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:

Ensuring occupational health and safety in mining
Analytical Instrumentation & Environmental Monitoring
Probe Integrated Mining Technologies (Probe IMT) has partnered with M3SH Technology to offer state-of-the-art environmental monitoring solutions that address these dual requirements.

Read more...
Sustainability of surface water
Endress+Hauser South Africa Analytical Instrumentation & Environmental Monitoring
The sustainability of surface water is critical for South Africa’s economic development, social well-being and environmental health. Endress+Hauser has a full range of liquid analysis sensors and transmitters to measure important parameters and has an excellent global track record in water and wastewater process plants and various surface and industrial water monitoring sites.

Read more...
Keeping an eye on invisible radiation
Omniflex Remote Monitoring Specialists Analytical Instrumentation & Environmental Monitoring
At its peak in 1994, the energy generation capacity of the UK’s nuclear power stations was 12,7 GW across 16 plants. In 2024, the capacity has fallen to around 5 GW, and the number of stations is down to nine. However, this is far from the end of the story as spent nuclear fuel remains radioactive for centuries, and requires rigorous safety processes to safeguard against leaks.

Read more...
Effective dust control in sugar processing
Analytical Instrumentation & Environmental Monitoring
BLT WORLD specialists work in conjunction with the global ScrapeTec team to offer dependable solutions for specific problems at the transfer points of conveyor systems in many industries where dust and material spillage are concerns, including the sugar sector.

Read more...
A benchmark for lubricant reliability in mining
Analytical Instrumentation & Environmental Monitoring
According to Craig FitzGerald from ISO-Reliability Partners, mines can save R500 000 or more on their yearly mill cleaning costs, while electricity consumption can be reduced by up to 12%, and lubricant consumption lowered up by up to 60% when using Bel-Ray Clear Gear lubricant.

Read more...
Safeguarding precision in industrial radiometric measurements
Mecosa Analytical Instrumentation & Environmental Monitoring
In the complex landscape of industrial plant operations, precision is paramount, especially when it comes to weld inspections to test for structural integrity of pipes. Berthold has the ideal answer to this challenge – X-Ray Interference Protection.

Read more...
Valves for severe service
Valve & Automation Editor's Choice Valves, Actuators & Pump Control
Valve specialist, Valve & Automation supplies total valve and control solutions to a wide range of key process industries across southern Africa. Chemicals and pulp and paper are top of its list of industries with demanding process conditions.

Read more...
New indoor air quality monitor
RS South Africa Analytical Instrumentation & Environmental Monitoring
RS South Africa has available a new indoor air quality (IAQ) monitor that provides continuous, easy-to-read, and accurate real-time monitoring of air quality in indoor environments.

Read more...
A quick guide to disinfection
Endress+Hauser South Africa Analytical Instrumentation & Environmental Monitoring
The distribution system in a drinking water network provides a reliable supply of high-quality water to consumers. Endress+Hauser’s range of robust, low-maintenance sensors are ideal for monitoring disinfectant levels in the water.

Read more...
Multi-parameter measuring system for water quality monitoring
KROHNE Analytical Instrumentation & Environmental Monitoring
Monitoring different parameters in water treatment processes can lead to a situation where different measuring points are scattered across the plant.

Read more...