Classifications

• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14B—MECHANICAL TREATMENT OR PROCESSING OF SKINS, HIDES OR LEATHER IN GENERAL; PELT-SHEARING MACHINES; INTESTINE-SPLITTING MACHINES
  • C14B1/00—Manufacture of leather; Machines or devices therefor
  • C14B1/58—Drying

Definitions

• the invention relates to a method for heat treatment, in particular for conditioning, in particular for drying and / or moistening, leather, furs, furs and the like.
• the invention further relates to a device for carrying out such a method.
• certain configurations are also suitable for use in the treatment of other soft-flexible flat materials.
• "Conditioning" in tannery and leather processing generally means the setting of certain desired properties of leather or skins, furs and furs through the targeted action of ambient conditions such as temperature, humidity and pressure of the air, gas and the material to be treated. or steam atmosphere as well as by exposure to energy radiation.
• the deformation properties (flexibility, extensibility and the like) and surface properties of the material, as well as other material properties that are important for processing are dependent on the moisture content.
• the object of the invention is therefore to create methods and devices which allow progress in relation to the known in terms of effectiveness, reproducible property setting in the material to be treated or performance.
• the solution to this problem is characterized in terms of the method and the device by the features of the independent claims.
• the features of these claims can be used with particular advantage in a mutual combination, but can also be used progressively, if necessary.
• FIG. 1 shows a schematic vertical section with a block circuit of a first embodiment of a drying device for a method according to the invention
• FIG. 2 shows a representation corresponding to FIG. 1 for a second embodiment of a drying device according to the invention with an illustration of a further method according to the invention for conditioning leather and the like
• FIG. 3 shows a schematic horizontal section with a block circuit of a third embodiment of a device according to the invention for conditioning leather and the like
• FIG. 1 shows a schematic vertical section of a treatment device according to the invention with a movable treatment goods receiving device
• FIG. 5 shows a sectional view corresponding to FIG. 4 of the material to be treated
• FIG. 7 shows a sectional view corresponding to FIG. 5 for a further embodiment of a material to be treated
• FIG. 8 shows a vertical section of the receiving device according to FIG. 7 rotated at a right angle
• FIG. 10 shows a section of a side wall of the treatment chamber according to FIG. 9 with a triangular microwave transmitter arrangement
• FIG. 11 shows a partial vertical section of a material to be treated with a moisture sensor.
• a vacuum-proof and vacuum-tight treatment chamber BK1 with connection to a vacuum system UA is provided.
• a receiving device AVI for leather, furs, furs or the like designed as a rotating conveyor belt, which is located on the upper strand of the conveyor belt and is arranged in an alternating electromagnetic field between large-area plate electrodes EL.
• the electrodes EL are connected to a high-frequency power generator HFG, which operates in a frequency range between approximately 10 and 300 MHz.
• a relatively strong negative pressure is generated in the chamber BK1, which is not only sufficient to extract the water vapor produced, but also however, the evaporation temperature of the water contained in the leather or the like is substantially reduced, preferably to a maximum of about 700 ° C., with particular effectiveness with regard to an additional flexibility of the leather due to cellular explosive effects during water evaporation, in particular up to about 50 ° C. and below.
• a chamber pressure of 0.7 bar to approximately 0.6 bar has been found for conditioning leather for lighter and more porous types of leather and furs and furs with a large specific surface area, but for heavier types of leather a chamber pressure of approximately 0.6 bar to approximately 0. 5 bar and below proved to be advantageous.
• the lower pressures greatly promote flexibility.
• the relatively low treatment temperature also improves the uniformity of the drying process and favors precise process control with a reproducible completion of the drying process, whereby embrittlement can be avoided by falling below the optimum moisture values of the leather.
• Fig.l Another essential property of the device according to Fig.l is the possibility of periodic directional switching u according to arrow P1 des (not shown) To achieve treatment goods within the high-frequency field. This results in an advantageous compensation of inhomogeneities in the high-frequency field that can never be completely avoided in practice, ie an essentially uniform heating of all areas of the material to be treated.
• the device according to FIG. 2 is distinguished by the novel combination of the use of microwave fields with the application of negative pressure to leather and the like for drying or conditioning and flexibilization.
• microwave generators MWG which are arranged at the treatment chamber BK2
• the heating takes place essentially by absorption of the microwaves in the water-containing micro-areas (pores, cells) of the material, the progressive drying with decreasing water content automatically slowing down the speed of the drying process.
• This advantageously reduces the risk of the leather over-drying and overheating, especially in connection with the effects of the negative pressure on the material to be treated, which have already been explained.
• the ranges already given apply to the preferred negative pressure values.
• a frequency range from about 0.3 to about 30 GHz can be considered for drying and conditioning leather, furs and furs with microwaves.
• frequencies between approximately 1.2 and approximately 2.8 GHz have proven to be particularly advantageous for lighter types of leather and furs, but those between approximately 18 and 30 GHz have proven particularly advantageous for heavier materials.
• the material to be treated receiving device AV2 is designed to be rotatable about a vertical axis X and is provided with a corresponding rotary drive DA, so that the movement path of the material to be treated passes through the inhomogeneous parts of the energy field.
• microwave coupling-in devices or radiators STR are arranged on a treatment chamber BK3 and are distributed over a periodically acting one Switches SV are connected in a predetermined sequence to a microwave power generator MWG and are thus activated.
• a corresponding mechanical coupling valve switchover in connection with waveguides or on the radiators themselves in analogy to the switchover schematically indicated as an example, and also a successive switch-on or activation of a plurality of generators can be used, which none requires special presentation.
• feeds WDS with distribution nozzles DS for floating water or steam are also arranged in a distributed manner in the treatment chamber, as shown in FIG. This means that the material to be treated can be moistened or rewetted afterwards or alternately with drying. This is not only advantageous for setting exact humidity values, but also for special interactions.
• a treatment chamber BK4 with a retractable and extendable receiving device AV4 is provided, which is designed with a front wall section FA and a bottom section BA of the chamber as supporting elements to form a structural unit.
• Fig.4 shows the one Chassis FW provided and in the extended state independent of the chamber movable unit of the receiving device in the operating state within the chamber, a gapless seal 2 allows the vacuum to be applied to the chamber.
• a vacuum system with pump 7 and boiler 6 is provided for this.
• Connections 8 and 9 are intended for humidification using water or steam.
• heating or drying air can be fed via a connection box 3 and the support elements 10, which are designed, for example, as pipes with outlet openings 11, to the receiving device AV4, on which the material to be treated BG hangs (see FIG. 6).
• a switch S4 which is automatically activated when the receiving device is moved into the chamber ensures that the microwaves provided here (in a manner not shown in detail) as heating energy are switched on. This is essential for occupational safety.
• FIG. 8 and 7 show a similar treatment item receiving device AV5 with horizontal plate elements 12 as a support for leather and the like.
• Movable receiving devices of the type shown can be 'due to the inclusion of chamber wall elements' simply design it with great robustness and drive it into the chamber in an easily fitting manner. Above all, a suitable number of movable receiving devices assigned to each chamber enables efficient battery operation.
• the treatment chamber 100 shown in FIG. 9 is provided with a loading opening 101 which extends essentially over the entire front side and which can be closed by a double-leaf door 102.
• the loading ie loading and unloading of leather pieces hanging on rod-shaped holders 104 105, takes place in the direction of the arrow 106.
• the brackets 104 - as shown, for example, in the above-described embodiments - are combined with support and guide elements (not shown here in more detail) to form a movable receiving device.
• multiple microwave transmitter arrangements 107 are provided on both side walls of the chamber.
• This diametrical transmitter arrangement favors the desired, approximately homogeneous distribution of the energy field or of the temperature field in the chamber that arises from absorption.
• the radiating elements 108 of the microwave transmitters open directly into the treatment room, that is to say without intermediate coupling elements, which not only leads to a comparatively simple and inexpensive construction, but in particular also facilitates the setting of predetermined field distributions in the chamber. - ⁇ 2 - -
• the areal, grid-like distribution of the radiation elements 108 within the chamber side walls is particularly effective here. This results in the possibility of an optimal approximation to the desired homogeneous field distribution, as detailed measurements and examinations of different arrangements and distributions have shown.
• the transmitters are distributed over the circumference of a raster element or stripping elements can be controlled or synchronized with a phase shift corresponding to their angular displacement on the raster element circumference, ie uniformly distributed in the example, the formation of a resulting field vector 109, which, for example, as a rotating field vector revolves in the direction of arrow 110.
• a resulting field vector 109 which, for example, as a rotating field vector revolves in the direction of arrow 110.
• low-frequency modulation or keying of the transmitters with a corresponding phase shift can also be considered.
• the transmitters must be synchronized.
• the circumferential field vector causes the absorption and heat development to be evened out, in particular also with the compensation of existing inhomogeneities in the distribution of the absorption capacity of the material to be treated.
• the device according to Fig. 9 is for a drying operation ongoing moisture measurement provided on the leather pieces 105.
• moisture sensors 111 arranged in the rear wall of the chamber are used, which can be adjusted by means of double-acting adjusting cylinders 112 which can be reversed at predetermined intervals between a measuring position with touching the rearmost piece of leather and a rest position without touching the leather.
• This procedure and the corresponding measurement arrangement has the advantage that the electrically conductive and therefore wave-absorbing probe tips only come into contact with the leather for a short time and therefore a locally concentrated heating of the leather which influences the moisture measurement is kept low with correspondingly increased drying .
• the arrangement allows continuous monitoring of the moisture status in the leather and thus an end to drying when the desired residual moisture has been reached, ie the desired moisture value.
• Such a procedure was previously not possible, which is why laborious rewetting of the leather had to be carried out after drying.
• the arrangement of a plurality of sensors distributed over the leather surface also allows the spatial uniformity of the leather moisture to be checked.
• the number of measuring sensors with associated actuating and control devices of a known type can be increased significantly, if necessary , compared to the example shown.
• averaging is advantageously used to represent the overall drying process, possibly also an extreme value means of checking for excessive irregularity. -ij.
• the rod-shaped part 113 advantageously consists of a relatively absorbent material, for which a large number of known plastics are available.
• the ability to adapt is still chosen so that it lies in the range of the desired leather quality, taking into account the realities. Since, therefore, a certain electrical conductivity region of the leather pad n be permitted even desirable or even the arrangement comes from permanently with the leather in • duction standing humidity sensors in the field of Lederauf-; e into consideration, provided that the measurement electrodes 114 of suitable -teckstoff or the like.
• a moisture determination according to the method known per se is required for the conductivity measurement of the material to be dried.
• the breathable moisture measurement thus also made possible for microwave heating obviously offers great advantages in terms of measurement and control and also a simplification of the measurement order in terms of construction.
• the loading opening 101 is provided with a closed hose seal 115, which extends along the opening edge, the inner space of which is filled with a highly absorbent medium, advantageously a liquid corresponding to conductivity.
• a highly absorbent medium advantageously a liquid corresponding to conductivity.
• Shaft sealing is characterized by high effectiveness with a simple and robust construction, furthermore by high deformability and thus adaptability to large dimensional deviations between the parts to be sealed against one another.
• Another important property of these microwave seals according to the invention is the heating and expansion of the medium or of the liquid in the case of coarse leaks in the mechanical shielding elements, such as door rebates and the like, which are usually connected upstream of the microwave space namely, increased pressure and penetration into the abnormally enlarged sealing gap, which is a very desirable emergency sealing property.
• the expansion of the absorption medium in the enveloping element, in particular in the hose, of the seal can also be used to detect an abnormal increase in the microwave energy, the sealing element taking over a sensor function.
• the content expansion can be conveniently brought to conversion into a suitable measurement or monitoring signal via a pressure sensor which is conventional per se.
• a microwave leak detector 116 of the same kind is provided in the example with a liquid-filled hose, which extends in a frame-like manner over both wings 103 of the door 102 and is connected to two expansion detectors 117 - one for each door wing.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Drying Of Solid Materials (AREA)
• Treatment And Processing Of Natural Fur Or Leather (AREA)
• Constitution Of High-Frequency Heating (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=6273082

Family Applications (1)

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• 1985
  • 1985-06-12 DE DE19853521061 patent/DE3521061A1/de not_active Withdrawn
• 1986
  • 1986-06-11 CS CS864327A patent/CS432786A2/cs unknown
  • 1986-06-12 DD DD86291243A patent/DD246122A5/de not_active IP Right Cessation
  • 1986-06-12 JP JP61503432A patent/JPS62503104A/ja active Pending
  • 1986-06-12 EP EP86903375A patent/EP0225355A1/de not_active Withdrawn
  • 1986-06-12 ES ES555993A patent/ES8800990A1/es not_active Expired
  • 1986-06-12 BR BR8606726A patent/BR8606726A/pt unknown
  • 1986-06-12 WO PCT/EP1986/000350 patent/WO1986007389A1/de not_active Application Discontinuation
• 1987
  • 1987-02-10 KR KR870700116A patent/KR880700083A/ko not_active Application Discontinuation
  • 1987-02-11 SU SU874202017A patent/SU1588267A3/ru active
  • 1987-02-11 FI FI870563A patent/FI870563A0/fi not_active Application Discontinuation
  • 1987-02-12 US US07/013,737 patent/US4856201A/en not_active Expired - Fee Related
  • 1987-08-31 ES ES557704A patent/ES8800991A1/es not_active Expired

Non-Patent Citations (1)

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