Title of Invention

AN IMPROVED MECHANISED PULSE DEHUSKER

Abstract

An improved mechanized pulse dehusker for preparing dry as well as wet pulses characterized in that, it comprises an enclosure, (B) consisting of a top and bottom open truncated cone shaped wire mesh cage (H) having inside it a concentrically placed rotatable truncated abrasive coated cone (G), having a base angle between 61 to 80°, the said coated cone being fixed a top a vertical shaft capable of providing vertical movement (D), the said vertical shaft being ratatably fixed on to a support structure (F) by conventional means, and coupled by conventional means to a prime mover (E), the said enclosure (B) being fixed onto the said support structure (F) and provided at its top and bottom with a feed hopper (A) and discharge chute (C) respectively.

Full Text

The present invention relates to development of an improved mechanised pulse dehusker. India is one of the major producers of pulses in the world contributing about 25% of the total world production. Apart from common pulses like Bengal gram, tur (red gram), green gram and black gram, a good number of other pulses such as cowpea, kidney beans, horse gram, lentil, moth bean etc. are also produced and consumed in different regions of the country. The annual production of pulses is about 15 million tonnes and generally they are consumed in a variety of food products after conversion into dhal i.e. dehusked and split pulse. Conversion of pulses to dhal is the third largest food processing industry after rice and wheat. It is estimated that more than 75% of the pulses produced are converted into dhal. The operation of milling pulses consists of two major steps: 1. Loosening of the husk from cotyledons. 2. Removal of husk followed by splitting into two cotyledons. The first step of loosening of husk is achieved by suitable pre- milling treatments (either wet or dry method) while its removal (second step) is done using contrivances/machines like chakki under - runner disc sheller, cone polisher, emery roller etc.. depending on the scale of operation and the type of pulse. Dhal milling is being practiced in India since centuries. Traditionally pulses are either soaked in water for some period, and then sun-dried (wet method) or given a "pitting1 - oiling-watering-sun-drying treatment (dry method) prior to milling. These operations were carried out in rural areas in home or cottage scale in earlier days. The loosened husk was removed using chakki. dhenki or pestle and mortar. With the advent of the technology, the premilling treatments (dry method) and subsequent milling of pulses were carried out in large scale using emery rollers, under runner disk shellers or similar machines. Large scale dhal milling industries need huge capital investment, power and raw material to gain economic viability while small scale or tiny scale units produce inferior quality product with lesser yield compared to large scale dhal mills. With the establishment of large scale dhal mills the village level processing units are almost extinct since they were not able to compete with large scale dhal mills in terms of yield and quality of dhal. In order to revive this village level pulse processing industry Central Food Technological Research Institute, a constituent laboratory of Council of Scientific and Industrial Research, New Delhi, India has earlier developed hand-operated pulse dehusker and a motorised version of the same to replace wasteful chakki. dhenki, or pestle and mortar. Reference may be made to the following: 1. Published paper entitled, " A hand operated small scale pulse dehusking machine, for rural use" by P.P. Kurien & B.S. Patil, in Research and Industry, India, vol.34, No.3, page 213-216 (1989) . 2. Published article entitled "Dhal processing technology by CFTRI, a boon to pulse growers and processers", by P.P. Kurien and P.S. Balakrishna, in Fusion Asia, (1991), page 36- 38. The units so described in the above publications work on abrasion principle and essentially consist of an emery coated cone rotating inside a wire mesh cage. The angle of the emery coated cone of hand operated unit is 45° J while that of motorised version of the pulse dehusker is 60°. j These units can process 50-100 kgs of conditioned pulse per hour. Although these units are popular with village level processors they have got their own limitations. One of the major draw back is that they can process only wet preconditioned pulse and are 1 suitable for processing of bolder grains like tur, Bengal gram and peas only. A survey conducted earlier has revealed that there has been a persistent demand from dhal processors to improve the traditional roller machine or develop an intermediate / medium capacity dhal mill / dehusking unit which will dehusk almost all pulses efficiently and will be economically suitable for small / medium scale dhal processors. The present machines either give excessive scouring leading to both qualitative and quantitative loss or do not give fully dehusked product which leads to poor market value of the product. There is an urgent need to improve upon the existing machines or develop a new one which give fully dehusked product with least powder loss. The premilling treatment to be given to the pulses should also be easily adaptable and not very specific or critical. The main object of the present invention is to provide an improved mechanised pulse dehusker which obviates the drawback as detailed above. Another object of the present invention is to provide a device to produce well dehusked product such as Dhal. Still another object of the present invention is to provide low powder loss. Yet another object of the present invention is to provide processing facility for all types and sizes of pulses. Still another object of the present invention is to provide dehulling of pulses preconditioned either by wet or dry method. In Fig 1,2 & 3 of the drawings accompanying this specification, the schematic diagram of the various parts of the improved mechanised pulse dehusker of the present invention is shown: A. Feed hopper, B. Components (G&H) of dehusking device enclosed in an outer cover. C. Discharge chute for mill-stream D. Vertical shaft E. Prime mover for driving the device. F. Support structure for whole assembly G. Truncated emery coated cone H. Wire mesh cage Accordingly, the present invention provides an improved mechanized pulse dehusker for preparing dry as well as wet pulses characterized in that, it comprises an enclosure, (B) consisting of a top and bottom open truncated cone shaped wire mesh cage (H) having inside it a concentrically placed rotatable truncated abrasive coated cone (G), having a base angle between 61 to 80° , the said coated cone being fixed a top a vertical shaft capable of providing vertical movement (D), the said vertical shaft being ratatably fixed on to a support structure (F) by conventional means, and coupled by conventional means to a prime mover (E), the said enclosure (B) being fixed onto the said support structure (F) and provided at its top and bottom with a feed hopper (A) and discharge chute (C) respectively. In an embodiment of the present invention the abrasive coating used may be such as emery, silicon carbide grits. In another embodiment of the present invention, the prime mover used may be such as an electric motor, internal combustion engine. The conditioned pulse / grains are fed into the hopper (A), which rolls down to dehusking device (B) consisting of a truncated emery coated cone (G) fixed to a vertical shaft (D) , rotating inside a wire mesh cage (H) and powered by a 3 HP motor (E) the mill-stream consisting of dehusked pulses, dhal, husk and i powder comes out through discharge chute (C) which is separated subsequently. The whole assembly is mounted on a firm support structure (F) of MS channels and angles which gives no vibrations or noise. The dehusker is having a capacity to process about 250 - 300 kgs of pulses per hour: The improved mechanised pulse dehusker of the present invention may be used as follows: Cleaned and size graded raw pulse is given a dry pre-milling treatment consisting of (i) scarification of the husk (ii) addition of adequate quantity of oil for the pulse followed by mixing and equilibration (iii) drying for 2-3 days (iv) addition of adequate quantity of water followed by drying. The pretreated pulse is then dehusked and split in the said improved mechanised pulse dehusker to get dhal. The following examples are given by way of illustration and should not be construed to limit the scope of the present invention. The performance of the machine of the present invention having emery coated cone with base angle more than 60° was tested by milling different varieties of all major pulses (tur, Bengal gram, green gram, and black gram). EXAMPLE 1 A Variety of tur was processed to dhal using this dehusker (3 batches of 50 Kg each) . First the material was cleaned and graded using a precleaner - grader consisting of suitable sieves. The major fraction of material was given a pretreatment generally followed by dhal millers i.e. scarification of husk, oiling, sun-drying, watering and sun-drying again. The material is milled in the above mentioned dehusker with a emery coated cone having base angle 70° at peripheral speed of 1200 mts/min. Yield of dhal obtained was 78% (on cleaned and graded materials basis) with 99% dehusking. EXAMPLE 2 A local variety of Bengal gram was given a premilling treatment consisting of scarification of husk, water addition, holding t overnight and sun-drying for 1-2 days. 50 Kgs batches -3 Nos. were processed to dhal using this machine, (having a emery coated cone with base angle 80º) the yield of dhal obtained was 79% (cleaned, graded raw material basis) with 99.5% dehusking. EXAMPLE 3 Locally available variety of black gram was cleaned, graded, in precleaner cum grader and given the traditional pretreatment consisting of scarification of husk, oiling, sun-drying, watering and sun-drying 'again. The materials when milled in the dehusker (having a cone with base angle 65°) has given a dhal yield of 77% with 99.5% dehusking. EXAMPLE 4 3 batches (50 Kgs each) of clean Green gram were given a pretreatment consisting of scarification of husk, oiling, holding overnight, sun-drying, watering and sun-drying . When pretreated material is milled in the dehusker, (having a cone with base angle 80°) a dhal yield of 76% with 99.5% dehusking is obtained. The main advantages of the present invention are: 1. It can process all types and sizes of pulses. Even smaller t quantities (eg. 100 gm) could be milled while the traditional machine of similar capacity need at least 5 Kg material. 2. Gives 2-4% higher yield of dhal than the traditional machines. 3. Gives 98-99.5% dehusked dhal. 4. Suitable for milling of both dry and wet pre-conditioned pulse. We claim: 1. An improved mechanized pulse dehusker for preparing dry as well as wet pulses characterized in that, it comprises an enclosure, (B) consisting of a top and bottom open truncated cone shaped wire mesh cage (H) having inside it a concentrically placed rotatable truncated abrasive coated cone (G), having a base angle between 61 to 80° , the said coated cone being fixed a top a vertical shaft capable of providing vertical movement (D), the said vertical shaft being ratatably fixed on to a support structure (F) by conventional means, and coupled by conventional means to a prime mover (E), the said enclosure (B) being fixed onto the said support structure (F) and provided at its top and bottom with a feed hopper (A) and discharge chute (C) respectively. 2. An improved dehusker as claimed in claim 1, wherein the abrasive coating used can be emery, silicon carbide grits. 3. An improved dehusker as claimed in claim 1, wherein the prime mover used can be an electric motor, internal combustion engine. 4. An improved mechanized pulse dehusker substantially as herein described with reference to the examples and drawings accompanying the specifications.

Documents:

2385-del-1998-abstract.pdf

2385-del-1998-claims.pdf

2385-del-1998-correspondence-others.pdf

2385-del-1998-correspondence-po.pdf

2385-del-1998-description (complete).pdf

2385-del-1998-drawings.pdf

2385-del-1998-form-1.pdf

2385-del-1998-form-2.pdf

2385-del-1998-form-3.pdf