MTS Series 111 Accumulator - Manual (Page 35)

Non-MTS accumulators typically use either a poppet–type valve or a core–type valve.
1. Determine which type of gas pressure valve is present on the accumulator and connect the charging kit
chuck valve to the accumulator valve stem.
2. Open the locknut (poppet-type) or chuck valve (core-type).
Note:
The poppet-type valve opens by turning the locknut counterclockwise and closes by turning the
locknut clockwise. To open a core–type valve, attach a chuck valve to the valve stem and turn the
chuck valve handle clockwise to depress the valve core. Close the valve by turning the handle
counterclockwise.
3. Read the pressure on either the high or low accumulator charging kit pressure gage.
The low pressure gage is limited to approximately 1.4 MPa (200 psi) by the gage protector.
• If the pressure reading is other than the required pressure level recorded on the accumulator, go to
the procedure “Change the Precharge Pressure.”
• If the pressure level corresponds to the level recorded on the accumulator label, close the locknut
(poppet-type) or close the chuck valve (core-type). Continue to Step 4.
4. Open the bleed valve on the accumulator charging kit and remove the chuck valve from the accumulator.
5. Replace the valve stem cap and protective cover on the accumulator.
6.3.0 About Changing the Precharge Pressure
The precharge of an accumulator mounted on a hydraulic supply line often is increased to enhance system
performance and reduce the transient HPS flow demands. Accumulators may be precharged to 10 MPa (1500
psi) or more, although amounts above 14 MPa (2200 psi) will have less and less performance effect in most
situations. Be sure that you read the following warning before you charge your accumulator.
Warning:
Accumulators have specific pressure ratings.
If the precharge pressure is too high, the accumulator can bottom out causing the release
of metal particles into the hydraulic fluid. Charging accumulators above their rated level
can damage system equipment.
Do not charge accumulators to pressures above their rated level. Charge accumulators below
their rated fatigue pressure of 21 MPa (3000 psi) for the Model 111.11B and 22 MPa (3200 psi)
for the Model 111.12C. Use a suitable regulator and gage set to an accumulator’s charges.
6.3.1.0 Decrease the Precharge Pressure
See “Check the Accumulator Precharge” to determine if you need to change the precharge pressure.
Series 111 Accumulator Product Information 35
6.0 Maintenance