Description
Description
Overview
The ControlAir Mite 85 Air Relay is a compact, snap-acting 3-way pneumatic valve designed to switch automatically between two states based on adjustable high and low pressure trip points. It provides crisp, repeatable switching without manual reset, making it ideal for automatic valve control, backup-controller activation, pressure-limit control, and pneumatic logic systems.
The Mite 85 allows two trip points to be set within a 3 to 15 psig signal range. The adjustable span between the high and low trip points can be set from 1.5 to 6 psig. When signal pressure rises to the high trip point, the relay connects the supply port to the common outlet. When signal pressure falls below the low trip point, the supply closes and the common outlet vents.
Its fully pneumatic, snap-acting design eliminates the need for electrical power or manual resetting. The Mite 85 can directly control a pneumatic valve or be combined with other Mite Series relays to create dependable pneumatic decision-making and failover logic.
Key Features
- Snap-acting 3-way pneumatic relay
- Two independently adjustable trip points
- Trip-point adjustment range from 3 to 15 psig
- Adjustable span from 1.5 to 6 psig
- Automatic switching without manual reset
- Crisp and repeatable state changes
- Automatically activates a backup controller when the primary signal fails
- Can directly control pneumatic valves
- Suitable for pneumatic logic systems
- Supply pressure range from 3 to 50 psig
- Compact design for high-density installations
- Passive pneumatic operation requires no electrical power
- Suitable for air or compatible gas service
- Rugged construction for industrial applications
- Designed for safety, alarm, and process-control functions
Performance Characteristics
- Valve Function: Snap-acting 3-way pneumatic valve
- Operating Signal Range: 3 to 15 psig
- Number of Adjustable Trip Points: Two
- Maximum Adjustable Span: 6 psig
- Minimum Adjustable Span: 1.5 psig
- Supply Pressure Range: 3 to 50 psig
- Maximum Pressure Rating: 90 psig
- Operating Temperature Range: -40°F to 180°F (-40°C to 82°C)
- Port Connections: Tapped for 1/4″ NPT with 1/8″ internal ports
- Approximate Dimensions: 2.5″ diameter × 6.68″ high
- Approximate Weight: 2 lb (0.91 kg)
- Materials: Aluminum, plated steel, neoprene, brass, and stainless steel
- Reset Requirement: None
- Operating Medium: Air or compatible gas
When the signal pressure at port A is below the high trip set point, supply pressure at port I is blocked and the common outlet at port H is open to the vent at port G. When signal pressure reaches the high trip point, supply at port I opens to port H. This condition remains until signal pressure falls below the low trip set point, at which point supply closes and the outlet vents through port G.
How to Select the Right Configuration
Selecting the correct Mite 85 configuration depends on supply-pressure range, desired high and low trip points, span requirements, and how the relay will be integrated into the pneumatic control system.
- Select the low-supply configuration when supply pressure is below 50 psig.
- Select the high-supply configuration when supply pressure is between 50 and 90 psig, subject to the relay’s ordering requirements.
- Set the high trip point within the 3 to 15 psig operating-signal range.
- Set the low trip point below the high trip point with a span of at least 1.5 psig.
- Do not exceed the maximum 6 psig span between trip points.
- Use the Mite 85 as a direct-control relay when the common outlet will operate a pneumatic valve.
- Use the Mite 85 with other Mite relays when a more complex pneumatic logic sequence is required.
- Confirm that the supply-pressure range and valve-actuator requirements are compatible.
- Verify the required venting arrangement before installation.
For additional guidance:
Applications
The Mite 85 is used where a pneumatic system must switch automatically between two operating states based on defined high and low pressure limits.
- Automatic backup-controller activation
- Direct pneumatic valve control
- High- and low-pressure limit control
- Failover control systems
- Pneumatic logic circuits
- Pressure alarm systems
- Safety shutdown systems
- Process interlocks
- Oil and gas control systems
- Chemical processing equipment
- Gas-field controls
- Pharmaceutical process systems
- Utility-air control systems
- OEM pneumatic equipment
Explore more applications:
Models & Configurations
Base Model
- Mite 85 = Snap-acting 3-way pneumatic relay with adjustable high and low trip points
Supply Configurations
- Low Supply = Supply pressure below 50 psig
- High Supply = Supply pressure from 50 to 90 psig
Trip-Point Configuration
- High Trip Point = Adjustable within the 3 to 15 psig signal range
- Low Trip Point = Adjustable below the high trip point
- Minimum Span = 1.5 psig
- Maximum Span = 6 psig
Pneumatic Connections
- A = Operating signal
- B = Supply adjustment
- C = Vent adjustment
- G = Vent
- H = Common outlet
- I = Supply
Use the ordering diagram in the current Mite Series specification sheet or contact ControlAir to confirm the complete ordering code for the required supply-pressure configuration.
Technical Resources
FAQs
What does the Mite 85 air relay do?
The Mite 85 automatically switches a 3-way pneumatic valve between supply and vent states based on adjustable high and low signal-pressure trip points.
How many trip points does the Mite 85 have?
The Mite 85 has two adjustable trip points: one high trip point and one low trip point.
What is the adjustable signal range?
The high and low trip points can be set within a 3 to 15 psig signal range.
What span can be set between the trip points?
The span between the high and low trip points can be adjusted from 1.5 to 6 psig.
What happens at the high trip point?
When the signal reaches the high trip point, the supply port opens to the common outlet.
What happens at the low trip point?
When the signal falls below the low trip point, the supply closes and the common outlet vents.
Does the Mite 85 require a manual reset?
No. The Mite 85 resets automatically as signal pressure moves between the high and low trip points.
What supply pressure can be used?
The operating supply range is 3 to 50 psig, with ordering configurations also identified for higher supply pressures up to 90 psig.
What port size does the Mite 85 use?
The relay is tapped for 1/4″ NPT connections with 1/8″ internal ports.
Does the Mite 85 require electrical power?
No. It is a fully pneumatic, passive relay.
Can the Mite 85 directly control a valve?
Yes. The common outlet can directly operate a compatible pneumatic valve.
Can the Mite 85 be used in pneumatic logic systems?
Yes. It can be combined with other Mite Series decision relays to create pneumatic logic and backup-control systems.
