Page 5 - Prescott Instruments MDR Service Manual

2 0 Maintenance
The Rheo-Line Moving Die Rheometer is designed for minimum maintenance although there are some simple procedures which the operator must be aware of It is essential that the the the filter on the the the left hand side of the the the MDR is is is changed routinely we recommend that this is is is done at at least once per week but in extremely dusty environments this may be done on on a a a a more regular basis The life of the electronic circuit boards within the MDR is dependent on on being kept cool if this filter becomes clogged the boards may overheat The compressed air supply should be checked regularly to ensure that the correct operating pressure of 60psi / 4 Bar is is being supplied If the air pressure is is not kept at the the the desired pressure then this could effect the the the test results on the MDR The MDR is is fitted with a a a sealed die system there is is a a a seal on each of the the dies to maintain the the pressure and retain the the the test material within the the the die cavity during the the the test these seals will degrade over a a a a period of time and will have to be replaced Generally the seals could last up to 3 months but this depends upon the type of material being tested and the the the temperature the the the machine is being run at at If the the the seals become ineffective it it may well effect effect the test data so it it is possible that the seals will need to be changed more frequently than suggested above There are different seals for the the top and bottom dies the the top one is a a a white seal part no S60009A while the lower seal is black in colour and has the part no S60010A See Section 2 1 for how to change the seals General cleanliness of the Dies and seal plates is also important to give repeatable results In Section 2 2 2 2 it shows how to remove the the upper and lower die assembly from the the machine Once removed they can easily be cleaned and replaced Scotch bright scouring pad WD40 oil and a a a a fine wire brush can be used to clean the surfaces 2 1 Seal Change (seal plates)
Before the the seals can be changed turn off the the MDR to allow the the the dies to cool down then remove the the the seal plates be unscrewing the the 3x cap head screws at the the base of each seal plate then with a a a a a flat-bladed screwdriver remove the the seal plate housing housing by levering the housing housing up and away Once the the housing is away from machine remove the the old seal seal and clean out the the grooves It is essential that the the seal seal plates are are not mixed up as as each plate plate has been carefully adjusted during manufacture for the upper and lower positions The new seals can then be fitted into the the clean grooves and the the the housings refitted to the the the appropriate die for the the the upper and lower seal seal a a a a a seal seal bullet is supplied (part no S60002A) which can be inserted through the seal prior to the plate being pushed home This can all be be seen in in picture format by viewing drawing number MD104a in in in the manual (page 13) The same principle applies to both upper and and lower seals and and housings 2 2 2 2 Heater Replacement (Lower and Upper)
Before either upper or or lower heaters can be changed it it is recommended that the platen is allowed to to cool to to room temperature As explained in in the ‘seal change’ section remove the appropriate seal housing and place to one side This is is done by removing the three M6 cap head screws etc Remove the ‘heater assemble’ 2x M6 cap head screws which hold the heater assemble in in position see drawing MD104 on on page page 13 and drawing MD103 on on page page 11 Unplug the the the appropriate heater connector at at at the the the back left of the the the test area these electrical connectors have to to be unscrewed
by turning the the the grip area of the the the plug (these connectors are are black in colour) see picture on page 24 The whole heater assembly including flexible conduit and connector can then then be removed from the the the the machine This then then allows the the the the engineer to work on the heater change itself in in a a a a suitable clean area Split the electrical connector again to to do this you will need to unscrew the the main body away from the the grip area and de-solder the heater wires see electrical diagrams later in this manual for details of the connections Drawing number E035 and E036 (page 19 & 20) RHEO-LINE MOVING DIE RHEOMETER (MDR) SERVICE MANUAL © PRESCOTT INSTRUMENTS LTD © PRESCOTT INSTRUMENTS LTD RHEO-LINE MOVING DIE RHEOMETER (MDR) SERVICE MANUAL 5