Durable Rack And Pinion Pneumatic Actuator , High Performance Control Valve Actuator

► Pneumatic rack and pinion actuators

1.  Introduction – Pneumatic rack and pinion actuators

1.1. Identification

The Apollo Rack and Pinion actuators are available as double-acting or spring-return versions. They are designed to use standardized interfaces for solenoid, switch box, or positioner mounting (NAMUR).

The valve interface is equipped with an insert in the pinion bottom that allows for ISO 5211 mounting. The springs in the spring-return version allow a fail action in case of loss of air supply pressure (fail-to-close or fail-to-open).

Item	Description
1	Top auxiliaries interface ( NAMUR)
2	Solenoid Interface (NAMUR)
3	Valve interface with ISO 5211 patterns and insert drive
4	Spring-return actuators with springs
5	Double-acting actuators with no springs
6	High end caps for double-acting and spring-return models up to size -400
7	Low end caps for double-acting models, sizes -400 and larger

 2. Specifications – Pneumatic rack and pinion actuators

Table 1: Pressure Range

Actuator Type	Spring Quantity	Pressure
Double-Acting	n/a	2-8Bar
Spring Return	10 pcs	5bar
	8 Pcs	4bar

Table 2: Operating Media

Actuator Type	Operating Conditions
Double-Acting & Spring Return	Air, dry or lubricated & inert gas
	Dew point at least 10°C below ambient temperature
	For sub-zero applications, take appropriate measures
	Mentioned pressure levels are “gauge pressures”

Table 3: Temperature Range

Actuator Type	Temperature
	°F	°C
Standard	-4° – 176°	-20° – 80°
Low Temperature	-40° – 176°	-40° – 80°
High Temperature	-4° – 248°	-20° – 120°

 3. Installation – Pneumatic rack and pinion actuators

This section explains:

· The “Failure Modes” of an actuator.

· In which position the actuator will end after a failure.

· Principles of operation:

o Solenoid operation

o Double acting and Spring return operation

· Assembly codes.

· Actuator to valve assembly

3.1. Failure Modes

3.1.1. Valve Rotation

For the following paragraphs, we assume that the valves rotate as

indicated in Figure 4.

3.1.2. Position after Failure

The position of the actuator after a failure depends on the:

· Principle of operation

· Assembly (code) of the actuator

· Type of failure