US2068779A - Cooling roll refiner or like mill - Google Patents

Description

A. A. TUNLEY ET AL Filed Oct. 25, 1934 INVENTORS ALLAN ASH/MEAD TU/VL E Y l I F l L COOLING ROLL REFINER OR LIKE MILL Jan. 26, 1937.

GEORGE RALPH BAKER BY M I 7 'Azf nusv Patented Jan. 26, 1937 UNITED STATES COOLING ROLL REFINER R LIKE MILL Allan Ashmead Tunley and George Ralph Baker, Peterborough, England, assignore to Baker Perkins Co. Inc., Saginaw, Mich.

Application October 25, 1934, Serial No. 749,905

. In Great Britain October 25, 1933 2 Claims.

This invention relates to the cooling of rolls or dissipation of the heat evolved in the operation of refiner mills-such as, for example, chocolate fiveroll refiners, or to the cooling of rolls of a similar character where heat is generated by the grinding operation and where the nip between the rolls is of a fine order such that the defect due to heating becomes cumulative. The invention will, however, be described for the sake of simplicity with 0 reference to chocolate roll refiner mills.

The object of the present invention is to provide an improved means for internally cooling or abstracting the heat from rolls or refiners in a markedly increased degree as compared with 5 present day cooling systems or means, an aim of the invention being to carry away from the metal of the roll a considerably higher percentage of heat than has hitherto been possible.

It has been observed that the circulation of water through refiner rolls fails to secure a cooling to the extent to be expected and it is thought that this lack in efiiciency is due to the inner peripheral surface of the roll becoming coated with an insulating film or a layer of stagnant 5 water.

The invention broadly consists in providing cooling water currents in contact with or directed against the internal periphery of a roll such that the water has a scouring action upon the insuo lating film.

The invention is directed to the production of currents of a velocity, direction, or turbulent effect adapted to disturb this insulating film or stagnant layer of water so that the cooling water 5 has free play to carry off a considerable portion of the heat units evolved either over the entire internal surface or at a sufficient number of distributed spots or localities in view of the high conductivity of the mass of metal of the rolls, such that the roll surfaces are kept at a tem perature below that at which defects due to their expansion can arise.

A feature of the invention lies in the provision of partitions or baiiiing means which direct the circulated cooling water against the internal wall or portions of the wall of the roll.

In the accompanying drawing,

Figure 1 is a longitudinal section of a roll having current producing means according to the invention.

Figure 2 is a cross section.

Figure 3 diagrammatically illustrates a fiveroll refiner with a water circulating system.

In carrying the invention into effect according i to one convenient mode as described with reference to a single roll, by way of example, one of the trunnions 5 of the refiner roll 6 is hollow and formed integral with a roll end closing head I, the hollow trunnion serving for the accommodation of inlet and discharge conduits for cooling 5 water or serving as the return or discharge conduit. A series of partitions 8 adapted to lie in planes at right angles to' the axis of the roll are mounted in a frame constituted by bars or rods spaced from a central inlet pipe 9 and parallel 1 thereto. The partitions 8 may be apertured to receive the rods or bars and may be welded thereto; alternatively, the rods or bars may comprise a bolt member ill on which the sleeves II are threaded to act as spacing members between the 5 partitions and by means of which the bolt is employed to clamp the partitions in position. The partitions are provided with central apertures I 2, and are threaded over bosses l3 on the inlet pipe 9, packing sleeves l4 being provided whereby the pipe is supported in position.

The partitions 8 are of disc form and are of a diameter slightly less than that of the internal diameter of the roll so that the frame may be slid into position within the roll while the discs snugly fit against the internal surface thereof.

The partition 80., nearest the end of the roll, may be of slightly larger diameter than the internal diameter of the roll and may be clamped between the roll end head I and an internal rabbet or shoulder [5 formed on the roll end, or the partition frame may be otherwise secured to the roll so that it rotates therewith. The partition at the other end of the frame may be similarly secured.

. Each partition disc I has a plurality of segmental slots I 6 at its periphery which may be formed by the removal of a segmental piece of metal from the periphery, the idea being to provide shallow elongated passageways which constrain the cooling water to flow at a substantial velocity through the slots and in close contact with the inner surface of the roll. Instead of providing slots in the periphery, elongated apertures may be formed in the discs adjacent the 5 periphery in which case it is preferred to press or stamp the apertures out of the metal of the discs leaving a tongue lying obliquely so as to direct the circulating water as it fiows therethrough to impinge upon the roll surface.

The end disc 8a is provided with a circumferential series of apertures l'l, forming outlets for the flow of water to the interior of the hollow trunnion 5. The cooling water is supplied through the central pipe 9 and is led to the end of the roll farthest from the supply inlet. It is also emitted from the pipe at the intermediate perfo rations ll in each of the chambers defined by the partitions 8 and 8a. The outflow may be according to known circulating systems through the hollow trunnion 5, or through a pipe surrounding the central pipe 9, and located in the hollow trunnion so that discharge commences as soon as the water in the nearest partitioned chamber rises to the half -way level.

The circulation to the various rolls in the refiner may be effected in parallel by connecting the inlet pipes 9 (see Figure 3), to a common supply pipe l9, connected to a pump 20, and driven by a motor 2|. The pump is supplied from a tank 22, to which the return flow from the various hollow trunnions is delivered by way of a duct 21, in the roll frame or casing. The tank is supplied with tempering water by a pipe 24, and is provided with an overflow 25 for water displaced from the system. The pipes 9 are provided with control valves 25 whereby the desired rate of flow for each roll may be obtained or the flow to any particular roll may be cut off.

It is preferred that the number of partitions 8 should be at least six for the ordinary roll refiners but this number may be increased where it is desired to increase the number of spots longitudinally at which the scouring action of the water is effected. Similarly, the slots or apertures at the periphery of the partition IS may be varied either as to number or circumferential extent.

According to one form where supplementary means are provided for positioning the partition frame, instead of providing peripheral slots IS in the partition discs they may be of correspondingly less diameter so that there is a continuous clearance between each partition edge and the internal surface of the roll.

The cooling system may be arranged to circulate water with an outflow at the half-way level or the circuit may be a forced closed circuit so that the interior of the roll is substantially filled with water. The system may provide for the circulation of cold water or water tempered to system of heated water on the one hand and cold water on the other. Water is circulated through the roll at a sufficient velocity to cause it to scour the internal surface of the roll and prevent any stagnant layers or pockets of water to be formed. The rate of circulation will depend upon the clearances provided. In connection with a 16" diameter roll where six partitions are provided each having six segmental slots of /2 radial measurement and 3" circumferential extent, the circulation of water at 10 to 12 gallons per minute has been found effective.

Longitudinally extending plates may be arranged between each pair of partitions and supported thereby, the outer edges of such plates lying close to the inner periphery of the roll and having a cut-out or serrated outline whereby cross currents will be set up as the roll revolves.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is:-

1. A refiner re. having cooling means comprising a series of battles secured to and rotatable with the roll, an inlet pipe extending through central apertures in the baffles and arranged and adapted to admit water between each pair of battles, said baiiies having circumferential gaps adjacent the inner periphery of the roll, spacing rods presenting a frame for supporting said baffles, an end baffle being gripped between a shoulder on the roll and a closing head of the roll.

2, A refiner roll having cooling means comprising means for maintaining a body of water within the roll, a series of transverse baflie plates having circumferential gaps therein adjacent the inner periphery of the roll, and inlet means for said roll arranged to supply circulation water to the baffled spaces between each pair of baflies.

ALLAN ASHMEAD TU'NLEY. GEORGE RALPH BAKER.

the desired degree by the passage from or into the

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