Mobile Mixing Units for
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Concrete
MO fewer than 24 A.E.0 Monarch N.Vehicles • will soon be associated with an enterprise which, representing a comparatively new industry is already effecting • widespread changes in established building procedure. The rubling of concrete on the building sites, with its many drawbacks, is being superseded by lorry-mixed concrete which, as is indicated by the term, is concrete prepared at a central batching plant and delivered by motor vehicles ready for use.
The two principal advantages of this system are that the engineer or contractor can rely upon the availability of concrete mixed with absolute accuracy and delivered in uniform strength and density, and that the contractor can dispense with his mixing plant.
A recent entrant into this field of enterprise is Express Supply Concrete, Ltd., which has its central hatching plant at Paddington, London, W.2. The company makes extensive use of A.EC. units for delivery pur
poses. Minute care is exercised at this central hatching plant to ensure that the constituents — aggregates, sand, cement and water—are measured exactly to the engineer's or architect's Specification.
The road vehicles into which the raw materials are precipitated are mobile mixing units. Each consists primarily of a cir
cular container. mounted so that it can be freely revolved by a small 14 h.p, petrol engine mounted at the front of the chassis. A manhole at the top of the container is
used for filling, and an axial opening at the rear enables the contents to be discharged via two adjustable chutes. The tank holding the mixing water has its outflow controlled by dual levers, the first in the driver's cab, the second on the rear platform.
To facilitate easy manceuvring in confined spaces the A.E.C. Monarch petrol-engined chassis have short wheelbases of 12 ft. 1 in. and specially shortened frames. They are also equipped with fully Boating doublereduction bevel rear axles.
According to the urgency with which it is required, the concrete is either finally mixed during the journey or at the point of arrival, where its discharge is effected by the action of the mixing panels within the container pushing it against the rear opening, which is controlled by a large handwheel.
As the name of the operator implies, rapidity of delivery is a leading characteristic of the system. The actual loading at the hatching plant takes no more than a mins. ; the dischargeof 24 cubic yds of concrete takes less than 5 mins This means that a normal order can be fulfilled within half an hour of its receipt. With the fleet. of A.E.C.s operated by the company, deliveries can be Continued at short regular intervals for so long as the concreto can be accepted.