CA1231289A - Design for fire limiters or other safety appliances in ventilation installations - Google Patents
Design for fire limiters or other safety appliances in ventilation installationsInfo
- Publication number
- CA1231289A CA1231289A CA000459798A CA459798A CA1231289A CA 1231289 A CA1231289 A CA 1231289A CA 000459798 A CA000459798 A CA 000459798A CA 459798 A CA459798 A CA 459798A CA 1231289 A CA1231289 A CA 1231289A
- Authority
- CA
- Canada
- Prior art keywords
- fuse
- sleeve
- fuse device
- fire
- parts
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
ABSTRACT OF THE DISCLOSURE
A fuse device for tripping fire limiters or other safety appliances in ventilation installations, comprising a fuse body, an element of fusible material, arranged to keep parts of the fuse device in a fixed position relative to each other, when in the solid state and permit the parts of the fuse to move relative to each other, when in the molten state, and a narrow flow passage in the fuse device through which the fusible material flows when in the liquid state, under the action of the internal pressure in the fuse material caused by clamping forces acting on the fuse, for the purpose of tripping the fire limiter or other safety appliance.
A fuse device for tripping fire limiters or other safety appliances in ventilation installations, comprising a fuse body, an element of fusible material, arranged to keep parts of the fuse device in a fixed position relative to each other, when in the solid state and permit the parts of the fuse to move relative to each other, when in the molten state, and a narrow flow passage in the fuse device through which the fusible material flows when in the liquid state, under the action of the internal pressure in the fuse material caused by clamping forces acting on the fuse, for the purpose of tripping the fire limiter or other safety appliance.
Description
The present invention relates to a fuse deice for tripp-ing fire limiters or other safety applicances in Yentilation in-stallations, comprising a fuse body and a fuse element, the fuse element being disposed, when in the solid state, to maintain the parts of the fuse device in a certain position relative to each other and to permit the parts of the fuse to move relative to each other when in liquid state.
It would be highly welcome in fire limiters if one fuse could be used more often than just once. Subsequent to false or test tripping for reasons other than fire, which occurs fre-quently, the same fuse device could be immediately reset. The operability of a fire limiter could be checked in a simple and convenient manner by tripping and resetting the closing member, e.g. the flap or louvre pack. Convenient detachability and re-placeability of the fuse are also advantages.
The currently most well known and most used design is a strip fuse. In this structure two metal strips are soldered together with the aid of fuse material having the desired melting point. When the temperature of the fuse material rises above a pre-determined limit value, that is to the melting temperature, the strips become detached from each other. A drawback of a structure of this kind is however that the same fuse cannot be reused after false or test tripping. A strip fuse is quite likely to suffer damage or to break and there is also the problem of the long-term strength of the fuse material and the difficulty in controlling the soldering process.
Another fuse design known in the art is the so-called glass ball fuse, in which between two latches is placed a glass ball filled with a liquid with a high coefficient thermal expan-sion. The ball breaks when the liquid expands. The set-up of the latches relative to each other is such that when the glass ball bursts as the temperature reaches its given limit value they get 3 ~-D
free from each other. A drawback of this deslgn is its single-use, expensive, and inconvenient construction.
At present, reuse of the fuses proper is not possible, although triggers based on thermal expansion are known in the art.
For instance, a tripping mechanism is known which comprises a stack assembled of bimetal strips that expands as it is heated and detaches a pin from a locking hole to trip the device. A drawback of the structure has been found to be that the bimetal strips react slowly to temperature increase, and moreover the design is expen-sive; it is rather susceptible to interference, easily damaged, sensitive to corrosion, and in the case of a fault, awkward to re-pair.
An object of the present invention is to provide an improvement in fuse designs known in the art. A more detailed object of the invention is to provide a fuse design based on the melting of a substance and which is durable, reliable in operation, resistant to corrosion, easy to test, favourable as to its manu-facturing cost, easy to detach or replace, and which permits re-peated use of the fuse.
In the German patent publication No. 2,261,153 is dis-closed a fuse device in which the fuse plate is subject to pres-sure. After the fuse material has melted, the molten substance flows off in an uncontrolled manner, and therefore reuse is not possible. In addition, the design requires an ample amount of fuse material. The softening of the fuse material at temperature below the melting point may also cause failure of the locking in this type of fuse because in it a harmful creep is possible, which is a phenomenon typical of fuse materials.
According to the present invention there is provided a fuse device for tripping fire limiters or other safety appliances in ventilation installations, comprising a fuse body, an element of fusible material, arranged to keep parts of the use device in a fixed position relative to each other, when'in the solid state and permit the parts of the fuse to move relative to each other, when in the molten state, and a narrow flow passage in the fuse device through which the fusible material flows when in the liquid stater under the action of the internal pressure in the fuse material caused by clamping forces acting on the fuse, for the purpose of tripping the fire limiter or other safety appliance.
In a preferred embodiment, after the internal pressure generated in the fuse matexial by the locking force has dropped below the flowing limit, the flow of the fuse material ceases and the parts of the fuse cease to move relative to each other. As the temperature falls below the solidifying limit the fuse material solidifies so that the parts of the fuse remain in their new posi-tion, thus enabling the fire limiter or other safety applicance to be reset with the aid of the same fuse one or more times.
With the fuse design of the invention, numerous signi-ficant advantages are gained, such as good durability, reliability in operation, resistance to corrosion, favourable production costs, convenient testing, convenient detachability, and replaceability.
In the choice of material no attention need be paid to solder-ability either. In addition, no undue problems are caused by the tripping of these fire limiters due to faults or for testing, since they are so easy to reset.
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:-Fig. 1 shows a first embodiment of the fuse device, Fig. 2 shows a second embodiment of the fuse device;
Fig. 3 shows a third embodiment of the fuse device;
Fig. 4 shows a fourth embodiment of the fuse device;
Fig. 5 shows a fifth embodiment of the fuse device of the invention in a schematic cross-section; and Fig. 6 shows a fuse device as in Fig. 2, installed on a fire damper, in a schematic cross-section.
The fuse device shown in Fig. 1 has been generally indica-ted by the reference numeral 10. The fuse 10 comprises a body part 11, in the present embodiment provided with a thinner tip portion lla. On the end of the tip portion lla of the body part 11 is disposed a sleeve-like member 12, and between the tip part lla and the sleeve-like member 12 is placed the fuse material 13 which keeps the sleeve-like member 12 at a certain preselected axial distance with reference to the body part 11 when the body part 11 and the sleeve-like member 12 tend under influence of external force to move further into each other. In this embodi-ment, the sleeve like member 12 is open at both ends. It is thus understood that the sleeve-like member 12 is joined by the fuse material 13 to the tip portion lla of the body part 11. When the temperature rises, the fuse material 13 becomes liquid, and under the effect of the axial force the sleeve-like member 12 moves in the direction of the body part 11.
The fuse device shown in the embodiment or Fig. 2 is generally indicated by the reference numberal 20. In this embodi-ment, a sleeve-like member 22 provided with a bottom 24 is disposed around the tip portion 21a of the body part 21, and between the tip portion 21a and the sleeve-like member 22 is placed the fuse material 23, of which the viscosity in the course of temperature increase changes drastically at the melting point and owing to the axial force fuse material 23 is enabled to flow into the free space between the tip portion 21a and the sleeve-like member 22, whereby the sleeve-like member 22 is enabled to move in the direc-tion of the body part 21. It is to be particularly noted that at normal temperatures the fluidity of the fuse material is virtually nil, because of which no flow of the fuse material will take place even at extreme pressures, provided that clearance between the tip portion 21a and the sleeve-like member 22 is appropriate in magnitude.
~;3~
The fuse device shown in Fig. 3 is generally indicated by the reference numeral 30. In this embodiment, too, a sleeve-like member 32 having a bottom 34 is disposed about the tip portion 31a of the body part 31.
The fuse material 33 is disposed between the tip portion 31a and the sleeve-like member 32. In this embodiment, the sleeve-like member 32 is provided with a hole or passage 35, through which the controlled flow of the fuse material will take place.
Also in the embodiment of Fig. 4, there has been placed a sleeve-like member 42 with bottom 43 around the tip portion 41a of the body part 41 of the fuse device, generally indicated by the reference numeral 40/ and the fuse material 43 is disposed between the tip portion 41a and the sleeve-like member 42. The principle of operation of the permanent fuse 40 is the same as that of the permanent fuse 30 shown in Fig. 3, with the difference that in the embodiment of Fig. 4 the passage or hole 45 has been made in the tip portion 41a of the body part 41. Consequently, in this embodi-ment the liquid fuse material flows into a passage or hole 45 in the tip portion 4la.
The fuse device shown in Fig. 5 is generally indicated by the reference numeral 50. In this embodiment, too, a sleeve-like member 52 provided with bottom 54 is disposed on the tip por-tion 51a of the body part 51. A button of fuse material is placed between the tip portion 51a and the sleeve-like member 52. In this embodiment, the fuse material 53 is an annular fuse material button provided with an aperture 55, that is, the fuse material button 53 itself has a hole or passage 55, into which the liquid fuse material can flow.
The operation of the fuse device 10,20,30,40 or 50 of the invention is as follows: When the fuse device 10 is connected to a fire limiter, a compressive force acts on the fuse material 13,23,33,43,53 over the body part 11,21,31,41,51 and the sleeve-like Z~
member 12,22,32,42,52, whereby the movement of' the sleeve-like member and of the body part 11,21,31~41,51 of the fuse with reference to each other is prevented while the fuse material is in solid state. When the temperature rises to the melting temperature of the fuse material 13,23,33,43,53, the fluidity of the fuse material begins to become considerably mobile and the sleeve-like member will under influence of the force acting on the sleeve-like member be displaced with reference to the body part, whereby the fire limi-ter is tripped.
In Fig. 6 is presented an advantageous practical applica-tion of the fuse device of the invention. In this embodiment, the fuse 20 of Fig. 2 is installed on a fire damper, the shell of which is indicated by the reference numeral 26. To the shell 26 is attached a shaped counterpiece 27, and a clamping arc 28 attached to the closing plate of the fire damper (not depicted) is clamped by the aid of the fuse and the counterpiece 27 so that in the clamping arc 28 is impacted between the bottom 24 of the sleeve-like member 22 of the fuse and the counterpiece 27. The clamping may also be accomplished without counterpiece 27, in which case the sleeve-like part 22 directly clamps the clamping arc 28. The other end of the body part 21, threaded over a certain length, of the fuse 20 is shaped as a screw head 29, whereby it is simple to accomplish positive clamping of the clamping arc 28 by turning the body part 21. The body part 21 is encircled by a body part 21b provided with threads and attached to the shell 26.
When the temperature is low enough, the closing member can be set with the aid of the fuse. The action of the fuse is based on changing viscosity of the fuse material and/or its ability to reattach when the temperature has gone down. The body parts 21 and 21b are so dimensioned that setting of the fire limiter cannot be accomplished without fuse material.
The fuse can be used until the fuse material has run 3~
short in the space between the body paxt and the sleeve-like member, or until the empty space 55 shown in Fig. 5 has been filled.
Thereafter, a new fuse material button can be inserted in the fuse or the entire fuse may be replaced. By means of the fuse material quantity, the number of times one fuse can be used may be regulated.
~0
It would be highly welcome in fire limiters if one fuse could be used more often than just once. Subsequent to false or test tripping for reasons other than fire, which occurs fre-quently, the same fuse device could be immediately reset. The operability of a fire limiter could be checked in a simple and convenient manner by tripping and resetting the closing member, e.g. the flap or louvre pack. Convenient detachability and re-placeability of the fuse are also advantages.
The currently most well known and most used design is a strip fuse. In this structure two metal strips are soldered together with the aid of fuse material having the desired melting point. When the temperature of the fuse material rises above a pre-determined limit value, that is to the melting temperature, the strips become detached from each other. A drawback of a structure of this kind is however that the same fuse cannot be reused after false or test tripping. A strip fuse is quite likely to suffer damage or to break and there is also the problem of the long-term strength of the fuse material and the difficulty in controlling the soldering process.
Another fuse design known in the art is the so-called glass ball fuse, in which between two latches is placed a glass ball filled with a liquid with a high coefficient thermal expan-sion. The ball breaks when the liquid expands. The set-up of the latches relative to each other is such that when the glass ball bursts as the temperature reaches its given limit value they get 3 ~-D
free from each other. A drawback of this deslgn is its single-use, expensive, and inconvenient construction.
At present, reuse of the fuses proper is not possible, although triggers based on thermal expansion are known in the art.
For instance, a tripping mechanism is known which comprises a stack assembled of bimetal strips that expands as it is heated and detaches a pin from a locking hole to trip the device. A drawback of the structure has been found to be that the bimetal strips react slowly to temperature increase, and moreover the design is expen-sive; it is rather susceptible to interference, easily damaged, sensitive to corrosion, and in the case of a fault, awkward to re-pair.
An object of the present invention is to provide an improvement in fuse designs known in the art. A more detailed object of the invention is to provide a fuse design based on the melting of a substance and which is durable, reliable in operation, resistant to corrosion, easy to test, favourable as to its manu-facturing cost, easy to detach or replace, and which permits re-peated use of the fuse.
In the German patent publication No. 2,261,153 is dis-closed a fuse device in which the fuse plate is subject to pres-sure. After the fuse material has melted, the molten substance flows off in an uncontrolled manner, and therefore reuse is not possible. In addition, the design requires an ample amount of fuse material. The softening of the fuse material at temperature below the melting point may also cause failure of the locking in this type of fuse because in it a harmful creep is possible, which is a phenomenon typical of fuse materials.
According to the present invention there is provided a fuse device for tripping fire limiters or other safety appliances in ventilation installations, comprising a fuse body, an element of fusible material, arranged to keep parts of the use device in a fixed position relative to each other, when'in the solid state and permit the parts of the fuse to move relative to each other, when in the molten state, and a narrow flow passage in the fuse device through which the fusible material flows when in the liquid stater under the action of the internal pressure in the fuse material caused by clamping forces acting on the fuse, for the purpose of tripping the fire limiter or other safety appliance.
In a preferred embodiment, after the internal pressure generated in the fuse matexial by the locking force has dropped below the flowing limit, the flow of the fuse material ceases and the parts of the fuse cease to move relative to each other. As the temperature falls below the solidifying limit the fuse material solidifies so that the parts of the fuse remain in their new posi-tion, thus enabling the fire limiter or other safety applicance to be reset with the aid of the same fuse one or more times.
With the fuse design of the invention, numerous signi-ficant advantages are gained, such as good durability, reliability in operation, resistance to corrosion, favourable production costs, convenient testing, convenient detachability, and replaceability.
In the choice of material no attention need be paid to solder-ability either. In addition, no undue problems are caused by the tripping of these fire limiters due to faults or for testing, since they are so easy to reset.
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:-Fig. 1 shows a first embodiment of the fuse device, Fig. 2 shows a second embodiment of the fuse device;
Fig. 3 shows a third embodiment of the fuse device;
Fig. 4 shows a fourth embodiment of the fuse device;
Fig. 5 shows a fifth embodiment of the fuse device of the invention in a schematic cross-section; and Fig. 6 shows a fuse device as in Fig. 2, installed on a fire damper, in a schematic cross-section.
The fuse device shown in Fig. 1 has been generally indica-ted by the reference numeral 10. The fuse 10 comprises a body part 11, in the present embodiment provided with a thinner tip portion lla. On the end of the tip portion lla of the body part 11 is disposed a sleeve-like member 12, and between the tip part lla and the sleeve-like member 12 is placed the fuse material 13 which keeps the sleeve-like member 12 at a certain preselected axial distance with reference to the body part 11 when the body part 11 and the sleeve-like member 12 tend under influence of external force to move further into each other. In this embodi-ment, the sleeve like member 12 is open at both ends. It is thus understood that the sleeve-like member 12 is joined by the fuse material 13 to the tip portion lla of the body part 11. When the temperature rises, the fuse material 13 becomes liquid, and under the effect of the axial force the sleeve-like member 12 moves in the direction of the body part 11.
The fuse device shown in the embodiment or Fig. 2 is generally indicated by the reference numberal 20. In this embodi-ment, a sleeve-like member 22 provided with a bottom 24 is disposed around the tip portion 21a of the body part 21, and between the tip portion 21a and the sleeve-like member 22 is placed the fuse material 23, of which the viscosity in the course of temperature increase changes drastically at the melting point and owing to the axial force fuse material 23 is enabled to flow into the free space between the tip portion 21a and the sleeve-like member 22, whereby the sleeve-like member 22 is enabled to move in the direc-tion of the body part 21. It is to be particularly noted that at normal temperatures the fluidity of the fuse material is virtually nil, because of which no flow of the fuse material will take place even at extreme pressures, provided that clearance between the tip portion 21a and the sleeve-like member 22 is appropriate in magnitude.
~;3~
The fuse device shown in Fig. 3 is generally indicated by the reference numeral 30. In this embodiment, too, a sleeve-like member 32 having a bottom 34 is disposed about the tip portion 31a of the body part 31.
The fuse material 33 is disposed between the tip portion 31a and the sleeve-like member 32. In this embodiment, the sleeve-like member 32 is provided with a hole or passage 35, through which the controlled flow of the fuse material will take place.
Also in the embodiment of Fig. 4, there has been placed a sleeve-like member 42 with bottom 43 around the tip portion 41a of the body part 41 of the fuse device, generally indicated by the reference numeral 40/ and the fuse material 43 is disposed between the tip portion 41a and the sleeve-like member 42. The principle of operation of the permanent fuse 40 is the same as that of the permanent fuse 30 shown in Fig. 3, with the difference that in the embodiment of Fig. 4 the passage or hole 45 has been made in the tip portion 41a of the body part 41. Consequently, in this embodi-ment the liquid fuse material flows into a passage or hole 45 in the tip portion 4la.
The fuse device shown in Fig. 5 is generally indicated by the reference numeral 50. In this embodiment, too, a sleeve-like member 52 provided with bottom 54 is disposed on the tip por-tion 51a of the body part 51. A button of fuse material is placed between the tip portion 51a and the sleeve-like member 52. In this embodiment, the fuse material 53 is an annular fuse material button provided with an aperture 55, that is, the fuse material button 53 itself has a hole or passage 55, into which the liquid fuse material can flow.
The operation of the fuse device 10,20,30,40 or 50 of the invention is as follows: When the fuse device 10 is connected to a fire limiter, a compressive force acts on the fuse material 13,23,33,43,53 over the body part 11,21,31,41,51 and the sleeve-like Z~
member 12,22,32,42,52, whereby the movement of' the sleeve-like member and of the body part 11,21,31~41,51 of the fuse with reference to each other is prevented while the fuse material is in solid state. When the temperature rises to the melting temperature of the fuse material 13,23,33,43,53, the fluidity of the fuse material begins to become considerably mobile and the sleeve-like member will under influence of the force acting on the sleeve-like member be displaced with reference to the body part, whereby the fire limi-ter is tripped.
In Fig. 6 is presented an advantageous practical applica-tion of the fuse device of the invention. In this embodiment, the fuse 20 of Fig. 2 is installed on a fire damper, the shell of which is indicated by the reference numeral 26. To the shell 26 is attached a shaped counterpiece 27, and a clamping arc 28 attached to the closing plate of the fire damper (not depicted) is clamped by the aid of the fuse and the counterpiece 27 so that in the clamping arc 28 is impacted between the bottom 24 of the sleeve-like member 22 of the fuse and the counterpiece 27. The clamping may also be accomplished without counterpiece 27, in which case the sleeve-like part 22 directly clamps the clamping arc 28. The other end of the body part 21, threaded over a certain length, of the fuse 20 is shaped as a screw head 29, whereby it is simple to accomplish positive clamping of the clamping arc 28 by turning the body part 21. The body part 21 is encircled by a body part 21b provided with threads and attached to the shell 26.
When the temperature is low enough, the closing member can be set with the aid of the fuse. The action of the fuse is based on changing viscosity of the fuse material and/or its ability to reattach when the temperature has gone down. The body parts 21 and 21b are so dimensioned that setting of the fire limiter cannot be accomplished without fuse material.
The fuse can be used until the fuse material has run 3~
short in the space between the body paxt and the sleeve-like member, or until the empty space 55 shown in Fig. 5 has been filled.
Thereafter, a new fuse material button can be inserted in the fuse or the entire fuse may be replaced. By means of the fuse material quantity, the number of times one fuse can be used may be regulated.
~0
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A fuse device for tripping fire limiters or other safety appliances in ventilation installations, comprising a fuse body, an element of fusible material, arranged to keep parts of the fuse device in a fixed position relative to each other, when in the solid state and permit the parts of the fuse to move relative to each other, when in the molten state, and a narrow flow passage in the fuse device through which the fusible material flows when in the liquid state, under the action of the internal pressure in the fuse material caused by clamping forces acting on the fuse, for the purpose of tripping the fire limiter or other safety appliance.
2. A fuse device as claimed in claim 1, arranged such that after internal pressure caused by the clamping forces on the fusible material has fallen below the limit at which flow occurs, the fusible material ceases to flow and the parts of the fuse device remain in a fixed position relative to each other, and that dec-rease of temperature below the limit at which solidification occurs causes the fusible material to solidify so that the parts of the fuse device remain in this position, thus enabling the fire limiter or other safety appliance to be reset with the aid of the same fuse device one or more times.
3. A fuse device as claimed in claim 1, wherein the fusible element is provided with a sleeve-like member encircling the fuse body and the fuse material is located between the fuse body and the sleeve-like member, the fusible material being dis-posed so as to maintain the sleeve-like member in a fixed position relative to the fuse body.
4. A fuse device as claimed in claim 3, wherein the sleeve-like member is disposed around a tip portion of the fuse body.
5. A fuse device as claimed in claim 3 or 4, wherein the sleeve-like member is open at both ends.
6. A fuse device as claimed in claim 3 or 4, wherein the sleeve-like member is provided with a bottom and the narrow flow passage is formed in the sleeve-like member or in the fuse body.
7. A fuse device as claimed in claim 3 or 4, wherein the fusible element comprises button fuse material provided with a passage through which the fuse material can flow in the liquid state.
8. A fuse device as claimed in claim 1, 2 or 3, wherein the fuse body is provided with threads so that it can be screwed into or attached to the shell threaded part of the fire damper.
9. A fuse device as claimed in claim 3, wherein the fuse element is arranged to clamp a clamping arc affixed to the closing plate of a fire damper, either between a counterpiece attached to the shell of the fire damper and the sleeve-like member, or dir-ectly without counterpiece.
10. A fuse device as claimed in claim 1, 2 or 3, wherein the fuse body comprises at least two parts so disposed relative to each other that the fuse device cannot be used for resetting the fire limiter or other safety appliance after the fuse material has been depleted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000459798A CA1231289A (en) | 1984-07-26 | 1984-07-26 | Design for fire limiters or other safety appliances in ventilation installations |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000459798A CA1231289A (en) | 1984-07-26 | 1984-07-26 | Design for fire limiters or other safety appliances in ventilation installations |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1231289A true CA1231289A (en) | 1988-01-12 |
Family
ID=4128400
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000459798A Expired CA1231289A (en) | 1984-07-26 | 1984-07-26 | Design for fire limiters or other safety appliances in ventilation installations |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1231289A (en) |
-
1984
- 1984-07-26 CA CA000459798A patent/CA1231289A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |