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Volume Boosters and Air Relays

Products > Pneumatic Controls

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Type 200 Precision Air Relay

Pilot operated, multi-stage 1:1 relay

The Type 200 Precision Air Relay is a pilot operated, multi-stage 1:1 relay with a positive and negative bias adjustment capability. It accurately reproduces a signal pressure plus or minus the bias setting with consistent reliability. Output control and stability are maintained through a high gain servo balanced control mechanism which is activated by a highly sensitive stainless steel measuring capsule.

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Type 250 Lock-up Air Relay

Reliability for fail in place applications

The ControlAir Type 250 Lockup Air Relay is a reliable unit for fail in place applications of control valves when air supply drops below acceptable pressure levels. Valve or damper position is maintained by capturing air pressure inside the diaphragm chamber (or piston cylinder) of the actuator, when the supply pressure falls below the desired set value.

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Type 600 Volume Booster

Meet high flow requirements with a low flow pneumatic signal

The Type-600 ratio relay volume booster is designed to use a pnuematic signal to produce an output pressure which has high flow capacity and can be amplified. This unit is most useful for systems requiring the conversion of a low flow control signal to the higher flow requirements of an operating system. Using an independent supply pressure for greater volume, the Type-600 relays up to 50 SCFM flow capacity to a final control element such as a valve actuator. The standard signal to output ratio is 1:1, however, the Type-600 is also available with an amplified ratio of 1:2, 1:3 and 1:6.

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Click on image to download pdf brochure

Type 650 Positive Bias Relay

Output pressure from input signal plus a preset bias

The Type-650 positive bias relay is a signal operated regulator that provides an output pressure that is the sum of the input signal pressure plus a preset bias. The unit allows flow capaci ties up to 50 SCFM with minimal pressure drop. An aspirator tube at the output maintains the set pressure under varying flow conditions by causing the main supp!y valve to open and close proportionally to the flow demand. There is a choice of four adjustment ranges for the positive bias settings. This unit is most often used for conversion of a low flow control signal to the higher flow requirements of an operating system.

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Type 6000 Volume Booster

High Flow Capacity in a Rugged Casing

The Type 6000 Volume Booster is a one-to-one signal to output relay that, when used with a positioner/actuator, is designed to increase the stroking speed of control valves. A large input signal change to the volume booster delivers high volume, fast action throttling control. An integral bypass valve provides system stability while allowing normal positioner airflow and normal valve actuation with small input changes. If the volume booster is to be used for on/off control valves, the bypass valve can be closed to optimize stroking speed. The Type 6000 is available in aluminum or 316 stainless steel construction.

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Mite 70

Snap-acting control relay with manual reset

Set to trip on either an increasing or decreasing control signal, the Mite 70 will vent one port to atmosphere while it locks up the pressure in a second line. The tripped position is then held indefinitely until the control signal is restored and a manual reset button is pushed. The trip point is adjustable from 1 to 100 psi with a simple screw stem. The Mite 70 can also be tripped on demand from a separate remote signal. Use the Mite 70 to open safety valves in emergency situations, trigger an alarm while locking up a valve or actuate diaphragm motor valves, air cylinders or other pneumatic actuators.

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Super Mite 71L/71H

High pass or low pass pneumatic selecting relay

The Super Mite 71 will automatically select the higher or lower of two pneumatic inputs and pass it downstream while blocking the other. Capable of almost instantaneous selection, the Super Mite 71 can separate pressure differentials as low as a tenth of a psi. Although ordered as either high or low pass, the Super Mite 71 can easily be converted in the field from one to the other. The Super Mite 71 can be relied on to open or close valves when a signal pressure drops or rises past a determined value. They can also be used to prevent a valve from opening or closing beyond a critical point.

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Super Mite 74

Snap-acting control relay with integral 3-way valve

The Mite 74 combines the Mite 70 control relay with a precision 2-way or 3-way valve in a single compact package. Either an increasing, decreasing or remote signal can be used to channel air as needed. The Mite 74 can also be used in combination with either of the Super Mite 71’s so that it will trip when either of two signals drops or rises beyond a set pressure. Once tripped, the Mite 74 will hold its settings until the proper control signal is reestablished and the reset button is pushed.

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Mite 85

Snap-acting 3-way valve with two trip points

The Mite 85 allows you to establish two adjustable trip points that control flow through a 3-way valve. An increasing signal that exceeds the high trip point will open “I” port to “H”. A decreasing signal pressure that drops below the low trip point will vent port “H”. This switching action is reversible and repeatable without having to manually reset. Use the Mite 85 to passively switch to a secondary controller in case the primary system fails.

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