GB2151013A

GB2151013A - Dampers for ventilation ducts

Info

Publication number: GB2151013A
Application number: GB08430877A
Authority: GB
Inventors: Neville Preston
Original assignee: HASLAM GEORGE GILBERT
Current assignee: HASLAM GEORGE GILBERT
Priority date: 1983-12-07
Filing date: 1984-12-06
Publication date: 1985-07-10
Also published as: EP0154089A2; DE3477508D1; GB8332651D0; GB2151013B; GB8430877D0; EP0154089B1; EP0154089A3

Abstract

Damper blades 12 are each mounted on a shaft 14 provided with a pinion 16 which engages a linearly movable toothed rack 22. When smoke or a high temperature is detected, an electrical heating element 60 heats wax in a cylinder 58 to move a piston 56. The piston displaces a cylinder 48 against the action of a spring 52 so that a pin 46, engaged in a spiral groove 44, rotates a shaft 40. A pinion 38 secured to the shaft displaces the rack 22 thereby rotating each of the pinions 16 to close the blades. Adjacent blades may move in the same or opposite directions. A detent may lock the blades in a closed position until it is manually reset. <IMAGE>

Description

1 GB 2 151 013A 1

SPECIFICATION

An improved control apparatus This invention relates to control apparatus such as fire dampers or duct dampers and more particularly to fire dampers or duct dampers provided with movable blades for controlling the flow of air or other gases there- through.

Such fire dampers or duct dampers having movable blades are usually adapted to be mounted in ventilation ducts or ventilation apertures in, for example, walls and move- ment of the blades between an open and closed position enables the flow of air or other gases through the fire damper or duct damper to be controlled. It is also known to provide means for closing the blades in the event of a fire to prevent smoke or noxious fumes passing therethrough in order, for example, to restrict or to avoid the spread of smoke or fumes through the ventilation ducting of a building.

In one known type of fire damper or duct damper having movable blades, the blades are pivotally mounted in a housing and extend transversely thereof. The blades are drivably interconnected by a train of gears so that the blades pivot in unison. However, this known type of fire damper suffers from the disadvan tages that utilisation of a train of gears as the drivable interconnection between the blades requires major alterations to be made to the gear train in order to provide alternative paral- 100 lel to opposed blade movement. In this con text, parallel blade movement consists of movement of adjacent blades in the same direction of rotation about their pivotal axes and opposed blade movement consists of 105 movement of adjacent blades in opposite di rections of rotation.

In addition, the utilisation of a drivable interconnection in the form of a train of gears results in an operating member controlling movement and positioning of the blades hav ing a rotary movement which makes it difficult to accurately control the positioning of the operating member and thus the positioning of the blades drivably connected thereto, and the object of this invention is to provide control apparatus such as a fire damper or duct damper in which the above disadvantages are wholly or partly alleviated.

According to this invention, control appara- 120 tus comprises a housing having two or more blades pivotally mounted therein and extending transversely thereof, and operating means drivably interconnected to the blades to pro- duce pivotal movement of the blades in unison, wherein the operating means includes an operating member which is linearly movable.

Preferably, the operating means comprises gear pinions mounted on the blades which drivably engage the gear teeth of a rack formed on the operating member.

Preferably, also, each gear pinion is disposed in an aperture formed in the operating member and the gear teeth of the rack which drivably engage the pinion are formed on one side of the aperture.

Each pinion is, preferably, provided with gear teeth on only a part of the circumference thereof and the remaining portion of the cir- cumference is a close fit with the other side of the aperture to retain the gear teeth on the pinion in engagement with the gear teeth of the rack.

Preferably, the gear teeth of the rack which engage the gear pinion associated with one blade are disposed on the opposite side of the aperture in the operating member to the gear teeth of the rack which engage the gear pinion associated with the adjacent blade so that adjacent blades move in opposite directions of rotation.

Alternatively, the gear teeth of the rack which engage the gear pinion associated with one blade may be disposed on the same side of the aperture in the operating member to the gear teeth of the rack which engage the gear pinion associated with the adjacent blade so that adjacent blades move in the same directions of rotation.

Preferably, the pivotal axes of the blades are disposed in a single plane and the operat ing member is slidably mounted in the hous ing for linear movement in a direction parallel to said single plane.

Preferably, also, resilient means is provided for urging the blades towards a closed posi tion in which adjacent blades are aligned in touching contact with each other. The resilient means, preferably, comprises one or more springs extending between the operating member and the housing.

Alternatively, automatic closure means is drivably connected to the operating member via a rack and pinion drive for automatically urging the blades towards their closed position. The automatic closure means, preferably, includes a smoke or heat detector which initiates closing movement of the blades when the presence of smoke or excessive heat is detected.

Preferably, an operating handle is connected to the operating member to enable the position of the blades to be manually controlled.

Alternatively, a power-operated actuator is connected to the operating member to control the position of the blades.

Preferably, also, adjustable stop means associated with the operating member is pro- vided to enable the position, such as the closed position, of the blades to be adjusted.

Switch means associated with and operated by movement of the operating member relatively to the housing is, preferably, provided for enabling an indication of the position of 2 GB 2151 013A 2 the blades to be obtained.

A preferred embodiment of this invention will now be described, by way of example only, with reference to the accompanying drawings of which:

Figure 1 is a partly sectioned front elevation of a fire damper or duct damper with parts omitted for the sake of clarity; Figure 2 is a side elevation of the fire damper or duct damper with parts omitted for 75 the sake of clarity; Figure 3 is a side elevation of the fire damper or duct damper showing a manual operating mechanism; Figure 4 is a side elevation of the fire 80 damper or duct damper showing an adjustable stop means; Figure 5 is a side elevation of the fire damper or duct damper showing a blade position indicating means; Figure 6 is a section on the fine VIM in Figure 1 of the drawings; and Figure 7 is a partly sectioned side elevation of a lock-out mechanism of the fire damper or duct damper.

Referring now to the drawings, a fire dam per or duct damper which is adapted to be mounted in ventilation ducts or ventilation apertures in walls of buildings comprises a substantiailly rectangular housing 10 having four blades 12 extending transversely thereof.

Each blade 12 is provided with an integral central shaft 14 which is journalled at its ends in the sides of the housing 10 so that the blades 12 are pivotally movable relatively to the housing 10 between an open position (not shown) in which the blades 12 extend perpen dicularly to the plane of the housing 10 and a closed position (shown in Figure 1 of the drawings) in which the blades 12 extend parallel to the plane of the housing 10 and engage in touching contact to prevent or restrict the passage of smoke or noxious gases through the housing 10 and the ducting or aperture (not shown) in which the fire damper 110 or duct damper is mounted.

A gear pinion 16 is secured on the portion of each shaft 14 which projects from one side of the housing 10 and the pinion 16 is provided with gear teeth on part of the cir cumference thereof which teeth mesh with the gear teeth of a rack 18 formed on a side of an associated elongate substantially rectangular aperture 20 in an operating member 22. The portion of the circumference of each gear pinion 16 which is provided with gear teeth is arranged to be sufficient to effect pivotal movement of the associated blade 12 be tween the open and closed position. The remaining portion of the circumference of each pinion 16 is a close fit with the other side of the aperture 20 to retain the gear teeth on the pinion 16 in engagement with the gear teeth of the rack 18. The operating member 11 is slidably mounted in guides 24 130 formed on the housing 10 and is constrained to move linearly in a direction parallel to a plane containing the pivotal axes of the blades 12.

The portion of the circumference of each pinion 16 which is devoid of gear teeth and which is a close fit with said other side of the associated aperture 20 in the operating mem ber 22 can also be provided with a groove in which the operating member 22 is a sliding fit. Such grooves in the pinion 16 constitute guides for the operating member 22 and can be used to replace the guides 24.

The provision of the racks 18 on opposite sides of adjacent apertures 20 results in movement of the operating member 22 pro ducing rotation of adjacent blades 12 in oppo site directions, as shown in the drawings.

However, it will be appreciated that if the operating member 22 is replaced by a similar operating member in which the racks are provided on the same sides of adjacent aper tures, adjacent blades 12 will rotate in the same direction when the operating member is moved relatively to the housing 10.

Referring now particularly to Figure 3 of the drawings, two helical tension springs 26 are connected between mounting points on the operating member 22 and the housing 10 so as to urge the operating member 22 so that the blades 12 are urged towards their closed position in which they are aligned in touching contact with each other to prevent or restrict the flow of smoke or gases through the hous- ing 10. An operating handle 28 is pivotally mounted on the housing 10 and is located between two pins 30 mounted on the operating member 22 so that movement of the handle 28 produces corresponding movement of the operating member 22 against the action of the springs 26 to rotate the blades 12 to an open position (not shown).

Referring now particularly to Figure 4 of the drawings, where a fire damper or duct damper is to be utilised as a balancing damper controlling the flow of air through, for example, ventilation ducting, the operating member 22 is provided with a stop 32 extending from one side thereof. An adjustable screw jack 34 is mounted on the housing 10 so as to engage the stop 32 and provide a positive limit to movement of the operating member 22. It will be appreciated that this stop 32 and screw jack 34 enable not only the closed position of the blades 12 to be determined but also enable the closing of the blades 12 to be preset at any desired position so as to allow a predetermined volume of air flow therethrough.

Further adjustable screw jacks 24 and where required additional associated stops 32 can be provided to form adjustable limits to enable the open position of the blades 12 to be adjusted.

Referring now to Figure 5 of the drawings, 3 GB 2 151 013A 3 the same stop 32 or a similar stop can be utilised to actuate two micro switches 36 mounted on the housing 10 so that a remote visual indication of the position of the blades can be obtained so that it can easily be determined whether the blades 12 are, for example, in their open or closed position.

Referring now particularly to Figures 1, 2, 6, and 7 of the drawings, the aperture 20 at the lower end of the operating member 22 is 75 of extended length and the rack 18 formed on the side thereof is also of extended length and engages in mesh with a further pinion 38 mounted on a shaft 40 journalled in an exten- sion 42 of the housing 10. The shaft 40 is constrained against endwise movement by means of two circlips 43 disposed on each side of the extension 42. The shaft 40 is also provided with a spiral groove 44 and a pin 46 is adapted to engage in the groove so that sliding movement of the pin 46 produces rotation of the shaft 40, the pinion 38 and movement of the operating member 22 and the blades 12 in the housing 10.

The pin 46 is mounted in a cylinder 48 which is slidable in the bore of a boss 50 of the extension 42. A helical compression spring 52 is confined endwise between the boss 50 and an enlarged diameter portion 54 of the cylinder 48. The end face of the enlarged diameter portion 54 of the cylinder 48 is engaged by a piston 56 extending from a cylinder 58 containing wax and an electrical heating element 60 is wound around the external surface of the cylinder 58.

In operation, when a smoke detection device (not shown) detects the presence of smoke or a temperature sensing device (not shown) detects excessive heat indicating a fire, the electrical heating element 60 heats the wax in the cylinder 58 and moves the piston 56 towards the pinion 38. The cylinder 48 is thus moved against the action of the spring 52 towards the pinion 38 and the movement of the pin 46 in the spiral groove 44 produces rotation of the shaft 40 urging the blades 12 towards their closed position. If the smoke or excessive heat detected do not persist, and the signal to the electrical heating element 16 is removed, the piston 56 retracts into the cylinder 58 under the action of the spring 52 and the corresponding movement of the pin 46 in the spiral groove 44 produces rotation of the shaft 40 to return the blades 12 to their open position.

until the spring loaded plunger is manually withdrawn to reset the automatic closure means.

It will be appreciated that the linear move- ment of the operating member 22 of the above described fire damper or duct damper in combination with the utilisation of rack and pinion drives for the blades facilitates the production of a fire damper or duct damper in which the positioning of the blades can be accurately _controlled utilising relatively simple adjustable stops mounted on the housing 10 and operating member 22. In addition, it will be appreciated that the alternatives of parallel or opposed blade movement can be readily provided in a fire damper or duct damper having a basically standard configuration by merely changing the type of operating member 22 utilised in the fire damper.

In a modification, the operating member 22 is connected to a linear actuator (not shown) mounted on the housing 10 which effects sliding movement of the operating member 22 to open and close the blades of the fire damper or duct damper or to adjust the position thereof.

Claims

1. Control apparatus comprising a housing having two or more blades pivotally mounted therein and extending transversely thereof, and operating means drivably interconnected to the blades to produce pivotal movement of the blades in unison, wherein the operating means includes an operating member which is linearly movable.

2. Control apparatus according to Claim 1, wherein the operating means comprises gear pinions mounted on the blades which drivably engage the gear teeth of a rack formed on the operating member.

3. Control apparatus according to Claim 2, wherein each gear pinion is disposed in an aperture formed in the operating member and the gear teeth of the rack which drivable engage the pinion are formed on one side of the aperture.

4. Control apparatus according to Claim 3, wherein each pinion is provided with gear teeth on only a part of the circumference thereof and the remaining portion of the circumference is a close fit with the other side of the aperture to retain the gear teeth of the pinion in engagement with the gear teeth of the rack.

However, referring now to Figure 7 of the

5. Control apparatus according to any one drawings once the blades 12 have reached of Claims 2 to 4, wherein the gear teeth of their fully closed position due to operation of the rack which engage the gear pinion associ the above described automatic closure means, ated with one blade are disposed an the a spring loaded plunger indicated generally at 125 opposite side of the aperture in the operating 62 mounted in the boss 50 of the extension member to the gear teeth of the rack which 42 extends through an aperture in the cylinengage the gear pinion associated with the der 48 and prevents sliding movement thereof adjacent blade so that adjacent blades move under the action of the spring 52 so that the in opposite directions of rotation.

blades 12 are retained in their closed position 130

6. Control apparatus according to any one 4 GB 2151 013A 4 of Claims 2 to 4, wherein the gear teeth of the rack which engage the gear pinion associated with one blade are disposed on the same side of the aperture in the operating member to the gear teeth of the rack which engage the gear pinion associated with the adjacent blade so that adjacent blades move in the same directions of rotation.

7. Control apparatus according to any one of the preceding claims, wherein the pivotal axes of the blades are disposed in a single plane and the operating member is slidably mounted in the housing for linear movement in a direction parallel to said single plane.

8. Control apparatus according to any one of the preceding claims, wherein resilient means is provided for urging the blades towards a closed position in which adjacent blades are aligned in touching contact with each other. 20

9. Control apparatus according to Claim 8, wherein the resilient means comprises one or more springs extending between the operating member and the housing.

10. Control apparatus according to any one of Claims 1 to 7, wherein automatic closure means is drivably connected to the operating member via a rack and pinion drive for automatically urging the blades towards their closed position. 30

11. Control apparatus according to Claim 10, wherein the automatic closure means includes a smoke or heat detector which initiates closing movement of the blades when the presence of smoke or excessive heat is de- tected.

12. Control apparatus according to any one of the preceding claims, wherein an operating handle is connected to the operating member to enable the position of the blades to be manually controlled.

13. Control apparatus according to any one of Claims 1 to 11, wherein a power-operated actuator is connected to the operating mem ber to control the position of the blades.

14. Control apparatus according to any one of the preceding claims, wherein adjustable stop means associated with the operating member is provided to enable the position, such as the closed position, of the blades to be adjusted.

Control apparatus according to any one of the preceding claims, wherein switch means associated with and operated by movement of the operating member relatively to the housing is provided for enabling an indication of the position of the blades to be obtained.

16. Control apparatus constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

Printed in the United Kingdom for Her Majesty's Stationery Office. Dd 8818935, 1985. 4235. Published at The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.