1008

THE COLLIERY GUARDIAN.

May g 1.914

THE “JUMPER” CONTROL GEAR.

For Electrically Driven Pumps and Compressors.

We have recently had our attention drawn to a
new type of automatic controller for unloading,
starting, and stopping electrically driven pumps
and compressors, invented by Mr. Towler, of the
Leeds Engineering and Hydraulic Company
Limited, Rodley, near Leeds.

case there is less current to deal with; furthermore,
the motion imparted to the controller should be
slow when on the contacts, and relatively quick
when passing from contact to contact.

A patent has been recently granted to Mr. Alfred
Towler for an automatic control gear embodying
the foregoing principles which are herewith
described. The “ Jumper ” control gear is shown
in the accompanying drawings, of which fig. 1
represents the general arrangement of the entire

tinel valve which closes and keeps closed the by-
pass valve which loads the pump; in like manner
when the accumulator has reached its highest posi-
tion and tipped over the pilot valve the main gear
moves it to the “ off ” position; in doing this it
first unloads the pump by opening the by-pass
valve.

The “ Jumper ” gear can be made to actuate any
type of electric controller, but the controller which
we believe is generally preferred by users is the

I

Fig. 3.—Pilot Valve and
Striking Gear.

Li ■

fa

Fig. 5.—Enlarged Section of By-Pass Valve.

G.

I

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Fig. 1.—Arrangement of Controller as Applied to an Hydraulic Accumulator.

Fig. 4.—“ Jumper ” Control Gear.





Fig. 2.—Plan and Section of Control Gear.

Starting and stopping hydraulic pumps auto-
matically is usually done by the accumulator actu-
ating a trip switch or pilot valve by tappet gear,
and in the case of air compressors by the variation
in pressure in the receiver. From a mechanical
point of view this should be done gradually, and
from an electrical point of view with, as little
sparking and excess of current as possible. As
electric motors, and particularly those of the A.C.
type, start up and stop much too quickly for ideal
pumping conditions, the pumps should preferably
be unloaded prior to these operations, in which

apparatus, with sectional detail of pilot and by-
pass valve. Fig. 2 shows a section of the gear
proper which consists of a hydraulic cylinder. A
actuated by a pilot valve B and accumulator strik-
ing gear C C (shown on fig. 1), a cataract D, a
sentinel valve E for actuating the unloading valve
F (shown on fig. 1), the speed of the unloading
valve being governed by the needle valve G, a rack
and pinion and gearing or pitch chain being
employed for connecting the gear to the electric
controller H. When the gear is in full “ on ”
position, and not until then, it actuates the sen-

drum or tramway type, because in this type the
contacts are usually large, easily get-at-able, and
cheaply renewed.

In order to reduce the wear and tear of the con-
tacts it is desirable to impart a “ jumping action ”
to the controller drum, hence its name. This is
effected by inserting a rod M inside the cataract D
on which there are a series of alternately raised
and recessed parts corresponding with the number
of contacts in the controller. The raised parts fit
the hole in the cataract piston N. When the piston
comes to a raised part it passes slowly over it, and