145 GDS Helpsheet - EL, STD & ADV Controllers o-ring sizes and replacement
Hardware
ELDPC , STDDPC and ADVDPC
ELDPC, STDDPC & ADVDPC Controllers - o-ring sizes and replacement
This helpsheet is designed to help you find the correct size o-ring for your controllers and to guide you on how to correctly fit them.
All Controllers – O-ring size table - Mechanical resistance of the o-rings
(GDS part numbers included in brackets)
CONTROLLER | PISTON O-RING | END CAP O-RING | TRANSDUCER O-RING |
ELDPC | 38.0 x 3.0 Viton 70 (FS00330) | 47.6 x 2.4 Nitrile 70 (FS00332) | 12.42 x 1.78 Nitrile 70 (FS00660) |
STDDPCv1 | 31.5 x 3.0 Viton 70 (FS00476) | 41.6 x 2.4 Nitrile 70 (FS00853) | 11.6 x 2.4 Nitrile 70 (FS00439) |
STDDPCv2 | 31.5 x 3.0 Viton 70 (FS00476) | 47.6 x 2.4 Nitrile 70 (FS00332) | 11.6 x 2.4 Nitrile 70 (FS00439) |
200cc v3 ADVDPC | 31.5 x 3.0 Viton 70 (FS00476) | 39.5 x 3.0 Viton 70 (FS00488) | 9.25 x 1.78 Nitrile 70 (FS00079) |
1000cc v3 ADVDPC | 74.5 x 3.0 Viton 70 (FS00481) | 84.5 x 3.0 Viton 70 (FS00480) | 9.25 x 1.78 Nitrile 70 (FS00079) |
200cc v4 ADVDPC | 31.5 x 3.0 Viton 70 (FS00476) | 41.6 x 2.4 Nitrile 70 (FS00853) | ¼” BSP Dowty Seal (HY00101) |
1000cc v4 ADVDPC | 74.5 x 3.0 Viton (FS00481) | 89.5 x 3.0 Viton FS00395 | ¼” BSP Dowty Seal (HY00101) |
32MPa ADVDPC | SPECIAL | N/A | ¼” Dowty |
64 MPa ADVDPC | SPECIAL | N/A | SPECIAL |
DYNAMIC SIG 3 CONTROLLER | 31.6 x 2.4 Silicone & 31.6 x 2.4 backing ring (FS00823) | 39.5 x 30 Nitrile 70 | N/A |
ELDPC
STDDPCv1
STDDPCv2
200cc ADVDPC
1000cc ADVDPC
Fitting instructions for ELDPC and STDDPCv2
Please note - the method for replacing the o-rings on STDDPCv1, ADVDPC 200cc and 1000cc is very similar to the one below. The main differences are summarised following on from the main instructions.
On the controller keypad, FAST EMPTY to remove any fluid in the controller.
Once emptied, FAST FILL the controller to its maximum limit with just air, this will make disassembly easier. Power off and remove the power supply, CAN cables and keypad.
Turn the controller upside down to access the bottom and remove the panel. Then disconnect the transducer from the PCB
Remove the transducer (block) by undoing the M6 nuts, be ready with paper towels as remaining fluid in the cylinder may leak out when the controller is turned back over remove the nuts underneath the transducer block then turn the controller back up the right way.
Remove the two M3 cap head screws holding the bellows in place.
Using a small punch and small hammer, punch out the connecting pin between the motor and the ball screw.
Using the palm of your hand or a soft mallet, separate the motor from the ball screw. Remove the bellows and motor from the track. Carefully turn the controller back over again
Finally removing the remaining two cap-head screws underneath will allow you to fully separate the ball screw cylinder assembly from the base of the controller.
Remove the tie rods from the cylinder assembly and then remove the end cap.
Sometimes it is not easy to remove the piston from the cylinder, you can use two wooden blocks placed between the cylinder and the base of the tie rods. These blocks will work as extra support for the force to be applied to free the piston. Once the blocks have been placed in position, the ball screw has to be screwed out so the blocks can push the cylinder away.
Remove the piston, transducer block and end cap o-rings and discard if clearly damaged or deformed. Fully clean all the components of the cylinder assembly before continuing. If possible, use Scotch-Brite or fine grade emery cloth to clean the inside of the cylinder faces and piston. A fine honing tool can be used to clean the inside of the cylinder.
Please be very careful not to allow the ballscrew housing to travel to the end of the ballscrew, this will result in ball bearings coming free from the housing and the ballscrew will need replacing.
Reassembly
With the piston, internal of the cylinder and the end cap all clean and free from debris, refer to the table at the start of this helpsheet for the correct o-ring sizes required. Start by smearing the piston o-ring with some silicone grease and fitting it to the piston. Then smear some more grease around the chamfer on the end of the cylinder (make sure it is the chamfer end of the cylinder and not the other end).
Carefully slide the piston/ballscrew assembly back into the cylinder via the chamfered end, do it in circular motions whilst pushing in and be sure not to pinch the o-ring.
Take the end cap o-ring and grease it with silicone grease, place the in the end cap o-ring groove, carefully fix to the cylinder using the tie-rods, only do the nuts up finger tight at this point.
turning the controller the right way up, place the cylinder assembly in position, using this position, tighten up the tie-rod nuts uniformly ensuring the flat surfaces on both of the ends of the cylinder assembly are square and flush against the body of the controller.
Screw in finger tight the caphead screws and nuts holding the cylinder assembly to the base of the controller. Slide the bellows over the ballscrew, carefully slide the motor back onto the rail.
Using a small hammer, refit the pin in the hole attaching the motor to the ballscrew.
Now the motor and ballscrew are aligned, you can tighten up the caphead screws and the M6 nuts securing the cylinder to the base.
Take the transducer o-ring and apply grease to it then place in the o-ring groove from underneath. Attach the transducer block with the other two M6 nuts.
Reattach the cables and any cable clips in the controller, then screw the base of the controller back on.
Finally, refit the bellows keeper ring to the motor and then reattach the CAN cables, keypad and power on the controller. Fast empty the controller and then fast fill to check alignment and that everything works OK. Fill with water and pressure test.
Key differences in changing the o-rings on STDDPCv1, ADVDPC 200cc and 1000cc
The general guidance on changing the o-rings in these controllers is the same as above with some obvious exceptions.
These controllers don’t even need to be tipped over, simply remover the top plate, fully disconnect any wires (transducer, earthing, etc) and then lay the top plate upside down to give you access to the screws holding the cylinder assembly in place,
The way in which the cylinder comes apart is slightly different, there are no tie rods, just cap headed screws on either end of the barrel.