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Accessories For Pneumatic Actuators

 

The basic actuator may be used to open and close the valve, but if more functionality is required then the actuator can be extended by the addition of accessories. These can be used to make the actuator operate faster or slower or to provide position indication or position control to the controller. These are just a small sample of the additional possibilities by El-O-Matic.
 

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Position Indication
For effective valve control the controller needs to know the open/closed state of the valve. The El-O-Matic switch box range provides for every possible requirement for position indication. In addition to the basic versions described below, El-O-Matic supplies 2- or 3-wire proximity switches, reed switches and switches for specific explosion-safe applications.

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HDN Switch Box

A heavy-duty (aluminium alloy) switch box contains a pair of contact micro switches activated by two cams on a shaft driven by the actuator. These signal the full open and closed valve position. Both switches are independently adjustable and terminals are provided for the systems' connection. The switch box is of generous proportions and has two electrical entries so that, with additional terminals, the connection to the actuators' HD switch boxes can be supplied to a waterproof specification, IP 67 to IEC 529, or explosion proof EEx d (European certification), or Class l div 1 group C, D. Class II div 1 group E, F, G. (CSA certification).

LDN Switch Box

 


 
This switch box is suitable for utility applications or process applications under conditions that are less demanding. Functionality is similar to that of the HDN but with a lower level of waterproofing (IP 65) and limited explosion proof versions.

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Solenoid Valve

Solenoid valves provide local open/close control by means of a remote powered electric signal. El-O-Matic supplies industry standard NAMUR solenoid valves for direct mounting on the air connection face of the actuator. These are spring return solenoid valves. On power failure automatically returning the actuator to a pre-set (normally closed) position.
Solenoid valves are of the universal type and may be used on double acting or single acting actuators; the change is made by means of a reversible manifold plate. Standard solenoid valves are provided with a manual override control. As an option, speed control throttles are available fitted at the exhaust ports.

Manual Override Control

The El-O-Matic MO Series declutchalble gear operators offer a simple and reliable method of local manual operation, this may be required during commissioning set up, as emergency control on air failure, or as a local control in the event of controller malfunction. As such when the hand wheel is clutched in, the valve is under local manual control and the remote control is "locked out".

Speed Control Plate

This is used in combination with a NAMUR solenoid valve and serves to provide independent speed control of both the opening and closing strokes. The speed control plate can be used with both single and double acting actuators, but when used on single acting actuators, only the spring return stroke is regulated.

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Breather Block
The breather block is used on single acting actuators and provides corrosion protection of the actuator spring chamber. It should be used on applications where the actuator is located in a corrosive atmosphere that would otherwise be sucked into the actuator during the spring stroke.

The breather block is fixed directly onto the actuator's NAMUR air entry manifold and has a further NAMUR interface so that a suitable solenoid valve may be directly mounted, or for a tubing connection in the case of a remote solenoid valve.
The breather block has a built-in quick exhaust function to improve the spring stroke time. An optional speed control can be provided to regulate this closing time.

Block & Vent Valve

This should be used on applications where on site servicing of the actuator is required and where the actuator needs to be isolated from the control system. It provides a local means of blocking the supply air from the actuator at the same time venting all compressed air from both chambers of the actuator. It may be used for double acting or spring return actuators.
The valve block is fixed directly onto the NAMUR air entry manifold and has a further NAMUR interface so that a suitable solenoid valve may be directly mounted.

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Valve Positioners

 
Positioners are instruments that play a vital part in the processes. They must convert the signals they receive quickly and efficient and respond by regulating the valve to any position between 0 and 100%. The El-O-Matic "Posiflex" positioners are high quality, reliable instruments that form a strong link in modern process-control systems.

Posiflex Positioners
The Posiflex range consists of 2 models, the pneumatic F10 and the electro-pneumatic F20. All models are used in applications in which the pneumatic actuators must be positioned with a high degree of accuracy. The positioners are suitable for single as well as double-acting actuators. They can be used for controlling other movements. All Posiflex positioners are robust with housings of cast aluminium alloy with a finish of epoxy coating. They are highly resistant to external influences. The interior has a modular structure so that it can be adapted quite simply to your specific uses. The various options are described in this brochure.

General Features Posiflex Positioners

  • Provides the ultimate in quick and accurate positioning.
  • Suitable for single acting (spring return) and double acting actuators.
  • High-grade aluminium alloy housing finished with an polyerster pouder coating.
  • Direct and reverse acting.
  • Standard connections in accordance with VDI/VDE 3845 (NAMUR).
  • Modular structure, therefore easy to expand.
  • Suitable for controlling rotating actuators and other rotating movements

Posiflex F10		 Features Posiflex F10
  • Pneumatic-pneumatic model.
  • Simple robust model.
  • Only, mechanical parts.
  • External zero-setting.
  • Waterjet proof.

Posiflex F20		 Features Posiflex F20
  • Electro-pneumatic model.
  • Analog electric signal (4-20 mA).
  • Split-range and reverse-acting setting functions simply adjustable by jumpers.
  • Optional: intrinsically safe execution (II 2 G EEx ib IIc T6)
  • Enclosure IP65 (NEMA4).

 

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Accessories

Gauge block
 
 

 
G 1 and G2 gauge blocks
  • Type G1 is suitable for the Posiflex F10 and gives the actuator's operating pressure and the incoming instrument pressure.
  • Type G2 is suitable for the Posiflex F20 and F40. It provides an indication of the output and of incoming air pressure.

Position transmitters PTF20, PTM
These electronic position transmitters transmits a continuous 4 to 20 mA feedback signal, this reflects the mechanical position of the positioner. These position transmitters are also available in an intrinsically safe execution (II 2 G EEx ib IIC T6).

  • The PTF20 is available as a "Plug-in" option for the F20 positioner.
  • The PTM is available as a "build in" module for F10 and F20 positioners.
  

PNP
Position
Indicator

Position indicators

  • PNP, 3-wire inductive switches.
  • IS2, 2-wire inductive switches. Intrinsically safe variation is available as an option for use in explosion hazardous areas.
  • S2, mechanical end of stroke V3 switches.
  • POT, Potentiometer for continuous resistive feedback signal on the position of the valve.
  

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 WebMaster.ValveAutomation@EmersonProcess.com


Last Updated 03/14/08


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