Belgas T75 Air Relays

T75 Air Relays

Product Description

The T75 Air Relay is engineered to deliver precise and stable output pressure control using an input signal pressure, even under wide variations in supply pressure and flow demand. Its integrated aspirator tube automatically modulates the air supply valve opening based on flow velocity, ensuring consistent output pressure during changing flow conditions.

Equipped with a balanced supply valve and a rolling diaphragm, the T75 is designed to remain virtually unaffected by fluctuations in supply pressure. The relay features a unitized construction that allows for quick and straightforward maintenance without removing the device from the pipeline. The T75 is available in multiple signal-to-output pressure ratios—including 1:1, 1:2, 1:4, and 1:6—and supports a maximum output pressure of up to 150 psig (10.3 bar).

Ideal for volume boosting, valve motor loading, and low-temperature pneumatic applications, the T75 Air Relay delivers reliable performance and exceptional responsiveness across a wide range of industrial environments.

Applications

• Volume boosting

• Valve motor loading

• Low-temperature pneumatic systems

• High-speed exhaust or return-stroke actuation (High Relief models)

Model Options

Type 75 (Standard Model)

• High precision signal-to-output relay

• Provides strong forward flow performance

• Recommended for general-purpose pneumatic control

Type 75 High Relief Relays

• Designed for extremely fast exhaust (“blowdown”) of output pressure

• Ideal for applications requiring rapid depressurization, such as:

  • Cylinder return stroke actuation

  • Air hoists

  • Systems where fast relief improves control response

Technical Specifications

Pressure Control

• Signal-to-Output Pressure Ratios:

  • 1:1

  • 1:2

  • 1:4

  • 1:6

• Maximum Output Pressure: 150 psig (10.3 bar)

Design Features

• Aspirator Tube: Maintains stable output pressure by adjusting valve opening relative to flow velocity

• Balanced Supply Valve: Rolling diaphragm design ensures minimal effect from supply pressure fluctuations

• Unitized Construction: Allows in-line servicing without removing the relay

• High Forward Flow Capability: Ensures rapid response to changing system demands

• High Relief Option: Provides accelerated exhaust rates for applications requiring fast pressure release