The Mechanical Handling and Storing of Material
Forfatter: A.-M.Inst.C E., George Frederick Zimmer
År: 1916
Forlag: Crosby Lockwood and Son
Sted: London
Sider: 752
UDK: 621.87 Zim, 621.86 Zim
Being a Treatise on the Handling and Storing of Material such as Grain, Coal, Ore, Timber, Etc., by Automatic or Semi-Automatic Machinery, together with the Various Accessories used in the Manipulation of such Plant
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720
THE MECHANICAL HANDLING OF MATERIAL
the said wheel. This confines, as has already been remarked, the error due to loss of
motion between the pawls and the wheel to one-tenth of a tooth. There is also a set
of ten retaining pawls attached to a fixed stud on the body of the machine. The large
steel ratchet wheel is keyed upon a spindle connected with the registering counter,
while the frame carrying the pawls swings freely upon the boss of the wheels. This
frame has a reciprocating motion imparted to it by means of the cam previously
described. This machine is built by Messrs Samuel Denison & Son, Ltd., Leeds.
The Merrick Weightometer.—-This continuous weighing machine consists of
weighing levers and steelyard or beam, similar in principle to those of the usual
platform scale, but of such design that a short section or portion of the working strand
of the conveyor can be suspended from the weighing levers. Fig. 1034 shows such a
machine applied to a portion of a band conveyor, whilst Fig. 1035 gives a diagrammatic
sketch of the integrator.
The weight of the load on the suspended portion of the conveyor, regardless of its
distribution, is at any instant automatically counterbalanced by the buoyancy of a
cylindrical iron float suspended from near the long end of the weighing beam, and
Fig. 1034. The Merrick Weightometer in connection with a Band Conveyor.
partially immersed in a bath of mercury. Any increase or decrease of load on the
levers will either raise or lower the float in the mercury until the loss or gain in
buoyancy compensates for the variation in load.
The function of this float is to ensure the movement of the beam from its zero
position (that is when the conveyor is empty) being proportional to the weight of
material at any instant on the suspended portion of the conveyor. The extreme end
of the beam is connected with a totalising mechanical integrator, which derives its other
factor from the travel of the conveyor by means of suitable gearing from a jockey pulley
on the return belt, or a sprocket wheel if on a chain-driven conveyor.
The integrator continuously totalises the product of two quantities, one proportional
to the weight of material suspended, and the other to the travel of this material. The
result, therefore, represents the total weight of material, and is plainly indicated by a
register in units and tenths of units of either ordinary or metric tons.
For cases where the material handled adheres to the conveyor in a varying amount,
an attachment is added which automatically counterbalances the variable weight of
the empty conveyor. This avoids frequent adjustment to 'meet the changes in the
weight of the empty conveyor and material that may adhere thereto. A magnetic
counter can be applied which will duplicate the reading of the scale register in an
office or at any other point remote from the scale itself and present the record.