©Allspeeds Ltd
This equipment is manufactured to the highest
standards of workmanship and will give years of
satisfactory service with the minimum of attention
providing the following points are borne in mind.
The Hydrapak, is a 2-speed light-weight totally enclosed
pump in corrosion resistant alloys and suitable for use
with oil or water. All pumps are fitted with a standard
low pressure plunger which has an output of 51 cc. per
stroke and a maximum pressure of 52 bar (750 psi), but
there is a choice of six sizes of high pressure plunger
covering a pressure range of 110 to 690 bar (1600 to
10,000 psi). The actual high-pressure of which your
pump is capable (depending on the size plunger fitted) is
indicated on the end cover.
Pressure Plunger Assemblies with the following High-
pressure plunger sizes, are available.
All valves etc. are readily accessible for cleaning and
maintenance and a suction filter is fitted for protection
against the ingress of dirt, etc.
In addition to the operating handle, there are two
controls; a release valve and push/pull pressure
selection button.
The pump is fitted with a rubber faced delivery valve
and ball-type suction valves, one for high pressure and
one for low pressure. When the pump is operating on
low pressure, both high and low pressure pistons are
operative. The action of the pressure selection button is
to lift the low-pressure suction ball off its seat so that
the low- pressure system is rendered inoperative: only
the high-pressure piston is operative at this point.
Choice of the Hydraulic Medium
Oil is preferable as a medium because of its lubricating
qualities. A good quality hydraulic oil of ISO 32 viscosity
should be used.
When water is used it should be clean and soft and be
changed if impurities are picked up during operation.
Operating the Pump
First ensure that the release valve is closed by rotating
the control knob clockwise as far as it will go. Tighten by
hand only. Engage the operating lever in the most
convenient position and check that the pressure
selection button is pulled out. The pump will now
operate on low pressure. When the effort on the lever
becomes excessive (pumping against a pressure over 52
bar), the pump should be changed over to high pressure.
To do this push the pressure selection button in as far as
it will go. Do not apply effort on the operating lever
whilst performing this changeover or you will prevent
the push button from being pushed fully home. Take
care not to operate the pump when oil in the cistern is
low, as air may be drawn in and the system will have to
be vented.
To release the pressure, rotate the release valve control
knob anti-clockwise. If the system is backloaded (as
would be the case with a jack or ram and cylinder still
under load) the valve should be cracked open very
gently in order to prevent rapid return of the ram. The
valve is fully opened by approximately three and a half
turns.
The Operating Lever
The operating lever socket has a square broached hole,
situated off the centre line of the handle axis, so that by
turning it over, additional alternative positions are
available.
Seven positions of lever engagement are possible, at
intervals of 45°, with this arrangement the maximum
swing of the lever is 60°.
Charging and Venting the System
After charging the system with fluid, all air should be
expelled, via an air vent at the highest point in the
system by operating the pump on low pressure. The
Hydrapak Pump may be operated in any position except
one, i.e. on end with the front delivery connection
downwards. When in this position it is not possible to
expel all the trapped air and this will cause inefficiency.
(See later notes).
Rocker Shaft
Occasionally charge the rocker shaft bearing surfaces
with a medium grade grease via the nipple provided.
Suction Strainer
This strainer needs occasional thorough washing out in
clean paraffin to remove all the filtered dirt. Remember
to close the release valve when the suction strainer is
removed otherwise the system will empty itself through
the passageway. After cleaning and replacing the
strainer the pump should be vented.
High Pressure
Plunger diam
1/2"
9/16"
5/8"
3/4"
1"
1 1/4"
Max working bar
690
552
448
310
172
110
Pressure (psi)
10,000
8,000
6,500
4,500
2,500
1,600
Displacement per
stroke (c.c)
3.6
4.6
5.7
8.1
14.5
22.6
HYDRAPAK PUMP OPERATING INSTRUCTIONS