Ball valves-Valves

Pneumatic and Electric Actuators for Ball Valves

Pneumatic and electric actuators are available for automating ball valves. Pneumatic rotary actuators are particularly common in industrial applications because they typically enable high switching speeds—usually under one second—and operate extremely reliably even with high switching cycles.

Double-acting pneumatic actuators use compressed air to both open and close the ball valve. They are particularly suitable for automated processes involving frequent switching operations. Single-acting pneumatic actuators also feature a spring-return mechanism. In the event of a compressed air failure or power outage, the actuator automatically moves to a defined NC (normally closed / spring-closing) or NO (normally open / spring-to-open) safety position, thereby increasing the system’s operational safety.

Electric rotary actuators offer an alternative when no compressed air supply is available at the application site. They enable convenient electrical control and can be easily integrated into modern control and automation systems. Depending on the actuator size, the switching time ranges from 11 to 30 seconds.

Solenoid Valves for Automated Ball Valves

Solenoid valves can be used to control the compressed air supply for pneumatic actuators. For double-acting pneumatic rotary actuators, 5/2-way solenoid valves are typically used. These control the compressed air for both directions of movement and enable fast and precise switching of the valve.

For single-acting actuators with spring return, on the other hand, 3/2-way solenoid valves are typically used. They control the compressed air in one direction of movement, while the return is provided by the integrated spring. This supports safety concepts in which the valve is designed to automatically assume a defined position in the event of a power or compressed air failure.

Limit Switch Boxes for Position Monitoring

In automated systems, ball valves are often equipped with limit switch boxes. These detect the valve’s current position and reliably indicate whether the ball valve is in the open or closed position. The signals can be transmitted directly to PLCs or process control systems, thereby enabling continuous monitoring of the system’s status.

In addition, many limit switch boxes feature a clearly visible optical position indicator located directly on the device. Through position feedback, limit switch boxes increase process reliability, simplify maintenance work, and contribute to higher plant availability.

Comprehensive Solutions for Shut-off and Automation Applications

Modern ball valves can be combined with pneumatic or electric actuators, solenoid valves, limit switch boxes, and other accessories to create fully automated valve solutions. This enables plant operators to safely automate processes, monitor operating states, and sustainably increase the operational safety of their plants.

From low-pressure ball valves f&standard applications to high-pressure ball valves for pressures up to 500 bar, solutions are available for virtually every industrial shut-off and control task.

How It Works

In a needle valve, the flow rate is varied by the position of the valve cone relative to the valve seat. Turning the stem moves the metal valve cone axially, thereby changing the free flow cross-section. This allows the flow rate to be precisely adjusted and limited. If the valve cone is moved all the way toward the valve seat, the valve can be used to shut off the flow of the medium.

Needle valves are therefore suitable for use both as flow control valves and as shut-off valves.

Advantages

• Vorteile der Schwer Nadelventile
• Mengenregelung und Absperrung mit einem Ventil
• Feinfühlige Durchflussregulierung durch den metallischen Ventilkegel
• Hohe Druckbeständigkeit: je nach Ausführung bis zu 400 bar
• Verschiedene Anschlussvarianten für unterschiedliche Rohrleitungssysteme
• PTFE-Dichtpackung zur Abdichtung der Spindel nach außen
• Standard- und ASP-Ausführung für unterschiedliche Anforderungen an das Medium
• Kompatible Ventilpatronen: Standard- und ASP-Patrone können im gleichen Ventil-Grundkörper eingesetzt werden
• 100-%-Funktionskontrolle auf Dichtheit vor Verlassen des Schwer Fittings Werks

Applications

Needle valves are used wherever fluids need to be precisely regulated, throttled, or shut off. Typical applications include, for example:

• Machinery and plant engineering
• Industrial piping systems
• Measurement and control technology
• Process and process engineering
• Compressed air and gas applications
• Systems with liquid media
• Applications with high operating pressures

For aggressive or crystallizing media, the ASP version may be a suitable alternative to the standard version.

Selecting the Right Needle Valve

When selecting a needle valve, the technical requirements of the application should be taken into account as precisely as possible.

• Function: Flow control, throttling, or shutoff
• Medium: Liquid or gas, as well as chemical properties
• Operating pressure: Up to 400 bar, depending on the model
• Temperature: Permissible temperature range for the respective version
• Connection type: Female thread or cutting ring connection
• Thread sizes: G 1/8" to G 2"
• Pipe size: 6L to 28L or 6S to 25S
• Valve version: Standard or ASP
• Seal material: PTFE packing
• Material: Depends on the medium and operating conditions

The specific suitability of the needle valve must be verified based on the respective product data and operating conditions.

Needle Valves with Female Threads

Needle valves with female threads in accordance with DIN ISO 228 are available in thread sizes ranging from G 1/8" to G 2".

This design is suitable for direct integration into corresponding piping and system components with threaded connections.

Needle Valves with Cutting Ring Connection

Needle valves with a cutting ring connection in accordance with EN ISO 8434-1 are available for connection to metric piping. Available pipe sizes:

• Light series: 6L to 28L
• Heavy series: 6S to 25S

This means that needle valves are available for a variety of pipe sizes and pressure requirements.

Needle Valves for High Pressures

Depending on the size, medium, and temperature, heavy-duty needle valves can be used for pressures up to 400 bar. The maximum permissible operating pressure depends on the specific valve design and operating conditions. Therefore, size, medium, temperature, and pressure must be taken into account when selecting a valve.

Sealing the Spindle

PTFE packing is used in needle valves to seal the stem against the surrounding environment. The packing prevents the medium from leaking along the stem and ensures that the valve is sealed off from the outside. The design position of the spindle adjustment thread distinguishes the standard version from the special ASP version.

Standard Version

In the standard version, the spindle adjustment thread is located in the fluid-carrying section of the valve.

This design is suitable for numerous standard applications in which the properties of the medium do not require a special spindle thread design.

ASP version for corrosive and crystallizing media

For applications involving highly aggressive or crystallizing media, Schwer offers the special ASP version. In the ASP version, the spindle adjustment thread is located outside the media-contacting area.
As a result, the spindle thread does not come into direct contact with the medium.

This reduces the risk that aggressive or crystallizing media will damage the thread or cause deposits to form in the threaded area.
This reduces the risk of the spindle thread seizing or becoming stuck, particularly when handling critical media.

Standard and ASP valve cartridges in the same housing

A particular advantage of this design is the compatibility of the valve cartridges. Standard and ASP valve cartridges can be used in the same valve body.

The materials and dimensions are coordinated so that both variants can be used within the corresponding valve body. This allows the valve design to be adapted to the specific requirements of the application.

Leak and Functional Testing

Before leaving the factory, every needle valve undergoes a 100% functional leak test.

This ensures that the valves meet the specified requirements for function and leak tightness.