Mark 3 Bulkflo and Corvette in production
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• Dunnspencer Bulkflo Ltd., of Ilion, near Ilminster, Somerset, has announced that the latest versions of the Bulkflo Mk. 3 and Corvette full-width vibrating-hopper type pneumatic-discharge systems are now in full production, and are being fitted as standard equipment to the company's bulk animal feed tipping vehicles. Exhibited at the 1968 Earls Court Show in prototype form, the equipment is produced by an associated company, Spencer (Melksham) Ltd., of Melksham, Wilts., mechanical handling specialists. The two systems are basically similar, the Corvette being the "utility" version.
Located above the rotary seal, the vibrating hopper is mounted in a special type of nylon-reinforced rubber developed for the application and is vibrated by a single hydraulic motor through the medium of an eccentric mechanism. Because the hopper extends the entire width of the body the tendency of sticky materials to bridge the trunk feeding the rotary seal is reduced and this is a particularly favourable factor in the case of light bulky materials such as meals and mashes. The effective sealing provided by the hopper's rubber mounting, and connection with the rotary seal by a flexible bellows, eliminates "leakage" of material. Furthermore, the body is completely selfemptying, obviating the necessity for manual clearance of residue material, while employment of a full-width hopper allows the construction of the system to be simplified.
The rotary seal is also driven by an axial-type hydraulic motor, all the hydraulic equipment being of Edbro manufacture. Hydraulic power is derived from an Edbro combined pump and p.t.o., compressed air being supplied by a Roots blower driven from a p.t.o. through a I-to-2 step-up gear. The possibility of blow-back is, it is claimed, eliminated by machining the cast-steel rotor and casing "as a pair" which enables the two components to be assembled with fine tolerances. Having angled blades, the rotor Ls designed to minimize degradation and >eparation of materials and to give a ontinuous feed.
Operational flexibility is obtained by ;eparate control of rotor and vibrator ;peeds (by means of hydraulic return /alves) and provision for running the rotor Ind vibrator separately. Push-pull control ;fides are used to control the amount of naterial being tipped into the throat of the 'otary valve to match the weight of the naterial to the air supply, which is necesary to prevent blockage. The iormal operating pressure of the system
is 1,100 p.s.i., a safety valve being fitted that operates at 1,500 p.s.i and thus reduces the likelihood of extensive damage in the event of a foreign body finding its way into the system.
Pellets that can be handled by the system include large sow nuts of up to l+in. by A flow control valve is used to balance the amount of oil required for the operation of the tipping gear with the amount required by the hydraulic motors if all the equipment is in operation at the same time.
Current orders for the system include one for four vehicles that will be operated in Eire by millers in the area. Light-alloy bodies of Dunnspencer design are being built by Griffiths J. Roberts Ltd., of Dublin, for the vehicles and the equipment is being supplied in CKD form.
Nearer to home, a Seddon 22-ton-gross articulated outfit, equipped with a Corvette system has recently been supplied to H. F. Heard Ltd., of Cullompton, Devon, which operates some eight Bulkflo bulk poultryfeed vehicles. Bulk vehicles fitted with the original type of Bulkflo vibrating hopper system have been supplied to Czechoslovakia, East Germany, Spain and Russia during the past two years.