IE903652A1 - Manufacturing a Rigid Foam Board - Google Patents

Description

The invention relates to a method for manufacturing a rigid polymeric insulating foam board of the type comprising a first substrate, a second substrate and a foam layer between the substrates. Such boards are typically used in the construction of walls, ceilings, roofs or the like.

According to the invention there is provided a method for manufacturing a rigid polymeric insulating foam board of the type comprising a first substrate, a second substrate and a foam layer between the substrates, the method comprising the steps of :leading a first substrate from a first reel, applying liquid foam reactants onto the first substrate, applying a second substrate from a second reel over the liquid foam reactants and the first substrate, heating the substrates and foam reactants in an oven to allow the foam to expand, and - 3 cutting the foam board thus formed to a desired length, wherein the method includes the step of maintaining the longitudinal tension of at least one of the substrates substantially constant as the substrate is led off the retfl.

In one embodiment of the invention the longitudinal tension of the substrate is maintained substantially constant by sensing the amount of substrate remaining on the reel and applying a braking force to the reel to maintain the longitudinal tension of the substrate substantially constant.

In a preferred embodiment of the invention the braking force is applied by applying fluid under pressure to a diaphragm operated reel brake, the pressure of the fluid applied being varied in response to the amount of substrate remaining on the reel as determined by the sensing means.

Preferably the pressure of the fluid is varied by a control valve means, the amount to which the valve is opened and closed being determined by the sensing means.

In a preferred embodiment of the invention the method includes 20 the step of maintaining the longitudinal tension of both substrates substantially constant as the substrates are led off their respective reels. v - 4 In another aspect the invention provides an apparatus for use in the method of the invention comprising:sensing means for sensing the amount of substrate on a reel of substrate material, braking means for applying a braking pressure to the reel, and operating means for varying the braking pressure applied by the braking means in response to the sensing means.

In a preferred embodiment of the invention the sensing means comprises a sensing arm with a follower element mounted thereon for engagement against the substrate on the reel, the arm being freely pivotally mounted for pivotal movement to operate the operating means.

In a particularly preferred embodiment of the invention the braking means is a fluid operated diaphragm brake and the operating means includes valve means for controlling the pressure of the operating fluid in response to the position of the follower of the sensing arm. % - 5 Preferably the operating means includes a cam operated by the sensing arm for operating the valve.

In one embodiment of the invention the cam is carried by the 5 sensing arm, the cam moving on movement of the sensing arm to progressively close the valve and decrease the braking pressure as the substrate is led off the reel.

Preferably the sensing arm is cranked intermediate the ends thereof and is freely pivotably mounted in a bushing mounted to the bed of a housing in which the reel is rotatably mounted.

In a particularly preferred embodiment of the invention there are two reels and separate sensing means, braking means and operating means provided for each reel. Preferably there is a common fluid supply for the braking means for the reels.

The invention will be more clearly understood from the following description thereof given by way of example only with reference to the accompanying drawings, in which:Fig. 1 is a side view of portion of an apparatus for use 20 in manufacturing a rigid polymeric insulating foam board, Fig. 2 is a perspective view of a portion of the apparatus, % - 6 Fig. 3 is another perspective view of part of the apparatus, and Fig. 4 is a side view on an enlarged scale of the part of the apparatus illustrated in Fig. 3.

Referring to the drawings there is illustrated part of an apparatus indicated generally by the reference numeral 1 for manufacturing a rigid polymeric insulating foam board. The apparatus includes a first stock reel 2 for a first substrate 3 and a second stock reel 4 for a second substrate 5. The first substrate 3 is led from the reel 2 to a bed 7 and liquid foam reactants from a supply (not shown) are laid down onto the substrate 3 through an applicator head 8. The second substrate 5 is led from the stock reel 4 over a series of guide rollers and onto a mangle roller 9. The mangle roller 9 applies the second substrate 5 over the liquid foam reactants and distributes the reactants evenly over the substrate. The sandwich defined by the substrates 3, 5 and the liquid foam reactants is then passed into an oven (only portion 10 of which is illustrated Fig. 1) where the foam reactants are allowed to expand forming a rigid insulating foam board which is cut by saws (not shown) to a desired length and width. - Ί The substrates 3, 5 may be of any suitable desired materials such as of glass fibre material or aluminium foil material with or without an intermediate polyethylene liner.

The method according to the invention includes the step of 5 maintaining the longitudinal tension of at least one and preferably both substrates 3, 5 substantially constant as the substrates are led off the respective stock reels 2, 4. The tension of the substrates as they are being led off the reels varies depending on the amount of substrate which has already been used from a reel or where the substrate is drawn from the reel. This is particularly important for certain types of materials such as stippled aluminium foil material which is liable to tear in use because of the difference in tension resulting in considerable wastage, maintenance and downtime.

In the invention the longitudinal tension of the substrates 3, 5 is maintained suostantially constant by sensing the amount of substrate remaining on the respective reels 2, 4 and applying a variable braking force to the reels 2, 4 to maintain the longitudinal tension of the substrates 3, 5 substantially constant in use. The method and apparatus will be specifically described with reference to the stock reel 2 for the first substrate 3, similar apparatus being also used for the reel 4 for the second substrate 5 and like parts being assigned the same reference numerals. - 8 Referring in particular to Figs. 2 to 4 the reel 2 is fitted with a brake 20 which in this case is operated by a diaphragm, the braking force applied by the brake 20 being varied by varying the pressure of the operating fluid fed to the diaphragm of the brake 20. In this case the operating fluid is compressed air which is fed to the diaphragm of the brake 20 along a supply line 25 which is common for the brakes for both reels 2, 4, the line 25 having connectors 26 to which supply lines 27, 28 are connected which in turn are connected to the in-feed side of control valves 29, 30, out-feed lines 31, 32 of which are connected to the diaphragms of the brakes .

Sensing means for sensing the amount of substrate remaining on the stock reel 2 in this case comprises a sensing arm 40 which is cranked intermediate the ends thereof and is freely pivotally mounted in a bushing 41 fixed to a framework 42 in or on which the reels 2, 4 are rotatably mounted.

The arm 40 has a cylindrical follower element 42 at the free end thereof for engagement against the substrate 3 on the reel 2 as illustrated. A cam 45 is mounted at the other end of the sensing arm 40, the cam surface of the cam 45 engaging a plunger 46 which operates the control valve 29. As the substrate 2 is wound off the reel 4 the connecting arm 40 pivots inwardly in the direction of the arrow A in Fig. 3, the follower element 42 following the thickness of the stock - 9 substrate remaining on the reel. As the sensing arm 40 moves inwardly the cam 45 rotates operating the plunger 46 to control the pressure of operating fluid fed through the line 31 to the diaphragm of the brake 20. In this way the braking pressure applied by the brake 20 is varied to maintain the longitudinal tension of the substrate 3 substantially constant as the substrate 3 is led from the stock reel 2. A position of the sensing arm 40 and cam 45 when a substantial amount of the substrate stock has been led from the reel 2 is illustrated in dotted outline in Fig. 4.

Many variations on the specific embodiments of the invention described will be readily apparent and accordingly the invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims (12)

1. ΓΤ,ΆΓΜ.ς

1. A method for manufacturing a rigid polymeric insulating foam board of the type comprising a first substrate, a second substrate and a foam layer between the substrates, 5 the method comprising the steps of:leading a first substrate from a first reel, applying liquid foam reactants onto the first substrate, applying a second substrate from a second reel over 10 the liquid foam reactants and the first substrate, heating the substrates and foam reactants in an oven to allow the foam to expand, and cutting the foam board thus formed to a desired length, 15 wherein the method includes the step of maintaining the longitudinal tension of at least one of the substrates substantially constant as the substrate is led off the real. - 11

2. A method as claimed in claim 1 wherein the longitudinal tension of the substrate is maintained substantially constant by sensing the amount of substrate remaining on the reel and applying a braking force to the reel to 5 maintain the longitudinal tension of the substrate substantially constant.

3. A method as claimed in claim 2 wherein the braking force is applied by applying fluid under pressure to a diaphragm operated reel brake, the pressure of the fluid 10 applied being varied in response to the amount of substrate remaining on the reel as determined by the sensing means .

4. A method as claimed in claim 3 wherein the pressure of the fluid is varied by a control valve means, the amount 15 to which the valve is opened and closed being determined by the sensing means.

5. A method as claimed in any preceding claim wherein the method includes the step of maintaining the longitudinal tension of both substrates substantially constant as the 20 substrates are led off their respective reels.

6. A method substantially as hereinbefore described with reference to the accompanying drawings. - 12 7. Apparatus for use in the method of any preceding claim comprising:sensing means for sensing the amount of substrate on a reel of substrate material, 5 braking means for applying a braking pressure to the reel, and operating means for varying the braking pressure applied by the braking means in response to the sensing means .

7. 10 8. Apparatus as claimed in claim 7 wherein the sensing means comprises a sensing arm with a follower element mounted thereon for engagement against the substrate on the reel, the arm being freely pivotally mounted for pivotal movement to operate the operating means. 15 9 . Apparatus as claimed in claim 8 wherein the braking means is a fluid operated diaphragm brake and the operating means includes valve means for controlling the pressure of the operating fluid in response to the position of the follower of the sensing arm. - 13 10. Apparatus as claimed in claim 9 wherein the operating means includes a cam operated by the sensing arm for operating the valve.

8. 11. Apparatus as claimed in claim 10 wherein the cam is 5 carried by the sensing arm, the cam moving on movement of the sensing arm to progressively close the valve and decrease the braking pressure as the substrate is led off the reel.

9. 12. Apparatus as claimed in any of claims 8 to 11 wherein the 10 sensing arm is cranked intermediate the ends thereof and is freely pivotably mounted in a bushing mounted to the bed of a housing in which the reel is rotatably mounted.

10. 13. Apparatus as claimed in any of claims 8 to 12 wherein there are two reels and separate sensing means, braking 15 means and operating means provided for each reel.

11. 14. Apparatus as claimed in claim 13 wherein there is a common fluid supply for the braking means for the reels.

12. 15. Apparatus substantially as hereinbefore described with reference to the accompanying drawings. - 14 16. Rigid foam board whenever produced by a method as claimed in any of claims 1 to 7 or using an apparatus as claimed in any of claims 8 to 15.