GB2178077A

GB2178077A - Fabric stenter frame

Info

Publication number: GB2178077A
Application number: GB08609117A
Authority: GB
Inventors: Helge Freiberg
Original assignee: A Monforts GmbH and Co
Current assignee: A Monforts GmbH and Co
Priority date: 1985-07-25
Filing date: 1986-04-15
Publication date: 1987-02-04
Also published as: IT1191753B; FR2585380A1; IT8620251A0; DE3526584A1; GB8609117D0; JPS6335874A; IT8620251A1

Abstract

To ensure that the chain 6 of a fabric stenter frame does not attain high temperatures which are inadmissible for the chain bearings, means 14 of blowing ambient air on the bearings of the chain are associated with the intake field 1 and/or outlet field 3 of the chain track 7. The longitudinal edges of the fabric 5 are clamped by clamping means 19 of the endless chain 6 and the fabric travels via the intake field 1 to a heat treatment field 2 before travelling through the outlet field 3. The blowing means 14 comprises a fan 26 which blows air through ducts 24, 25 and apertures 27 formed underneath each chain track 7. The chain 6 may be a roller or a slide chain. <IMAGE>

Description

SPECIFICATION Fabric stenter frame The invention relates to a fabric stenter frame for heat treating a web of textile fabric passed through an intake field, a heat treatment field and an outlet field while spread out by an endless roller chain via clamping means engaging the longitudinal edges of the fabric web, each roller chain having on its chain links bearings to accommodate the forces emanating from the clamping means, the roller chain guide means provided being a chain track passing through all three fields at the edges of the web of fabric.

Roller chains used in fabric stenter frames have not only the chain bearings which connect the individual chain links and which accommodate longitudinal forces acting in the longitudinal direction of the chain but on each clamping means roller bearings which accommodate transverse forces emanating from the web of fabric and extending transversely of the longitudinal direction of the chain. Furthermore, the chain may have wheels with support bearings to accommodate the weight of the chain. In moder fabric stenter frames, the bearings are designed to operate without maintenance for several thousand hours by the use of non-cracking greases which are stable at conventional treatment temperatures of up to about 230"C.

If the heat treatment field of the machine is operated at a temperature of about 220"C, then in continuous operation the chain becomes heated to about 210 C. With rising working temperature, the effective life of the bearing grease diminshed markedly. It has however also been found that during operation of the heat treatment field at substantially lower temperatures than 220"C, the effective life of the bearing grease is markedly prolonged, for example the effective life at working temperatures of 180 is prolonged to about 1.3 to 1.8 times and at 150"C to about 2.2 to 3.0 times the effective life at a working temperature of 220"C.

Since renewing bearing grease in the numerous bearings of the roller chains of a fabric stenter frame is time-consuming, the desire is to make as long as possible the period between maintenance operations. The temperature adjusted in the heat treatment field depends either rigidly upon the treatment task and can therefore not be changed or it is chosen to be as high as possible in order to accelerate operation. To prolong the effective life, therefore, bearing greases are used which remain stable and effective at the highest possible temperatures while being stable for an economically viable minimum period. Attempts have also been made to use completely maintenance-free plain bearings but the working surfaces of such bearings are likewise resistant only up to specific maximum temperatures.

The invention is based on the problem of prolonging the effective life of the bearings on the roller chain or sliding chain of a fabric stenter frame without substantially altering the chain or its track. The solution according to the invention, for a machine mentioned at the outset, resides in associating with each chain track in the intake field and/ or outlet field, separate means for blowing ambient air onto the chain.

Preferably, the blowing means are provided both in the forward run and also in the return run of each roller chain track. By blowing on the chains and particularly on the bearings thereof and over a specific length in the intake field and/or in the outlet field of the machine, the rise in temperature undergone by the chain at each pass through the heat treatment field, can, in any case above a specific temperature, be cooled again so that in continuous operation the chain does not exceed a predetermined maximum temperature. It goes without saying that this maximum temperature depends upon the working temperature adjusted in the heat treatment field.

If the working temperature amounts, for example, to 220"C, then by the air cooling according to the invention, a chain temperature of, for example, only 150"C can easily be maintained, which means therefore that the effective life of the chain lubrication can be more than doubled when compared with working without cooling. On the other hand, it is also possible in the heat treatment field to adjust temperatures which are far above the temperature admissible for the bearing grease if cooling means according to the invention are associated with the relevant intake field and/or outlet field.If a frame of the type mentioned at the outset is to be operated in the heat treatment field at a temperature of 300"C, for example, then in the past complicated chain lubrications of only a few hours' effective life were necessary. In contrast, when using the installation according to the invention, just by blowing on the chain outside of the heat treatment field, it is possible to achieve sufficient cooling for an approximately constant chain temperature, a cooling which at the higher temperature offers correspondingly high effeciency and which is sufficiently great that conventional (high-grade) lubricating greases can be used and hitherto conventional effective lives can be obtained.

In a preferred embodiment of the invention, the chain track has beneath and possibly also above the path of the roller chain bearings apertures through which it is possible to blow on the roller chains in a substantially vertical direction. Preferably there is under each chain track an air duct which is to be subject to the action of a fan. Such an air duct should over its length compise a plurality of substantially vertically upwardsly extending apertures through the surface of the bottom, particularly the working surface, of the chain track. If necessary, apertures should also be provided in the covering of the chain track above the roller chain, through which the air to be passed by the fan can be blown.Logically, what has been stated hereinabove for roller chains and roller chain bearings is also applicable to any case where, instead of the roller chain, a plain chain is provided and instead of the roller chain bearings, plain elements are provided on which air is to be blown.

An example of embodiment of the invention will be explained hereinafter in detail with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a plan view of a fabric stenter frame; Figure 2 is a side view of a blowing device according to the invention, partly in section; Figure 3 shows a section taken on the line Ill-Ill inlFigure 2 and Figure 4 is a plan view of the area of the chain track according to Figure 2 equipped with a blowing means.

The fabric stenter frame shown diagrammatically in plan view in Figure 1 comprises an intake field 1, a heat treatment field 2 and an outlet field 3. The zone of the outlet field 3 which is adjacent the heat treatment field 2 can be constructed as a cooling zone 4. Generally, the heat treatment field 2 is constructed as a closed chamber with intake and outlet slots through which to pass the web of fabric 5 and the roller chains 6 which comprise clamping means for gripping the longitudinal edges of the webs of fabric. The two endless roller chains 6 are guided in chain tracks 7 and run over the reversal points at the intake to the intake field 1 and at the outlet of the outlet field 3 over chain sprockets 8.A web of fabric 5 running into the frame is taken up at the intake zone of the intake field on a threading-on or clipping on location 9 at the longitudinal edges and is gripped in needles or clips 10 provided on the outside of each roller chain 6. Accordingly, there is at the outlet of the outlet field 3 a needling-off or unclipping location 11 from which the web of fabric can continue to move, now that it has been released at its edges. It is wound, for example, onto a roller 12. The chain tracks 7 in the region of the intake field 1 can be mounted to pivot relative to one another about vertical axes 13 which if necessary ensures that a web of fabric 5 gripped along its longitudinal edges in the clamping means of the roller chain 6 can be stretched or tensioned in width and can be heat treated or fixed whilst in this condition.

In the intake field 1 and/or in the outlet field 3, blowing means 14 according to the invention can be associated with the chain tracks 7. Such a blowing means 14 is explained in greater detail with reference to Figures 2 to 4. Figure 2 shows a side view (partly in section) through the outlet field 3.

Adjacent to and following on from the wall 15 of the heat treatment zone 2 is a cooling zone 4, after which the fabric 5 continues to move in the direction of the arrow through an open part of the outlet field 3 past a (not shown in Figure 2) needlingoff point 9 and chain sprockets 8. Shown diagram matically in Figure 4 is a plan view of that part of the chain track 7 which is shown from the side in Figure 2. The chain track 7 comprises two plain or moving surfaces 17, namely a working surface 16 for the forward run and a working surface 17 for the return run of the roller chain 6.

Figure 3 shows a section taken on the lines Ill-Ill in Figures 2 and 4. According to Figure 3, the chain track 7 consists of the two working surfaces 16 and 17 in which the roller chain 6 is guided. Inter alia, each roller chain link comprises a roller 18 for accommodating transverse forces 20 exerted by each web of fabric suspended in the frame. The clamping means 19 are in the forward run 21 of the roller chain 6 open and accessible but for reasons of safety they are in the reverse run 22 protected by a cover 23 which expediently extends over the total width of the chain track 7.

In order to cool the roller chain 6 which, during rotation, has been heated up by the heat treatment field 2, there are in the inlet and/or outlet field 1, 3 blowing means 14 associated with the forward and/or reverse runs 21, 22 of the chain track 7. In the example of embodiment shown in Figures 2 to 4, a blowing means 14 consists of in each case one duct 24 and 25 beneath the working surfaces 16 and 17 of forward and reverse runs 21, 22 of the chain track 7. The ducts 24 and 25 are subject to compressed air from a fan 26 which passes ambient air. The compressed air is directed through apertures, particularly tubes 27 in the bottom of the working surfaces 16, 17 in the direction of the bearings, particularly the bearings of the wheel 18 of the roller chain 6. In order to achieve a clearly defined flow of compressed air within the space between the cover 23 and the chain track 7, apertures 28 are provided in the cover 23 and may be equipped with air guide surfaces 29.

Claims

1. Fabric stenter frame for heat treating a web of textile fabric (5) passed through an intake field (1), a heat treatment field (2) and an outlet field (3) while spread out by an endless roller chain (6) via clamping means (19) engaging the longitudinal edges of the fabric web, each roller chain (6) having on its chain links bearings to accommodate the forces (20) emanating from the clamping means (19), the roller chain guide means provided being a chain track (7) passing through all three fields at the edges of the web of fabric, characterized in that in the intake field (1) and/or outlet field (3), separate means are provided for blowing ambient air onto the chain (6).

2. Fabric stenter frame according to Claim 1, characterized in that the blowing means (14) are provided in the forwards and return run (21, 22) of each roller chain (6).

3. Fabric stenter frame according to Claim 1 or 2, characterized in that the chain track (7) has below and possibly above the path of the roller chain bearings apertures (27) for blowing through the roller chain (6) in an approximately vertical direction.

4. Fabric stenter frame according to one or more of Claims 1 to 3, characterized in that underneath each chain track (7) there is an air duct (24, 25) which is to be subjected to the action of a fan (26) and in that the air duct (24, 25) has over its length a plurality of substantially upwardly extending apertures (27) passing through the bottom surface (16, 17), particularly working surface, of each chain track.

5. Fabric stenter frame according to Claim 4, characterized in that a cover (23) over the top face of each chain track (7) has air outlet orifices (28) in the region above the air duct (24, 25).

6. Fabric stenter frame according to Claim 1 to 5, modified in that instead of the roller chain (6) a sliding chain is provided and in that instead of the roller chain bearings, sliding elements are provided on which air is to be blown.

7. Fabric stenter frame as claimed in claim 1, substantially as described herein with reference to and as illustrated in the accompanying drawings.