An energy storage device, a hydraulic accumulator is a pressure storage reservoir in which non-compressible hydraulic fluid is held under pressure by compressed gas. An accumulator is used in a hydraulic system to meet extremes in flow demand allowing the supply circuit to respond more quickly to any temporary demand and to smooth pressure pulsations.

Test Based Sizing Tips

One Shot Test Accumulator sizing
A 1 gallon accumulator  provides 12 cubic inches of oil at a 300 psi drop with a 1500 psi pre-charge.
A 4 liter accumulator provides 210 cubic cm of oil at a 21 bar drop with 104 bar pre-charge.

Cyclic Test Accumulator Sizing
V = Accumulator Volume
A = Piston Area
D = Pk-Pk Actuator Displacement

For Gallons
V = 0.03 x A(in2) x D(in)

For Liters
V =  0.007 x A(cm2) x D(cm)

For short duration, high flow demand tests, an accumulator bank can be used in place of a large hydraulic power unit. The bank can be charged with a small displacement pump, saving energy and reducing your equipment costs.

21 and 22 Hydraulic Service Manifolds (HSM)

21 and 22 Series Hydraulic Service Manifolds can provide for multiple output pressures or isolated source connections from a single high pressure supply. With the ingenious application of accumulators, relief valves, porting valves and check valves a critically designed manifold block assures the proper hydraulic supply for varied applications. Benefits include:

  • Fluid filtration protects components downstream from impurities in the hydraulic fluid.
  • Slow ON/OFF pressure switching decreases pressure pulses and abrupt load application.
  • Electrically controllable high/low pressure.
  • Smooth pressure transitions as accumulators damp pressure fluctuations
  • Short term energy storage as accumulators supply fluid for peak flow requirements.
  • Accumulators help regulate variations in fluid supply and demand.

The 22 Series HSM provide for servo-valve mounting in addition to all of the features available on the 21 Series HSM. Setting the standard for service manifolds with advanced design, quality components, and variety of options, the 22 and 23 Series manifolds are direct replacements for MTS 293 models.

Features

  • Pressure ramping — An electrically adjustable proportional valve allows you to ramps pressure from low to high or vice versa.

  • Accumulators — Close-coupled pressure and return accumulators positioned close to the servo-valve improves the high-frequency response characteristics of the actuator.

  • Pilot Pressure —  Auxiliary pilot pressure ports direct system hydraulic pressure to other system functions.

  • Pressure Control — An internal pressure control solenoid valve allows you to turn hydraulic pressure on and off via the system control electronics.

  • Independent Pressure Control — Complete and independent control of hydraulic pressure provided to individual  stations while operating from a single hydraulic source.

  • Smooth Pressure Transitions — The effects of rapid removal or application of high pressure are minimize with smooth, controlled transitions between off, low, and high pressure modes.

  • Enhance safety — Predictable pressure transitions and rapid dump hydraulic pressure unloading in the event of an abnormal condition reduce unexpected actuator movement  and protect the specimen, test system and personnel.

  • Up to Four Stations — A maximum of four independent control stations can be provided on each 21 and 22 Series HSM.

  • Filtration — Filtration at the manifold prevents the passage of dirt particles that can enter the hydraulic system when adding hydraulic fixtures or opening hydraulic lines.