fire so that the pressure rise inside the cupboard caused by the rising temperature is directly released through this aperture, and no pressure will be exerted on the unlatched doors.
Isolating said venting aperture is preferably obtained by extending the lateral walls beyond the rear wall, so that, together with a wall of the building against which the cupboard is placed, an air duct is formed which is protected against direct fire action. Said wall extensions are, in particular, formed by channels in which the door closing weights are arrangVdY
An other draw-back of the current folding doors is that they are guided at the upper as well as at the lower side in U-channels which, at the same time, are intended to be engaged by the door latches. The lower channel can, however, easily get soiled which will impede the closing of the doors. According to the invention the door is, preferably, not guided at all at the lower side, which is made possible by the absence of door latches, Preferably a fixed claw is provided at the lower side, behind which a pin mounted near the front edge can grip when approaching the closed position, so as to retain the door outwards in the closed condition, thus counteracting rattling and providing a certain counter pressure when sealing strips swelling or foaming on being heated come into action.
Laboratory cupboards are, generally, connected to a suction duct so as to allow to remove vapours present in the cupboard, in which duct a security valve can be provided which suppresses the suction at a temperature rise, so that, when the door or doors are closed in the case of fire, no negative pressure will occur inside the cupboard. In the cupboard according to the invention, this security valve is preferably constructed as a drop valve which is directly coupled with the tensioning element of the door retaining locking bolts and is kept open in the tensioned condition thereof, which allows a simple and dependable construction.
For opening the door, generally a handle is mounted near the hinge connection between two door panels. With the current cupboards there is a risk that fingers get jammed between these panels, and always one hand is necessary for actuating the door latch. so that only one hand is free for pulling at a door handle. With a cupboard according to the invention the handle is preferably constructed as a continuous bar situated at a distance of the panel in question, which, because of the absence of a door latch, can be held, if necessary, by two hands, and can be situated at such a distance from the door panels that there is no risk that fingers get between the door panels.
In order to allow to arrange shelves in a simple manner in the cupboard, and nevertheless to maintain a sufficient upward ventilation flow, it is advisable to use mounting stiles for these shelves extending so far from the adjacent wall that, between the near-by edges of shelves and the adjacent wall, a ventilation gap remains free.
The invention will be elucidated below in more detail by reference to a drawing, showing in:

Fig. 1 a diagrammatic representation in perspective of a cupboard of the invention;
Fig. 2 a diagrammatic cross-section of the suction duct connection of this cupboard with a security valve arranged therein; and
Fig. 3 a partial view in perspective of mounting stiles for shelves for such a cupboard.

The cupboard sLown in the drawing comprises fixed walls, namely lateral walls 1, an upper wall 2, a bottom wall 3 and a rear wall 4, the front side being open and adapted to be closed by means of two folding doors each consisting of two panels 5 and 6, the panels 5 being connected to the fixed cupboard parts by means of hinges 7. Near their free terminal edges the panels 6 are, at their upper sides, guided in the usual manner in a guiding channel (not shown), but at their lower sides no guiding means are present.
As usual in such cupboards, locking means diagrammatically shown at 8 are provided which retain the doors in the open position, and which are kept active by means of a spring loaded tensioning means with a tensioning handle 9 until the tensioning means is released by means of a heat sensitive element 10.
The doors are each urged towards the closed position by means of an associated weight 11 which is connected to the door by means of a cable 13 guided by guiding rollers 12. The cable 13 can, for instance, be fixed to a free terminal edge of a door panel, but it is also possible to lead this cable over a pulley connected to the hinge axis 7.
When the locking bolts 8 are released, the doors are closed under the influence of the weights 11. At the lower side of each panel 6 and near its free terminal edge a pin 14 is provided which, when approaching the closed position, can grip behind a claw 15, so that this terminal edge in the closed position will be retained against outward forces also at the lower side.
In the upper wall 2 an air suction connection 16 is provided which is represented in section on a larger scale in Fig. 2, which connection is intended to be connected to a suction duct provided with a blower, and communicates via an aperture 17 with the interior of the cupboard. The aperture 17 can be closed by means of a drop valve 18, which valve is provided with an eye 19 into which an arm 20 is inserted which is directly fixed to a rod 21 to which the tensioning handle 9 is connected. As soon as the spring loaded tensioning element connected to this handle 9 has been tensioned by means of this handle, the valve 18 is lifted. When the tensioning means is unlatched by a temperature rise, the rod 21 is rotated so that the valve 18 is closed.
In order to allow a ventilation in the cupboard with the doors closed under normal conditions, an air suction aperture 22 is provided in the rear wall 4 near the lower side thereof. This aperture can also divert outwards possible pressure rises inside the cupboard. In order to avoid that, in the case of fire, flames or hot gases will penetrate inwards through this aperture 22, the latter is isolated in that the lateral walls 1 extend beyond the rear wall 4, so that, together with the wall of the building against which the cupboard is placed, a protected air duct is defined. Also in the case of two cupboards placed with their rear walls against one another such a duct can be obtained. These extending parts of the lateral walls 1 are, in particular, formed by channels 23, in each of which a weight 11 is received so that, for these weights, no interior cupboard space is required.
In such cupboards generally shelves are provided, but the latter can impede the inner ventilation. Therefore the shelves are, preferably, supported in the manner of Fig. 3 by means of stiles 24 which are situated at some distance from the adjacent wall, so that a passage 25 next to the shelve 26 fixed thereto remains free.
As shown in Fig. 1, the door panels 5 are provided with a handle bar 27 extending over a substantial part of the height of the panel in question, and serving for pulling the door open. This handle bar is situated at some distance from the panel, thus avoiding that fingers can get jammed in the joints between the panels 5 and 6 if the door would suddenly close again. Such a handle bar can be easily gripped by two hands, irrespective of the height of the person in question.
Since the closing weights 11 exert a constant pulling force on the associated door, the pulling force to be exerted on the handle bar 27 when opening the door further will not substantially increase, which facilitates the opening. A constant torque can be obtained by connecting the cables 13 to a pulley connected to the door hinge in question.

Claims

1. A fire-resistant cupboard with fixed walls made of plate material with an insulating and incombustible inner coating, and with, at the front side, at least one folding door consisting of at least two panels and connected at one side to the fixed cupboard part by means of hinges, which door is urged towards the closed position by a closing means, and can be retained in the open position by a retaining locking bolt, the latter being coupled with a spring loaded tensioning element, the latter being adapted to be latched, in the tensioned condition and to be released by means of a temperature sensitive actuating element as soon as the temperature outside the cupboard rises above a given value, the released tensioning element releasing the door locking bolt, characterised in that the closing means for a folding door is formed by a vertically displaceable weight which is coupled with the folding door by means of a cable guided by rollers.

2. The cupboard of claim 1, characterised in that the folding door is not provided with door closing latches and in that the closing weight is sufficiently heavy for keeping the folding door closed.

3. The cupboard of claim 1 or 2 with an air suction opening, characterised in that the air suction opening is provided at the lower side in the rear wall, and in that the lateral walls of the cupboard are extended beyond the rear wall in order to define an air supply duct which is laterally isolated as soon as the cupboard is placed against a wall.

4. The cupboard of claim 3, characterised in that the lateral wall extensions are formed by channels receiving a closing weight.

5. The cupboard of any one of claims 1..4, characterised in that the outer panel is guided near its free terminal edge only at its upper side in an open channel.

6. The cupboard of claim 5, characterised in that the folding door near its free terminal edge and at its lower side is provided with a pin which, when approaching the closed position, can grip behind a fixed claw which can keep the end panel at the lower side in the closed condition.

7. The cupboard of any one of claims 1..6, having a suction aperture in the upper wall provided with a security valve adapted to be closed at a temperature rise, characterised in that the security valve for the suction aperture is a drop valve which is directly coupled with the tensioning element by means of a bell crank in such a manner that the valve is open in the tensioned condition of said element.

8. The cupboard of any one of claims 1..7, in which the inner panel of a folding door near its hinge connection with the outer panel is provided with a handle for opening the folding door, characterised in that this handle is in the form of a continuous bar situated at some distance from this panel.

9. The cupboard of any one of claims 1..8, provided with shelves to be fixed on vertical stiles, characterised in that these stiles protrude in respect of the adjacent wall so as to leave free a ventilation passage between the nearby border of a shelve and the adjacent wall.