Left: Urschel Model G-A dicer, strip cutter and slicer Right: Urschel ModelJ9-A Left: Urschel Model RA-A for small to intermediate sized dices strip cuts and slices Right: Urschel Model wvF bean slicer
Left: Urschel Model G-A dicer, strip cutter and slicer Right: Urschel Model J9-A two dimensional dicer Left: Urschel Model RA-A for small to intermediate sized dices, strip cuts and slices Right: Urschel Model WVF bean slicer 4
〔h) Bean Snipper This is a revolving drum with perforated slots around the periphery. Knives are positioned to cut along the whole length of the drum, the cutting edge being set almost up to the drum surface The beans tumble around as they pass through the inside of the ylinder and, in course of travelling along its whole length, the ends project through the slots and are cut off by the knives Most modern snipers are continuous in action rather than batch fed and any unsnipped beans at the discharge end are returned to the feed end or, in the case of high capacity throughput, to a second machine in the line PEELERS There are basically four methods of peeling potatoes and root (1) Lye peeling )Steam peeling (3)Combination of heat and lye; (4)Abrasive peeling, either batch The dehydrator will have to decide which method suits his circumstances, and with due consideration to the effect of the method chosen on the effluent problem, which can, of course, be aggravated by one or other of these methods. Provided that the effluent problem has been taken care of, and that suitable treatment has been organised, the preference will usually lie between steam or lye peeling, and the advantages and disadvantages of both methods can be summarised as follows (1) Lye Peeling One of the main advantages is the relatively low capital cost of the equipment, as it is quite usual for lye peelers to be fabricated from mild steel, no particular advantage being obtained by using stainless steel. The design is basically simple, usually consisting of a perforated metal drum, with pockets into which the vegetables are fed, rotating in a bath of hot lye(sodium hydroxide) solution of 5-20 percent concentration, according to the peeling characteristics of the vegetables being handled Maintenance costs are low, as there are few moving parts in the machine The system is capable of a wide variation in peeling technique to suit any particular type of raw vegetable. Some processors use the thermal shock method of high concentration and temperature, with short immersion time, whereas others prefer a lower concentration of lye and longer dwell time. In some cases, wetting agents are used in the lye tank, to cut down the usage of
01) Bean Snipper This is a revolving drum with perforated slots around the periphery. Knives are positioned to cut along the whole length of the drum, the cutting edge being set almost up to the drum surface. The beans tumble around as they pass through the inside of the cylinder and, in course of travelling along its whole length, the ends project through the slots and are cut off by the knives. Most modem snippers are continuous in action rather than batch fed, and any unsnipped beans at the discharge end alr? returned to the feed end or, in the case of high capacity throughput, to a second machine in the line. PEELERS vegetables: There are basically four methods of peeling potatoes and root (1) Lye peeling; (2) Steam peeling; (3) Combination of heat and lye; (4) Abrasive peeling, either batch or continuous. The dehydrator will have to decide which method suits his circumstances, and with due consideration to the effect of the method chosen on the effluent problem, which can, of course, be aggravated by one or other of these methods. Provided that the effluent problem has been taken calr? of, and that suitable treatment has been organised, the preference will usually lie between steam or lye peeling, and the advantages and disadvantages of both methods can be summarised as follows: (1) Lye Peeling One of the main advantages is the relatively low capital cost of the equipment, as it is quite usual for lye peelers to be fabricated from mild steel, no particular advantage being obtained by using stainless steel. The design is basically simple, usually consisting of a perforated metal drum, with pockets into which the vegetables are fed, rotating in a bath of hot lye (sodium hydroxide) solution of 5-20 percent concentration, according to the peeling characteristics of the vegetables being handled. Maintenance costs are low, as there are few moving parts in the machine. The system is capable of a wide variation in peeling technique to suit any particular type of raw vegetable. Some processors use the thermal shock method of high concentration and temperature, with short immersion time, whereas others prefer a lower concentration of lye and longer dwell time. In some cases, wetting agents are used in the lye tank, to cut down the usage of 45
sodium hydroxide, or to make more effective use of the standard oncentration being used. Another technique to economise on lye is to allow the vegetables to pass from the peeler through a 'retaining reel, which is really a reel or rod washer with the water spray equipment remo dwell time in this reel, which can be 10-15min, according to its capacity, has the effect of extending the penetration effect of the lye on the skin of the regetable, thereby reducing the duty, and consequently the concentration of the lye in the peeler itself. From this reel, the vegetables pass normally to the washing process, which is either carried out in a second reel washer or in a rotating brush washer. On the debit side, the cost of sodium hydroxide is high, particularly when high concentrations have to be sustained. Also a considerable volume of water has to be used in subsequent washing, to arrest caustic burn and excessive penetration of the flesh and to remove all surface traces of lye. Again, some further chemical treatment may be necessary if peele potatoes or other vegetables have to be held in a surge hopper for any length f time prior to further processing. In these circumstances, it is usual to dose the surge hopper with 0.5 percent citric acid to neutralise any trace of alkalinity left by the lye treatment, and this, of course, adds to the cost of the operation Where lye peeling is undertaken, very special precautions must be taken to protect operating personnel against injury by contact with lye, and it is essential that the staff engaged in this department are supplied with heavy rubber boots, gloves and outer protective clothing, and goggles must worn at all times. Suitable warning notices relevant to the hazards must be displayed adjacent to the peeler, and first aid equipment to deal with caustic burns should always be close at ha Very rigid control of conditions of immersion time, temperature and concentration must be exercised, otherwise heavy leaching losses will occur, which will seriously affect the ratio and yield of end product. Leaching is the loss, by extraction, of soluble solids in vegetables, which is caused by over- immersion in either the lye peeling liquor or the blanching liquor. High temperatures are also a contributory factor to leaching in some cases (2)Flash Steam Peeling This method is extremely efficient, and has the advantage of creating fewer effluent disposal problems than other methods. The system utilising high pressure steam at 17atm ensures that even awkwardly shaped products are evenly peeled Steam at the pressure indicated heats the moisture under the skin of the vegetable in such a manner that, when pressure is reduced this moisture
sodium hydroxide, or to make more effective use of the standard concentration being used. Another technique to economise on lye is to allow the vegetables to pass from the peeler through a ‘retaining’ reel, which is really a reel or rod washer with the water spray equipment removed. The dwell time in this reel, which can be 10 - 15min, according to its capacity, has the effect of extending the penetration effect of the lye on the skin of the vegetable, thereby reducing the duty, and consequently the concentration of the lye in the peeler itself. From this reel, the vegetables pass normally to the washing process, which is either carried out in a second reel washer or in a rotating brush washer. On the debit side, the cost of sodium hydroxide is high, particularly when high concentrations have to be sustained. Also a considerable volume of water has to be used in subsequent washing, to amst caustic bum and excessive penetration of the flesh and to remove all surface traces of lye. Again, some further chemical treatment may be necessary if peeled potatoes or other vegetables have to be held in a surge hopper for any length of time prior to further processing. In these circumstances, it is usual to dose the surge hopper with 0.5 percent citric acid to neutralise any trace of alkalinity left by the lye treatment, and this, of course, adds to the cost of the operation. Where lye peeling is undertaken, very special precautions must be taken to protect operating personnel against injury by contact with lye, and it is essential that the staff engaged in this department are supplied with heavy rubber boots, gloves and outer protective clothing, and goggles must be worn at all times. Suitable warning notices relevant to the hazards must be displayed adjacent to the peeler, and first aid equipment to deal with caustic bums should always be close at hand. Very rigid control of conditions of immersion time, temperature and concentration must be exercised, otherwise heavy leaching losses will occur, which will seriously affect the ratio and yield of end product. Leaching is the loss, by extraction, of soluble solids in vegetables, which is caused by overimmersion in either the lye peeling liquor or the blanching liquor. High temperatures are also a contributory factor to leaching in some cases. (2) Flash Steam Peeling This method is extremely efficient, and has the advantage of creating fewer effluent disposal problems than other methods. The system utilising high pressure steam at 17atm ensures that even awkwardly shaped products are evenly peeled. Steam at the pressure indicated heats the moisture under the skin of the vegetable in such a manner that, when pressure is reduced this moisture 46
Table 3. 1 Relative peeling efficiency corundum Lye Peeling Peeling 3088ss 40509Los FLASH STEAM PEELING SYSTEMS TYPE 1002003004005508009501250 Pressure Vessel Volume litres 1002003004005508009501250 Door diameter. mm 200300300350350400400450 Support bearings, mm 75100100125125125 Steam connection. mm 100100125125125 Air connection. BSP.T Door seal Silicone rubber &mm dia. section Speed 6 rev. per min. Product per charge, Kg 3467100134200226333666 Steam Nominal consumptionkg/hr 100 200 300 400 600 800 1000 2000 Exhaust valve. mm 32 000 Electric 415V, 50hz, 3 phase(power), 110V, 50hz Single phase(control) Power Pressure vessel. Kw 1.51.51.51 3 Feed Conveyor, Kw 22222.222223 Discharge conveyor, Kw 222222222222223 Performance Typical example, Kg per hr1000200030004006000800010.00020.000 All capacities based on 30 cycles per hour
Table 3.1 Relative peeling efficiency FLASH STEAM PEELING SYSTEMS TYPE 100 200 300 400 550 800 950 1250 Pressure Vessel Volume, litres 100 200 300 400 550 800 950 1250 Door diameter, mm 200 300 300 350 350 400 400 450 Support bearings, mm 60 75 75 100 100 125 125 125 Steam connection, mm 60 75 75 100 100 125 125 125 Air connection, BSP.T. Door seal Silicone rubber, 8mm dia. section Speed 6 rev. per min. Product per charge, Kg 34 67 100 134 200 226 333 666 Steam Nominal consumptionKg/hr 100 200 300 400 600 800 1000 2000 Inlet valve, mm 25 40 40 50 50 75 75 75 Exhaust valve, mm 32 50 50 80 80 100 100 100 Electricity 25Opsi max WP (17 bar) Air, psi 80 80 80 80 80 80 80 80 415V, 50hz, 3 phase (power), 110V, 50hz Single phase (control) Power Pressure vessel, KW 1.5 1.5 1.5 1.5 3 3 3 4 Feed Conveyor, KW 2.2 2.2 2.2 2.2 2.2 3 3 3 Discharge conveyor, KW 2.2 2.2 2.2 2.2 2.2 2.2 2.2 3 Performance Typical example, Kg per hr 1000 2000 3000 4000 6000 8000 10,000 20,000 Ware potatoes All capacities based on 30 cycles per hour 47