Analytical Instrumentation & Environmental Monitoring


Universal diaphragm actuator for individual control and regulating functions

March 2000 Analytical Instrumentation & Environmental Monitoring

Even in the electronic age many industrial sectors make effective use of diaphragm actuators with pneumatic or electro-pneumatic positioners as standard actuators.

Short floating speed and high control forces are criterions resulting in high efficiency, reliability and especially long duty lives.

ARCA diaphragm actuators have proven themselves in the industry for more than 50 years. Anywhere where robust design, functional safety and a specially favourable ratio of costs and performance are required.

The function

Air power moves the spindle via the diaphragm against the spring tension. In the case of decreasing air pressure the spring acts in the opposite direction. The initial spring tension can be adapted to the process data by means of the spring tensioning screw. The support is connecting the actuator with the control valve. At the same time the stroke indicator is the connection to the valve spindle.

The proven ARCA modular system enables the user to combine all valve types with the UMA-types.

Important advantages

*niversal – The same type is applicable for both control and regulation functions.

*Reversible – For reversing the control action, all that is needed is to loosen four screws, flip the actuator through 180° and tighten the screws again. Planning errors can still be corrected on the spot without any problems. (Swapping normally open for normally closed).

*Strong forces – The strong springs in a solid casing made of high quality aluminium alloy are providing these actuators with control forces of up to 4 t.

*Long duty life – All parts are designed for approximately one million strokes. A special diaphragm allows a maximum operating pressure of 600 kPa.

*Mounting facilities – Provision is made for the optional inclusion of a support (NAMUR) provided for positioner, limit switches, stroke limitations or field controller. Several instruments can be mounted directly.

*Low-priced hand adjustment – For emergency operation of valves, hand adjustment devices can also be mounted subsequently.

p Few spare parts, little maintenance – The restriction to four sizes only means that only a few spare parts need to be stored for emergency cases.

Valve & Automation

(031) 579 2593



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Eliminate bearing failures in TOVs
August 2021, Valve & Automation , Valves, Actuators & Pump Control
Bearing failures are among the highest root causes of failure in triple offset valves (TOV) for tight shutoff applications. This issue is directly attributed to the need to have metal bearings with very ...

Read more...
Two-gas detection monitor
July 2021, Comtest , Analytical Instrumentation & Environmental Monitoring
New lightweight two-gas monitor offers more accurate alarms and minimises maintenance with a two-year runtime.

Read more...
MAP – making the right choice for gas analysis
August 2021, Elemental Analytics , Analytical Instrumentation & Environmental Monitoring
Modified atmosphere packaging (MAP) is used within the food and pharmaceutical sectors to extend the shelf life of many products that would otherwise deteriorate quickly in the presence of oxygen.

Read more...
Accurate particle matter measurement
June 2021, GHM Messtechnik SA , Analytical Instrumentation & Environmental Monitoring
The PMsense datalogger has particular applications in smart city applications and the monitoring of particle matter pollutants found at industrial sites.

Read more...
24/7 boiler monitoring with the SWAS Compact
June 2021, Endress+Hauser South Africa , Analytical Instrumentation & Environmental Monitoring
Endress+Hauser has developed a compact new steam analysis device for continuous boiler water monitoring.

Read more...
Flexibility for disinfection measuring points
April 2021, Endress+Hauser South Africa , Analytical Instrumentation & Environmental Monitoring
Endress+Hauser’s new modular Flowfit CYA27 flow assembly enables measurement of up to six parameters in process and drinking water.

Read more...
Alkylation processes in petroleum refineries
April 2021, Morton Controls , Analytical Instrumentation & Environmental Monitoring
The SensoTech LiquiSonic is an inline analytical system for determining the concentration of binary liquids directly in the production process.

Read more...
A safe and easy way to check water quality
March 2021, Endress+Hauser South Africa , Analytical Instrumentation & Environmental Monitoring
Ready-to-use water analysis panels from Endress+Hauser ensure water monitoring with minimum effort and maximum reliability.

Read more...
ABB urges adoption of high-efficiency motors to combat climate change
April 2021, ABB South Africa , Analytical Instrumentation & Environmental Monitoring, Electrical Power & Protection
Global electricity consumption could be reduced by 10%.

Read more...
Loop-powered watercut meter
May 2021, SECO Process Instrumentation , Analytical Instrumentation & Environmental Monitoring
The Easz-1 oil/water monitor is a highly accurate online analyser that is installed in a pipe and can be used as a BS&W (basic sediment and water) monitor, or a watercut meter.

Read more...