STEVI straight-through control valves

STEVI® 422/4621.0 globe control valves are designed to control and manage liquids, vapors and gases in a variety of processes.

Operating principle and service life

The ARI series of control valves are designed for use with pneumatic and electric actuators. Depending on the intended application, the throttle element can be configured in one of the following styles:

• pressure reducing valve
• conventional parabolic shutter device,
• perforated reinforcement.

Liquid flow through the valve is in the opposite direction from the closed position. Liquids flow toward the closed position when the valve is perforated, while gases and steam flow in the opposite direction.

For a valve with a perforated shutter and flow directed toward closing with a pneumatic actuator, it is necessary to increase the drive force to prevent vibration in the close position. If the actuator power is insufficient, a pressure-reducing device is installed, taking into account operating conditions.

Depending on operating conditions, the average lifespan executive control valve The service life before the first major overhaul can reach 100,000 cycles. With proper maintenance, the estimated service life exceeds 5 years of intended use. The service life can be extended with the manufacturer's approval.

The service life of the fittings depends on several interrelated factors:

• types, concentration and aggressiveness of the environment used,
• exposure to atmospheric conditions.

Temperatures, operating frequency, repair, maintenance and sealing materials of the working fluid penetrating through the valve must comply with regulatory documents.

Requirements for the location and installation features

The technician ensures adequate space around the installation site for maintenance and dismantling. Shut-off valves are installed upstream and downstream of the valve to allow for repairs and maintenance without completely draining the system.

The manufacturer recommends vertical installation of the valve with the actuator positioned above. When installed horizontally, the permissible actuator weight, depending on the spindle dimensions, is 55 kg for DN 200-250.

Mounting or removing the actuator from a valve that is exposed to temperature and pressure is prohibited. Rotating the valve in its seat under pressure during installation is prohibited.

Storage and transportation

In unfavorable weather conditions or when stored outdoors, equipment should be mothballed or subject to special protective measures. It's important to remember that chemical vapors, seawater, and other corrosive agents promote and accelerate corrosion.

The varnish primer must not be damaged. It protects against corrosion during storage and transportation at the recommended temperature range of -20°C to +65°C.

If the manufacturer's maximum 15-year shelf life is exceeded, the valve's functionality and performance are tested before commissioning. Maintenance is performed as needed, or the device is replaced with a new model.