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Reference projects

Corrosion-resistant diaphragm actuators for BP refinery in Gelsenkirchen

In Gelsenkirchen, BP operates a complex refinery and petrochemical site producing high-quality gasoline and diesel grades, heating oils & aviation fuels. The refinery in Scholven also produces petrochemical products such as ethylene and propylene, for further processing into plastics.

Due to the corrosive environment in the industrial plants, extremely robust components are required. In this context, A. Hock supplied diaphragm actuators including adaptation to the control valves from Emerson/Sempell. The pneumatic valves are now in use at BP in Gelsenkirchen.

Project data

customer: BP refinery Gelsenkirchen-Scholven

industry: oil and gas (refinery)

services: delivery of pneumatic diaphragm actuators and adaption for Emerson/Sempell control valves

products used: diaphragm actuators series 2000 type 2116

The requirement - Strong diaphragm actuator for Sempell valve

To meet the high process requirements, Emerson/Sempell works with the AIR&SPRING design tool for A. Hock diaphragm actuators. The actuators are to be delivered to the end customer with adaptation for pneumatic valves.

Context: Sempell valves are designed for the toughest environments and offer the highest reliability for any application in industrial processes.

The challenges - Corrosive refinery environment

The actuators require the special C3H coating due to the corrosive atmosphere on site. According to the DIN EN ISO 12944 corrosivity category, "C3" means an industrial atmosphere with moderate SO2 contamination. The "H" stands for a durability or a protection period of more than 15 years.

The result - SIL2 diaphragm actuators with special coating

A total of six pneumatic diaphragm actuators of function class SIL2 were delivered to the customer. Compared to piston actuators, diaphragm actuators have the great advantage that they are available in smaller sizes and are less expensive. The special C3H coating protects the actuators from the high loads in the refinery.

Products used

6 x pneumatic diaphragm actuators type 2116

  • Diaphragm area of 1200 cm², nominal stroke 100 mm
  • Top-handwheel
  • Functional safety class SIL2
  • Special coating according to C3H DIN EN ISO 12944

Do you have further questions about pneumatic diaphragm actuators?

Then please feel free to contact our product experts.


David Raitz

David Raitz

Technical Sales

I’m your contact for projects and enquiries in the field of valve technology as well as measurement and control technology. Contact me for the correct dimensioning of control valves and actuators as well as for valve service concepts.