Model 640 & 640CC Instruction Manual
D01206676
Revision A February 2016
31
12
Maintenance and Servicing
Consistometers can be relatively reliable and trouble free - provided they are
serviced and maintained properly. Instruments that are neglected and receive
infrequent service or are subject to abuse are certain to cause trouble.
Pressure Valve and Hydraulic System Maintenance
12.1
The metal o-ring, the pressure vessel o-ring seat, and the bottom of the seal shaft
are the keys to reliable pressure sealing. If these components are free from debris
and scratches/dents, reliable sealing will be easily achieved.
1.
Inspect the pressure vessel’s metal o-ring and the seat below it after each test
and wipe it free of cement particles and other debris. Do not use sharp objects,
such as screwdrivers, when removing the metal o-ring as it will likely bend or
scratch the o-ring, ruining it. Should the seat below the o-ring or the seal shaft
become pitted or scratched from cement particles that have migrated into the
seal, lapping of the seat and seal shaft may be required.
2.
The cylinder plug threads have been coated with a friction reducing PTFE
coating by the factory to help prevent thread seizing and galling. However, it
is still recommended to apply a molybdenum disulfide anti-seize compound to
the threads periodically.
.
If the transfer of the oil from the pressure vessel to the reservoir
is slow, the filter needs to be cleaned or replaced
3.
The high-pressure filter is located in the 3/8-inch stainless steel pressure lines,
between the pressure vessel and the pressure release valve. This filter protects
the pressure release valve, air operated valve (if equipped), and capillary tube
(if equipped) from cement particle damage and/or blockage. It also prevents
cement particles from being carried into the oil reservoir. This filter must be
disassembled and the filter element cleaned or replaced periodically.
4.
The mineral oil in the reservoir should be drained and replaced when it
becomes dirty. The low-pressure oil filter element should also be replaced
periodically. These filters are located in a blue housing. The oil reservoir is
equipped with drain valve on the bottom and a filling plug at the top. To
thoroughly clean the reservoir, the entire unit may be taken out of the
instrument and the bottom removed. Mineral oil may be conveniently added
by pouring oil into the pressure cylinder and transferring it to the oil reservoir.
