MTS Series 290 Hydraulic Service Manifold Specifications

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MTS Series 290 Hydraulic Service Manifolds

The MTS Series 290 Hydraulic Service Manifolds (HSM) are connected in the hydraulic lines between the hydraulic power supply (HPS) and the servo valves to perform four basic functions:
  • All models provide system fluid filtration in addition to that provided by the hydraulic power supply.
  • All models provide accumulators in both pressure and return lines to provide energy storage and minimize pressure fluctuations.
  • Most models have a separately filtered outlet with an accumulator to operate the pilot stage of high flow or high performance two stage servo valves.
  • Some models have a hydraulic control valve (operated from the system control panel) to provide slow turn on, low pressure, and fast pressure unloading.
  • Complete, independent pressure control of individual channels or systems operating form a single hydraulic power supply
  • Fast pressure unloading function that quickly removes pressure applied to the servovalve in the event of an abnormal condition
  • Auxiliary pressure and return ports for operation of auxiliary actuators and for versatility in system hookups
  • Push-to-read pressure gauge that allows monitoring of output pressure
  • Port that allows drainage of the main filter before general maintenance is performed, to reduce hydraulic fluid spills
  • Smooth pressure transitions from off to low to high, and from hight to low
  • Descriptions of Functions


    An inlet pressure (main) filter provides 74 micron (absoloute) filtration to the servovalve(s) and actuator. This filter minimizes contamination to the servovalve(s) and actuator by large particles that might enter the system between the Hydraulic Service Manifold. It must be used in conjunction with a 10 micron (or finer) filter on the hydraulic power supply.

    Models equipped with pilot pressure also contain 3 micron (absolute) filters. These filters are equipped with pop-up dirty element indicators in conjunction with bypass valves.

    A check valve in series with each filter minimizes hydraulic fluid backflow through the filter.


    Dynamic operation of servo hydraulic systems can create large pressure pules in the hrdraulic circuit. Piston type, dry nitrogen charged accumulators provide energy storage in pressure lines, and reduce pressure fluctuations and line movement in pressure and return lines.

    Pilot Outlet

    Some models have a seperate outlet for operating the pilot stage of the high flow, two stage servovalves used in most high flow applications. The outlet feature provides additional filtration of 3 microns (absolute) and an accumulator to minimize rapid pressure changes that could adversely affect the operation of the servovalve pilot stage.

    Bypass Manifold

    Some models are equipped with a bypass manifold instead of a control manifold. The bypass manifold completes the pressure circuit path which is opened when the control manifold is not present. It also blocks the port which is used for fast pressure unloading when the manifold is in place.

    Hydraulic Control Valve

    A solenoid operated pressure control valve manifold, which replaces the bypass manifold on some models, gives the operator complete control of flow and high pressure and provides a fast pressure unloading function

    The control valve, which is operated from the system control panel, has three modes: off, low pressure, and high pressure. These modes are described:


    In the off mode, the main pressure outlets are blocked and isolated form the servovalve(s) except for pilot pressure, which continues to supply the servovalve pilot stage maintain control.


    In the low pressure mode, ouput pressure us reduced by an adjustable valve, within a range of 0 to 3,000 psi (normal full system pressure). Low pressure mode ius useful checking the ststic system operation or mounting a specimen


    With low pressure applied, high pressure can be selected. Output pressure increases smoothly until the pressure setting of the hydraulic power supply is reached. Normally, the high pressure setting is 3,000 psi (20.7 MPa). Returning to low pressure at this point is also a gradual process.

    Fast Pressure-Unloading Function

    The models that are equipped with a hydraulic control valve provide a fast method of depressurizing the hydraulic line(s) beyond the Hydraulic Service Manifold. This fucntion provides a controlled direct connection between the main pressure line and return line through the hydraulic control valve. Approximately 150 milliseconds are required to complete depressurization cycle.

    The fast pressure-unloading function is activated by any of the following conditions:
  • The emergency stop button on the system control panel or remote control station is pushed.
  • The interlock circuit on the system control panel opens, indicating that an abnormal condition has been detected somewhere in the system.
  • Electrical power failure occurs. The normal position of the hydraulic control valve, without electrical power applied, is pressure unloading position.