WIKA CPP1200-X - Handbuch (Seite 19)

19 WIKA operating instructions model CPP1200-X
GB
14076968.01 12/2013 GB/D
4. Design and function
4.3.1 Spindle pump
The spindle pump is bolted to the reservoir/high pressure cylinder block fastened to the
base unit. A sectioned view of the pump is shown. The rotating handwheel (C) which
is operated by the spokes (D) is attached to a threaded spindle (E). The spindle is
supported in a sintered bearing (F). As the spindle (E) is rotated, it drives a non-rotating
ram (E and K) forward, the thrust being taken by a needle thrust bearing (G). The large
diameter of the ram (H) in the barrel of the pump (J) primes the pressure system and
provides the low pressure up to approximately 140 bar (2,000 lb/in²). The small diameter
of the ram (K) in the reservoir/ high pressure cylinder block provides the higher test
pressures up to 1,200 bar (16,000 lb/in²).
4.3.2 Reservoir
A liquid reservoir is provided on the top of reservoir/high pressure cylinder block. The
reservoir is provided with a translucent cover to enable the reservoir level to be monitored.
A plug in the middle of the reservoir cover enables the reservoir to be filled or topped up
(the plug is removed whilst the test pump is in use). The reservoir contains enough liquid
(approximately 150 cm³) to enable normal operation of the test pump to be carried out.
Low pressure ram displacement = 60 cm³
High pressure ram displacement = 10 cm³
4.3.3 Control valves
Two control valves are provided on the top of reservoir/high pressure cylinder block.
The valve mechanisms are built into the reservoir/high pressure cylinder block and they
control the flow of liquid through internal drillings in the reservoir/high pressure cylinder
block. The rear valve is referred to as valve A and is used to control the output from the
high-pressure ram of the spindle pump. The front valve is referred to as valve B and is
used to control the flow of liquid to and from the reservoir.
4.3.4 Connection blocks
Pressure supply pipes from the spindle pump are terminated at two pressure blocks
mounted on the base unit. The pressure blocks are fitted with threaded bosses
projecting up through the cover plate of the base unit. These threaded bosses enable
the delivered test connections to be directly screwed on to them, and it is also possible,
using threaded adapters, to connect the various sizes of measuring instrument
connections. Oil cups are fitted to the unit cover around the threaded bosses of the
connection blocks to catch any oil drips from the gauge stand during gauge fitting and
removal.