The following specification particularly describes the invention and the manner in which it is to be performed. FIELD OF INVENTION

The present invention relates to an apparatus and method of preservation of animal skins/ hides by lyophilization technology which is techno-economically viable and saves water and chemicals used in the tanning process thereby reducing pollution from tanneries.

BACKGROUND OF THE INVENTION

Tannery sector is cause of considerable environmental pollution, because method of preservation and processing of raw hides/ skins cause severe pollution problem. The wastewater from tanneries are characterized by high total dissolved solids (TDS) concentration due to substantial amount of salt used for curing/ preservation of hides/ skins. Common salt is used to an extent of 50-60% (w/w) for curing of hides/ skins. This generates a huge amount of pollution in the form of total dissolved solids (TDS) and chlorides (CI) during tanning process. This has led to high levels of pollution in groundwater and rivers in India.

The low cost salt preservation method used for curing skins/hides is ultimate cause of pollution due to its high TDS contribution.

Efficiency of biological treatment systems in CETPs and ETPs are affected due to high concentration of TDS in wastewater and sector is treated as nuisance to the society and the environment. High TDS concentration not only inhibits the bacterial growth in the effluent treatment plant but also lyase the bacterial cells thus effecting treatment efficiency of biological systems Disposing salt containing waste water has serious environmental consequences and removing salt from wastewater requires elaborate methods which have their pros and their cons making treatment uneconomical. An alternate method of leather preservation which is practiced in Australia and some European Countries is placing skins/ hides under low temperature from genesis to transportation up to the process of tanning, this is again very energy intensive and practically unachievable due to power shortage and high cost.

Thus there exists a need of a system and method which is techno-economically viable and prevents pollution from the tanneries. A method is needed which prevents TDS in effluent, reduces water and chemical consumption in tannery process thereby reducing pollution from tanneries.

PRIOR ART:

US patent no 4,964,280 relates to an apparatus and method for distillation drying of one or more biological samples. The drying apparatus includes a retaining assembly, a vacuum assembly, cooling means, monitoring means and control means for actively regulating the temperature and pressure conditions of biological tissue so that such tissue may be dried without substantial ultrastructural damage. This patent talks about the apparatus of cryopreparation of biological tissue samples for ultrastructural analysis.

US patent no 5948144 relates to the apparatus and methods for lyophilization of protein and/or pharmaceutical products, wherein said apparatus utilizes a dry vacuum pump for the direct removal of water vapor, rather than a cold trap condenser. A freeze dryer has a vacuum pump which is connected directly to a drying chamber without the use of a cold trap condenser. The exhaust of the vacuum pump is vented directly to atmosphere. Water vapor generated in the process is directly removed from the chamber by the vacuum pump.

US patent no 6684524 relates to a lyophilization method which comprises the following steps: reducing the pressure in the drying chamber until the onset of a visible crystallization of the solvent at a temperature m toe drying cnamDer which is above the solidification point of the preparation; reducing the temperature in the drying chamber to a temperature which is below the solidification point of the preparation or is identical to it, until completion of the crystallization of the solvent, resulting in a frozen solvent; and sublimation of the frozen solvent by means of reduced pressure.

US patent no 6226887 relates to the freeze drying apparatus and associated lyophilization procedures employing vapor flow detection and/ or vacuum control for monitoring and control of the lyophilization process. The vapor flow detector, such as a windmill sensor, is disposed to monitor vapor flow from product undergoing lyophilization.

US patent no 5,199,187 relates to a freeze dryer apparatus having an interim condensing system, preferably a refrigeratable condensing surface. The interim condensing system condenses vapors within the product chamber of the freeze dryer apparatus when the main condenser coil, which normally condenses vapors within the product chamber, needs to be defrosted. The refrigeratable condensing surface is preferably mounted inside the product chamber.

US patent no 4,547,977 relates to temperature control systems for freeze dryers. The microcomputer is programmed to both monitor and control the freeze drying process. The microcomputer reads a pressure sensor to ensure that the desired level of vacuum is obtained. Also, the microcomputer turns on the vacuum pump, the refrigerator, and the circulation pump at the required times in the cycle. In order to check that the desired temperature are obtained in the vacuum chamber, a product shelf temperature sensor senses the temperature of the heat transfer fluid being circulated to the shelf assembly. US patent no 5,024,830 relates to apparatus for the cryopreparation of biological tissue samples for ultrastructural analysis. The use of the apparatus comprises vitrifying a biological tissue sample under cryogenic temperature conditions and ultra low vacuum conditions. The depressurized, vitrified tissue sample is brought to equilibrium in a sample holder at a temperature of less than -140.degree. C. The tissue sample is then dehydrated while maintained in a state of thermal equilibrium. After reaching equilibrium the tissue sample is optionally infiltrated with a degassed resin followed by a polymerization of the resin to form an embedded tissue sample. This patent talks about the concept of cryopreparation of biological tissue samples for ultrastructural analysis

US patent no 4,676,070 relates to method and apparatus for the cryopreparation of biological tissue samples for ultrastructural analysis. The use of the apparatus comprises vitrifying a biological tissue sample under cryogenic temperature conditions and ultra low vacuum conditions. The depressurized, vitrified tissue sample is brought to equilibrium in a sample holder at a temperature of less than -140. degree. C. The tissue sample is then dehydrated while maintained in a state of thermal equilibrium. After reaching equilibrium the tissue sample is optionally infiltrated with a degassed resin followed by a polymerization of the resin to form an embedded tissue sample. This patent talks about the concept of cryopreparation of biological tissue samples for ultrastructural analysis

US patent no 5,884,414 relates to a freeze dryer which has a housing defining a chamber. A condenser is remote from the chamber and has an interior coupled for communication with the chamber. A base supports the chamber and is configured to accommodate the chamber in a plurality of different positions relative to the base. A pump is coupled to the chamber to lower pressure in the chamber.

US patent no 6,122,836 relates freeze drying apparatus and associated lyophilization procedures are provided employing vapor flow detection and/or vacuum control for monitoring and control of the lyophilization process. The vapor flow detector, such as a windmill sensor, is disposed to monitor vapor flow from product undergoing lyophilization.

US patent no 4,197,658 relates to a freeze dryer for rapidly and efficiently drying tissue specimens, having a source of heat independent of the cover and mounted for efficient heat transfer to a copper support plate having a substantially flat top surface. A specimen plate is machined from aluminum to have a recessed bottom surface which is matable with the support plate for maximum physical contact. The specimen plate has peripheral walls of a thickness and a height that will eliminate substantially all heat differentials between different portions of the specimen plate interior caused by external variations to allow effective control of the temperature of the specimen plate.

US patent no 4,017,983 relates to a freeze drying apparatus of the manifold type having a generally horizontal free standing condenser tube enclosed within a removable hollow manifold having a plurality of ports formed in it for communication with the interior of containers having specimens to be sublimated. The condenser tube is disposed generally along the central axis of the manifold so that the distance between the condensing surface and the manifold ports is relatively short and constant to provide fast and uniform sublimation. The condenser tube is packed with a woven copper mesh to provide increased surface area for wetting by the refrigerant fluid thereby increasing the condenser capacity and reducing its temperature.

OBJECTS OF THE INVENTION

A primary object of the present invention is to provide a method and apparatus for curing of raw animal skins and hides for preservation for transportation to tannery industries. 10 000770

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Another object of the invention is to provide a method and apparatus which is long lasting, techno-economically feasible and prevents pollution.

Still another object of the invention is to provide a method and apparatus which helps in improving the efficiency of biological treatment systems in CETPs and ETPs.

Another object of the present invention is to provide a system of immobile unit for organized slaughter houses.

Still another object of the present invention is to provide an apparatus of mobile unit for unorganized slaughter houses/ meat shops/ dead animals.

Another object of the invention is to provide an apparatus which is designed for skins of different animals to be lyophilized.

Yet another object of the invention is to provide an apparatus which can be used irrespective of type of skins/ hides.

STATEMENT OF INVENTION

According to this invention there is provided an apparatus for curing of raw animal skins and hides for preservation for transportation to tannery industries comprising a lyophilizer having a drying chamber, suction pipe or pipes disposed within said chamber and connected to condenser for trapping water vapours formed in the drying chamber and a vacuum pump a frame disposed within said chamber and having means for hanging the skins and hides.

The present invention provides method and system for curing of raw animal skins and hides for preservation for transportation to tannery industries. Lyophilizer apparatus includes (i)drying chamber for drying skins/hides (ii) rectangular frame with bars/ hangers for hanging animal skins/hides each capable to hold skins/ hides of weight ranging from 2 to 20 kg (iii) Ice condenser for trapping water vapor formed during the process (iv) vacuum pump. The apparatus is designed with in-built weighing facility to record the weight loss of the product during the lyophilization process, which is indicative of degree of lyophilization. This helps in mamtaining the required degree of lyophilization depending on the period of preservation required, which is an energy and time saving parameter. The drying chamber is equipped with multiple suction points to ensure uniform drying. Accelerated freeze drying facility is provided in the drying chamber for quick and efficient drying of skins/ hides.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:

Fig 1 shows: block diagram of the lyophilizer according to the present invention. Fig. 2 shows: flowchart according to the present invention.

DETAIL DESCRIPTION WITH REFERENCE TO ACCOMPANYING DRAWINGS

Reference may be made to fig 1 which shows block diagram of the lyophilizer according to the present invention. The present invention provides method which is designed for curing hides and skins for preservation for transportation to tannery industries using lyophilization technology.

The system comprises a cylindrical shape drying chamber (1) made up of material such as but not limited to the stainless steel with a viewing facility made up of Perspex so that the operator/ user can see from the outside. The drying chamber (1) is provided with a thermal sensor to sense the product temperature and multiple suction points (2). Multiple suction points are provided within the drying chamber to ensure uniform drying. The chamber is provided with accelerated freeze drying facility (hot air circulation system) for quick and efficient drying of skins/ hides.

Removable rectangular frame (3) in two tier system (4) with hanging bars/ rods (5) each capable to hold the skin/ hides (6) of weight 0- 20 kgs is housed in drying chamber.

The drying chamber is provided with a load cell facility (7) for recording the weight loss of the product placed in the drying chamber.

The Multiple suctions (2) in the drying chamber (1) are connected to an ice condenser (8) with manifold capable to reach -75 degree to -80 degree C. Chlorofluoro carbon free refrigerants are used in condenser. The condenser is made of material such as but not limited to the stainless steel non magnetic, argon welded collector coil of varying capacities to trap water vapor formed during sublimation.

Condenser is connected to two stage vacuum pump (9) based on the level of vacuum pressure required. In-built auto start facility is provided for operation of vacuum pump. First pump having higher capacity operates until temperature of condenser reaches -80 degree centigrade. Second pump of relatively lower capacity starts automatically after temperature of condenser reaches - 80 degree centigrade.

Lyophilizer contains a microprocessor (10) to handle the internal functions of the lyophilizer which is displayed in control panel (11). The wiring is centrally located at the back panel of the system which is connected to the main supply. A metering unit (12) is attached to the supply which will continuously monitor the amount of energy used by the system. Replaceable connectors are used for wiring an electrical load. Generators or power backup systems can also be attached to the system for operating lyophilizer in case of power failure. The whole system is mounted on the frame with wheel so that it can be easily moved to any location.

During process of lyophilization, more energetic molecules escape and the temperature of the product falls by evaporative cooling and moisture within the product is frozen which is sublimated to water vapor and condensed in ice condenser. The temperature of the sample will then continue to fall below the freezing point and sublimation will slow down until the rate of heat gain in the sample by conduction, convection and radiation is equal to the rate of heat loss as the more energetic molecules that sublime away are removed.

The lyophilization process involves the following steps-

• Skins/ hides are required to be lyophilized within few hours of slaughtering

• Flayed skins/ hides are placed on bars of rectangular frame (3).

• Rectangular fame is placed inside the drying chamber and door is closed (4).

• Pressure release valve (13) and water drain valve (14) are closed.

• Pump and related indicators (temperature, weight,) are switched ON.

• First pump operates until temperature of the condenser reaches - 80 degree centigrade. Second pump starts automatically after temperature of condenser reaches -80 degree centigrade.

• The lyophilization / drying process is continued until the weight of skins/ hides are reduced by 50 % which indicates 100% lyophilization.

• Pump (9) and related accessories are switched OFF. Rectangular frame (3) is taken out and skins/ hides are removed from the bars (5) which is ready for transportation to tannery units.

Skins/ hides can be preserved for more than 20 days.

Different systems are designed for different sector of slaughter houses i.e., organized, unorganized/ meat shops/ dead animals. Fixed lyophilization system for organized houses and mobile system for unorganized slaughter houses for curing skins/ hides at distant places and a system based on the skin of different animals (sheep, baffallo, goat).

Experiments have been conducted with formaline, distilled water treatment followed by lyophilization, tap water treatment followed by lyophilization, alcohol treatment followed by lyophilization in order to assess the feasibility in terms of cost effectiveness, pollution load and reduction of wastewater.

It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-