GB1586577A

GB1586577A - Ventilators

Info

Publication number: GB1586577A
Application number: GB32884/77A
Authority: GB
Original assignee: Colt International Ltd
Current assignee: Colt International Ltd
Priority date: 1976-08-05
Filing date: 1977-08-05
Publication date: 1981-03-18
Also published as: AT386124B; AU2762377A; DE2635248A1; ATA578077A; FR2360799A1; BE857553A; NL7708527A; DE2635248C2; FR2360799B3; CH626708A5

Abstract

The device has at least one flap which is mounted pivotably over a ventilation opening which is to be closed. This flap can be actuated by a pneumatic-spring arrangement (1) which has a cylinder (10) filled with compressed gas, a piston (15) which is movable in this cylinder (10) and a piston rod (16) connected to the piston (15). In order to tension or release the pneumatic-spring arrangement (1) without subjecting the flap to additional twisting forces, a further piston (5) is provided, which is movable in a further cylinder (2). An inlet (7', 9) for the supply of compressed air opens into the further cylinder (2). The first-mentioned cylinder is connected to the further piston (5) or the further cylinder (2) while the first-mentioned piston (15) is connected to the further cylinder (2) or the further piston, the whole in such a manner that the pneumatic-spring arrangement (1) can, under the action of said compressed air, be extended from a retracted position, in which the flap is closed, into an extended position, in which the flap is open. As a result, there is a greater opening force which remains practically constant over the opening travel. <IMAGE>

Description

PATENTS ACT 1949 SPECIFICATION NO 1586577 The following amendments were allowed under Section 29 on 19 June 1986 Page 1 Line 52 Delete a further insert an Page 1 Line 66 Delete one of said members insert said piston member Page 1 Line 67 Delete the other of said me-insert said cylinder member Page 1 Line 68 Delete bers Page 3 Line 26 Delete one of said insert said piston Page 3 Line 27 Delete members insert member Delete the Page 3 Line 28 Delete other of said members insert said cylinder member Page 3 Delete Lines 35 and 36 insert said cylinder member and said first cylinder extends THE PATENT OFFICE 2 September 1986 -.......Lianuapuninsaiacytmcter member for the supply of pressurised fluid thereto, said cylinder being fixed to one of said members and said piston being fixed to the other of said members whereby the device is extensible, under the influence of said gas from a telescoped configuration in which the piston rod is located within said first cylinder and the flap is closed, to open the flap.

2. A ventilator as claimed in claim 1, in which said piston rod is secured to one end of said cylinder member and said cylinder is secured to said piston member and extends through the other end of the cylinder member, attachment points being provided at said one end of the cylinder member and at the outer end of said first cylinder.

3. A ventilator as claimed in claim 2 in spring device and close the flap in the absence of fluid under pressure supplied through said port and acting in the space within the cylinder member.

7. A ventilator as claimed in claim 6 including fusible link means in series with said spring means and rendering said spring means inoperative in the event of a fire thereby allowing said gas spring device to open the flap.

8. A ventilator substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

(54) IMPROVEMENTS RELATING TO VENTILATORS (71) We, COLT INTERNATIONAL LIMITED, a British company of New Lane, Havant, Hampshire P09 2LY, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement :- The present invention relates to ventilators and is particularly concerned with a mechanism for opening and closing, in particular, a fire ventilator flap.

Fire ventilators whose ventilating flap or Saps provide, in the event of a fire, openings in the roof of a building for the escape of fumes and heat, are well known and it has been proposed to use gas-pressure springs for opening the ventilating flaps. Gas-pressure springs, while being of small construction, make available, by means of a gas filling subjected to pressure, high thrust forces such as are re quired for a reliable opening of the ventilating flap particularly in cases where the ventilating flap is loaded, for example by snow and/or wind pressure.

The closing of a ventilating flap against the continuing action of the gas-pressure spring necessitates high closing forces which, in many cases, cannot be applied or can be applied only with dimculty by hand. It is indeed possible to provide, in parallel with, and adjacent to, the gas-pressure spring effecting the opening of the ventilating flap, a fluid cylinder on whose piston the fluid will act for an operating movement that is opposed to the direction of the gas-pressure spring thrust, so as to close the ventilating flap. However, such a parallel installation of a flmd cylinder in addition to a gas-pressure spring necessitates a considerable constructional expenditure and is operationally unfavourable because separate points of action have to be provided, both for the gas-pressure spring and for the fluid cylinder, on the ventilating flap, on the one hand, and for example on the fire ventilator frame, on the other hand. Furthermore, special provisions have to be made for absorbing, without any deformation, the twisting moments which occur between the respective points of action in the area of the ventilating flap and the ventilator frame or other support.

It is a further object of the present invention to provide a ventilator actuating mechanism incorporating a gas-pressure spring device which obviates or mitigates these difficulties.

The present invention is a ventilator comprising a flap hinged to close over an aperture and actuable by a gas spring device comprising a first cylinder filled with gas under pressure, a piston movable in said first cylinder, a piston rod connected to said piston, a piston member movable in a cylinder member and a port in said cylinder member for the supply of pressurised fluid thereto, said first cylinder being fixed to one of said members and said piston being fixed to the other of said members whereby the device is extensible, under the influence of said gas from a telescoped configuration in which the piston rod is located within said first cylinder and the flap is closed, to open the flap.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in whict :- Fig. 1 is an axial section of a gas-pressure spring device; and Fig. 2 is a diagrammatic side elevation of a ventilator and its actuating mechanism according to the present invention incorporating gas pressure spring devices as shown in Fig. 1.

The device 1 shown in Fig. I comprises a cylinder 2 closed at the top by a head plate 3 and at the bottom by a base plate 4. A substantially plate-shaped piston 5, which carries on its circumference a seal 6 so as to seal the piston from the internal wall of the cylinder 2, is axially displaceable within the cylinder 2.

The cylinder chamber 7 located above the piston 5 is connectible, via a connection bore 7'in the head plate 3, to a source of pressurised fluid, in this embodiment a compressed air source, by means of which compressed air, of e. g. 7 bar, can be applied to the piston.

Compressed air sources of this character are generally available in every industrial establishment. The space 8 beneath the piston 5 con nects to atmosphere via a ventilating port 9 in the base plate 4 of the cylinder 2.

The piston rod of the cylinder 2 is formed by the cylinder 10 of a gas-pressure spring 11, whose closed or outer end forms the free connection end of the piston rod. The cylinder 10, which is axially displaceable in a coaxial bore 12 of the head plate 3 and is sealed by a seal 13, is provided with a gas filling 14, which is subjected to a very high pressure, and is secured near its inner end, to the piston 5, the inner end of the cylinder 10 of the gas-pressure spring 11 passing through the piston 5 to the underside thereof which is remote from the pressure side. The piston 15 in the cylinder 10 is seated at the upper end of a piston rod 16 which coaxially passes through a seal 17 at the internal end of the cylinder 10 of the gaspressure spring. The lower end of this piston rod is secured to the base plate 4 of the cylinder 2, in this embodiment, by being screwed into a blind tapped hole in the base plate 4 by means of a thread lug. The piston rod 16 of the gas-pressure spring 11 thus guides the cylinder 10 of the gas-pressure spring 11 in a movement through the head plate 3 of the cylinder 2.

Attachment points for the device are provided at 18, the free end of the cylinder 10, and at 19, on the base plate 4.

When the cylinder chamber 7 of the cylinder 2 is not under pressure the cylinder tube 10 of the gas-pressure spring 11 is pushed out wardly from the cylinder 2 under the action of the pressure exerted by the gas filling 14 until the piston 15 abuts the seal 17 and pre vents any further upward movement. When the compressed air now acts in the cylinder chamber 7 via the connection bore 7', the piston 5 moves downwards in the direction of the base plate 4 of the cylinder 2 and carries with it the cylinder 10 of the gas-pressure spring 11, which moves past the stationary piston 15 of the gas-pressure spring 11.

It goes without saying that the effective pressure surface of the piston 5 in relation to the effective pressure surface of the piston 15 is such that the pulling or closing force of the cylinder 2 caused by the pressure of the com pressed air is greater than the thrust force of the gas pressure spring 11, which is determined by the pressure of the gas filling 14 in the cylinder 10.

It can thus be seen that the device illustrated in Fig. 1 moves to its retracted or telescoped configuration when the pressurised fluid is sup plied to the cylinder chamber 7, and moves to its extended configuration when the chamber 7 is de-pressurised.

In Fig. 2 is illustrated a ventilator having two identical mechanisms for opening and closing respective ones of a pair of ventilator flaps, 26 and 27, which close apertures at the top of a rectangular housing 21 having walls 22 and 23 around an opening 24 in a roof 25.

Across the centre of the housing 21 is provided a trough-shaped member 28 against which the free ends of the flaps abut. As the mechanisms are identical the following description is directed primarily to the mechanism associated with the flap 26.

The flap 26 is secured to a hinge member 34 which is pivotally mounted at 33 on a support bracket 36 secured to the wall 22. Also extending between the bracket 36 and the flap 26 is a gas-pressure spring device 1 as previously described in relation to Fig. 1, but it should be noted that the free end of the cylinder 10 is secured at 37 to the bracket 36 and the base plate 4 is secured to the flap 26 i. e. when compressed air is supplied to the device 1 it retracts to close the flap 26 and when the compressed air supply is removed the device 1 extends to open the flap 26.

It should, of course, be understood that while one device 1 is shown associated with the one flap 26, several devices 1 could be used in parallel to open a long flap or indeed a single device 1 could be used to open several linked ventilator flaps.

Thus, a satisfactory mechanism for opening and closing a ventilator flap has been described but it is desirable to guard against inadvertent opening of the ventilator flap caused by failure of the compressed air supply to the device 1, and for this purpose a locking mechanism is provided.

The locking mechanism consists of a latch 46 which co-operates with a catch 38 to hold down the flap 26 in the event of a failure in the compressed air supply to the device 1.

The catch 38 is pivotally mounted on the flap 26 and is spring biased to the catch engagingposition. The latch 46 is movable by means of a cylinder 52 in this embodiment a pneumatic cylinder from the extended catch engaging position illustrated to a retracted catch releasing position (of latch 46'for the flap 27). The latch 46 is provided with an inclined upper surface at its catch engaging end to allow the flap to close when the latch is in its catch engaging position, the inclined surface causing the downwardly moving catch to pivot against its spring bias and thus clear the latch, the spring bias then moving the catch beneath the extended latch.

The air supply to the cylinder 52 may be independent of the main supply to the device 1, or it may be the same supply used to retract the latch 46 against a spring bias, either system ensuring that the Sap 26 does not open in the event that compressed air is not supplied to the device 1.

To vent smoke and fumes it is desirable that the ventilator flap opens automatically in the event of fire and this is achieved by including in the catch 38 a fusible link element which renders the locking mechanism inopera tive in the event of fire. A similar fusible plug in the main air line to the device 1 ensures that the flap is not held down by the device 1.

Reverting to Fig. 1, it is clear that if a supply of compressed air is connected to the port 9, with the chamber 7 exhausting to atmosphere, then the compressed air acts on the piston 5 to extend the device 1.

The device 1 connected in this way may be used in the ventilator system in parallel with a spring of sufficient strength to overcome the gas-pressure spring to close the ventilator flap, the supply of compressed air then causing the ventilator flap to open. A fusible link in series with the parallel spring then provides the automatic fire opening facility.

Claims

WHAT WE CLAIM IS :-

1. A ventilator comprising a flap hinged to close over an aperture and actuable by a gas spring device comprising a first cylinder filled with gas under pressure, a piston movable in said first cylinder, a piston rod connected to said piston, a piston member movable in a cylinder member and a port in said cylinder member for the supply of pressurised fluid thereto, said cylinder being fixed to one of said members and said piston being fixed to the other of said members whereby the device is extensible, under the influence of said gas from a telescoped configuration in which the piston rod is located within said first cylinder and the flap is closed, to open the flap.

3. A ventilator as claimed in claim 2 in which said port communicates with the space within said cylinder member surrounding said cylinder whereby pressurised fluid supplied to the port causes the device to assume its telescoped configuration and close the flap.

4. A ventilator as claimed in any preceding claim including a locking mechanism comprising a catch secured to the flap and a latch movable to engage the catch when the flap is closed over the aperture.

5. A ventilator as claimed in claim 4 in which the locking mechanism includes a fusible element rendering it inoperative in the event of a fire.

6. A ventilator as claimed in claim 2 in which said port communicates with the space within said cylinder member surrounding said piston rod whereby pressurised fluid supplied to the port causes the device to assume its extended configuration to open the flap, there being spring means in parallel with said gas spring device and acting upon said flap in the sense to close the flap, said spring means being of sufncient strength to overcome the gas spring device and close the flap in the absence of fluid under pressure supplied through said port and acting in the space within the cylinder member.