The present application claims priority from German Patent Application No. 10 2005 052 142.8, dated Oct. 28, 2005, the entire disclosure of which is incorporated herein by reference.
The invention relates to an apparatus at a carding machine having a cylinder, carding elements and displaceable holding elements, which determine the carding spacing between the cylinder clothing and the clothings of the carding elements.
The effective spacing of the tips of a clothing from a machine element lying opposite to the clothing is called the carding gap. The last-mentioned element may also have a clothing but could, instead of that, be formed by a segment of a circuit having a conductive face. The carding gap determines the carding quality. The size (width) of the carding gap is an important machine parameter that shapes both the technology (fibre processing) and the running behaviour of the machine. The carding gap is set as narrow as possible (it is measured in tenths of a millimetre) without the risk of a “collision” of the working elements being incurred. In order to ensure uniform processing of the fibres, the gap needs to be as identical as possible over the whole of the working width of the machine.
The carding gap is affected especially by the machine settings on the one hand and by the condition of the clothing on the other hand. The most important carding gap of the revolving card top carding machine is located in the main carding zone, that is to say between the cylinder and the revolving card top assembly. At least one clothing, which limits the working spacing, is in motion, usually both. In order to increase the production rate of the carding machine, it is sought to select an operating rotational speed, or an operating speed of the moving parts, that is as high as the fibre processing technology allows. The working spacing changes in dependence on the operating conditions. The change occurs in the radial direction (starting from the rotational axis) of the cylinder. The carding gap changes during operation especially as a result of thermal expansion and centrifugal force expansion of the cylinder.
During carding, increasingly large amounts of fibre material are processed per unit of time, which requires higher working component speeds and higher installed outputs. The increasing throughput of fibre material (production rate), even when the working surface area remains constant, results in increased generation of heat as a result of the mechanical work. At the same time, however, the technological carding result (sliver uniformity, degree of cleaning, nep reduction etc.) is constantly being improved, which requires a greater number of effective surfaces in carding engagement and narrower settings of those effective surfaces with respect to the cylinder (tambour). The proportion of synthetic fibres being processed, which—compared with cotton—generate more heat as a result of friction when in contact with the effective surfaces of the machine, is continually increasing. The working components of high-performance carding machines are nowadays totally enclosed on all sides in order to conform to the high safety standards, to prevent the emission of particles into the spinning room environment and to minimise the need for servicing of the machines. Grids or even open, material-guiding surfaces allowing exchange of air are a thing of the past. The said circumstances markedly increase the input of heat into the machine, while the discharge of heat by means of convection is markedly reduced. The resulting more intense heating of high-performance carding machines leads to greater thermoelastic deformation which, on account of the non-uniform distribution of the temperature field, affects the set spacings of the effective surfaces: the gaps between cylinder and card top, doffer, fixed card tops and take-off stations with blades are reduced. In an extreme case, the set gap between the effective surfaces can be completely consumed by thermal expansion, so that components moving relative to one another collide, resulting in considerable damage to the affected high-performance carding machine. Accordingly, particularly the generation of heat in the working region of the carding machine can lead to different degrees of thermal expansion when the temperature differences between the components are too great.
In order to reduce or avoid the risk of collisions, the carding gap between clothings lying opposite to one another is in practice set relatively wide, that is to say a certain safety spacing exists, but a large carding gap results in undesired nep formation in the card sliver. On the other hand, an optimum, especially narrow, dimension, by means of which the proportion of nep in the card sliver is appreciably reduced, is desirable.
In a known apparatus (DE 29 48 825 C), a displacement device actuatable by thermal energy supply is provided for compensating for changes in the carding spacing that arise during operation, at least one adjusting element, for example a rod, cooperating with a fluid, for example oil, and the thermal energy being conveyable to the fluid. For the purpose of effecting the supply of heat by means of a fluid, a protective cover is connected to a fluid supply line and to a fluid discharge line, which open into a container for the fluid. Installed in the fluid supply line is a pump by means of which the fluid can be fed under pressure from the container into the chamber formed round the metal rod by the protective cover. Using a heating device (for example an electrical resistance heating device), the fluid is so heated in the container, to a particular temperature determined by a control means, that the rod is able to expand to a greater or lesser degree. The adjusting devices may comprise a liquid (water, oil) or a gas (for example air), and can effect positioning of the guide bend (flexible bend) on which the ends of the clothed flats slide. In that apparatus, heat thus acts on the liquid, the liquid transfers the heat to a stationary metal rod and the metal rod rotates as a result, the position of the flats, and hence the carding space, being changed by way of the guide bends. A disadvantage is that the heating of metals, both ferrous and non-ferrous, reduces the modulus of elasticity, for example by 20%. Given that the adjusting element is in a resiliently pre-biased state on account of the pre-biasing of the guide bend, additionally compensation for that difference is required, which is of considerable expense in terms of apparatus. A further problem is that a metal rod of a particular length, for example 150 mm, requires a high energy supply, for example heating by about 300°K, to achieve an expansion of, for example, 0.3 mm.
It is an aim of the invention to provide an apparatus of the type described at the outset that avoids or mitigates the mentioned disadvantages and that especially makes it possible, in a structurally simple manner, to keep the carding gap constant or substantially constant.
The invention provides an apparatus at a carding machine having a cylinder with cylinder clothing, working elements, and displaceable holding elements which determine an adjustable space between the cylinder clothing and one or more of the working elements, further comprising:
a displacement device comprising at least one adjusting element for adjusting the position of one or more said displaceable holding elements to compensate for changes in the spacing during operation; and
a fluid that is expansible by thermal energy supply and contractible by thermal energy discharge;
wherein said at least one adjusting element is displaceable by expansion and/or by contraction of the fluid.
The position of the carding elements and thus the size of the carding gap are changed in simple manner because the heat supply brings about positional displacement of the adjusting element, for example rod, by way of thermal expansion of the fluid, for example oil. A particular advantage is that use is made of the expansion of a liquid medium that has a thermal coefficient of expansion higher by a factor of, for example, 100 than that of solids. As a result, in contrast to the known apparatus, a change in temperature of, for example, only 20° K is required to achieve a displacement of about 0.3 mm. A further advantage is that that temperature change is at the components of the carding machine. In that way it is possible to utilise the required thermal energy directly from the components, as a result of which automatic adjustment is effected in the event of changes in temperature of the machine or in the event of changes in the carding gap caused by temperature. Preference is given to the use of a fluid medium that in terms of expansion is correlated with the change in temperature in the carding machine and/or at components of the carding machine. The changes in the carding gap caused by temperature are compensated by that medium.
Advantageously, the fluid is a liquid, which is preferably a non-compressible liquid. Advantageously, the fluid is an oil, especially a hydraulic oil. Advantageously, the coefficient of thermal expansion of the fluid is high, preferably at least
for example, approximately
Advantageously, the change in the carding gap is at least 0.05 mm per 10° K increase in temperature, for example, approximately 0.1 mm per 10° K increase in temperature. Advantageously, the adjusting element comprises a metal rod, a bar or the like. Preferably, the adjusting element comprises a cylinder piston. Advantageously, the displacement device comprises a container, a housing or the like. Advantageously, the adjusting element is attached by one end to the cylinder. Advantageously, the cylinder piston and the region of the adjusting element facing the cylinder piston are arranged in the container, housing or the like. Advantageously, the region of the adjusting element remote from the cylinder piston is arranged outside the container, housing or the like or projects from the container, housing or the like. Advantageously, the fluid is present between the inner wall of the container, housing or the like and at least one end face of the piston. Advantageously, the fluid is present between the inner wall of the container, housing or the like and an end face of the piston. Advantageously, the adjusting element, for example rod, bar or the like, is force-loaded. Advantageously, the adjusting element, for example rod, bar or the like, is spring-loaded, for example, by a compression spring. The spring may be arranged between an end face of the piston and the opposite lying inner wall of the container, housing or the like. Preferably, the container, housing or the like is sealed. Advantageously, the fluid is located in a sealed interior space of the container, housing or the like. Advantageously, the portion of the adjusting element projecting from the container, housing or the like is connected to the carding element. Advantageously, the carding element is locally displaceable together with the adjusting element. Advantageously, the displacement is effected in radial direction in relation to the cylinder. The displacement device may be mounted between the extension bend and a working element, for example carding element. The rod, bar or the like may have an adjusting thread. The displacement device may be mounted between an adjusting spindle (threaded spindle) and a working element. The displacement device may be mounted between an adjusting spindle (threaded spindle) and a flexible bend.
Advantageously, the fluid is in communication with the machine via a heat conduction means or the like. For example, the fluid may be acted upon by the heat of an extension bend; by the heat of a cover element, for example a cover element for the cylinder or a cover element located in the angled gap between two cooperating rollers; or by the heat of a side panel.
There may instead be associated with the displacement device a heating device. The temperature of the heating device is advantageously adjustable. The heating device may be associated with the rod, bar or the like, for example the piston. The heating device may be associated with the fluid or the region of the container, housing or the like enclosing the fluid. Advantageously, the return of the adjusting element (displacement path) is effected by energy discharge from the fluid. The return of the adjusting element (displacement path) may instead be effected by a card flat setting system, for example PFS, or by a card flat measuring system, e.g. FCT.
The working elements may be carding elements, the spacing to be adjusted advantageously being the carding gap between the cylinder clothing and the clothings of the carding elements. The working elements may be clothed rollers, for example lickers-in and/or doffers, the spacing between the clothings of the cooperating rollers, for example cylinder, lickers-in and/or doffers, advantageously being changeable. The working elements may be separator blades for trash or the like.
The invention also provides an apparatus at a carding machine having a cylinder, working elements and displaceable holding elements, which determine the spacing between the cylinder clothing and the working elements, wherein a displacement device actuatable by thermal energy supply is provided for the working elements in order to compensate for changes in the spacing that arise during operation and in which at least one adjusting element, for example a rod, cooperates with a fluid, for example oil, and the thermal energy is conveyable to the fluid, wherein the fluid is expansible by thermal energy supply and/or contractible by thermal energy discharge and the adjusting element is locally displaceable by expansion and/or contraction of the fluid.
The invention also provides a method of adjusting a working gap in a carding machine, comprising providing an adjusting element for positionally displacing a working element defining a limit of said working gap, providing a fluid that is thermally expansible and contractible, and utilising thermal expansion and/or contraction of said fluid for acting on said adjusting element for effecting positional displacement of said working element.
a shows the carding elements according to
In an embodiment of the invention shown in
Carding elements 17′ have, at both of their ends, bearing faces that bear against the convex outer face 19a of the support element. Mounted at the lower face of the carding segment 17′ are carding elements 20a, 20b with carding clothings 20a′, 20b′. Reference numeral 21 denotes the circle of tips of the clothings. The cylinder 4 has at its periphery a clothing 4a, for example saw-tooth clothing. Reference numeral 22 denotes the circle of tips of the cylinder clothing 4a. The spacing between the circle of tips 21 and the circle of tips 22 is indicated by reference letter a and is, for example, 0.20 mm. The spacing between the convex outer face 19a and the circle of tips 22 is indicated by the reference letter b. The radius of the convex outer face 19a is indicated by r1 and the radius of the circle of tips 22 is indicated by r2. The radii r1, and r2 intersect one another in the centre 42 (see
The carding segment 17′ according to
In the embodiment of
According to
A direct heat source (heating spiral) at or in the piston is also possible. The heating operation is controllable and regulatable.
In the arrangement of
In the arrangement of
In the arrangement of
An advantage of the invention is that use is made of a liquid medium that has a coefficient of expansion higher by, for example, a factor of 100 than that of solids. The apparatus requires a temperature change of only 20K to achieve a displacement of about 0.3 mm. That increase in temperature occurs at the components of the flat card. The required thermal energy can be used directly from the components (e.g. MTT shaped cover element at the front, underneath). Required for that purpose is a medium that in terms of expansion is correlated with the change in temperature in the carding machine or at components of the carding machine. The medium must be so selected that it compensates for the changes in the carding gap caused by temperature. With an assumed carding nip change of 0.1 mm per 10K increase in temperature, all that is required is a body 20 mm high filled with hydraulic oil. Hydraulic oil has a coefficient of expansion of 7·10−4/K.
t:=10 K° Temperature difference
γ:=h·γ·t
h:=20 mm Filling height medium
γ=0.140 mm Displacement path
γ:=7·(10)−4K Volume expansion coefficient
Although the foregoing invention has been described in detail by way of illustration and example for purposes of understanding, it will be obvious that changes and modifications may be practised within the scope of the appended claims.
Number | Date | Country | Kind |
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10 2005 052 142 | Oct 2005 | DE | national |
Number | Name | Date | Kind |
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3950822 | Bolli | Apr 1976 | A |
4384388 | Mondini | May 1983 | A |
20060168762 | Tobben | Aug 2006 | A1 |
20060168763 | Tobben | Aug 2006 | A1 |
Number | Date | Country |
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29 48 825 | Dec 1980 | DE |
0 077 166 | Apr 1983 | EP |
0 017 357 | Nov 1984 | EP |
1 231 303 | Aug 2002 | EP |
2 252 482 | Nov 1974 | FR |
2 590 326 | Nov 1985 | FR |
2 850 981 | Feb 2004 | FR |
WO 7900983 | Nov 1979 | WO |
Number | Date | Country | |
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20070119029 A1 | May 2007 | US |