MTS Model 506-62-72 Hydraulic Power Supply - Manual (Page 19)

Service 3-7
3 . 1 . 3 Accumulators
For more information
about accumulators See the Series 111 Accumulator product manual(MTS part number
115533-XX). For other accumulators, refer to the vendor literature or
the Procedure for Checking Piston and Bladder Type Accumulator
Precharge and Precharging (MTS part number 408266-XX).
3 . 1 . 3 . 1 Precharge Pressure-Checking Intervals
Precharge pressure of the pressure accumulator must be checked at
regular intervals. To establish an interval time, follow this procedure:
HPS – Side View
VW-G044J
DIRT ALARM
slow turn-on
accumulator
pressure
accumulator
CHANGE OK
1. Initially, check the precharge pressure after 2 weeks or 100
operating hours
.
2. If the pressure changes more than 200 psi, check the precharge
pressure every week or 50 operating hours.
If the pressure changes less than 200 psi, check the precharge
pressure every four weeks or 200 operating hours.
Precharge pressure of the slow turn-on accumulator must be checked at
regular intervals. To establish an interval time, follow this procedure:
1. Initially, check the precharge pressure after 2 weeks or 100
operating hours
.
2. If there is a pressure-level change of more than 50%, check the
precharge pressure every week or 50 operating hours.
If there is a pressure-level change of less than 50%, check the
precharge pressure every four weeks or 200 operating hours.
3 . 1 . 3 . 2 Precharging the Accumulators
If the pressure accumulator has a pressure-level change of
±
200 psi
between checks, recharge it. If the slow turn-on accumulator has a
pressure-level change of
±
50% between checks, recharge it.
The pressure and slow turn-on accumulators are typically precharged to
1000 psi (7 MPa) and 800 psi (5.5 MPa), respectively. These are the
recommended levels for an HPS output pressure of 3000 psi (21 MPa).
3 . 1 . 3 . 3 Changing the Accumulator Seals
When you have established a regular interval for checking the
precharge pressure, note the amount of pressure loss that occurs each
time the precharge pressure is checked. If an increase in pressure loss
occurs during the period between checks, the seals may require
replacement.