Fisher™ 667 Diaphragm Actuator

The Fisher™ 667 Diaphragm Actuator is a reverse-acting, spring-opposed pneumatic actuator designed for sliding-stem control valves. Unlike the Fisher 657, which is direct-acting, the 667 actuator applies signal pressure beneath the diaphragm to push the stem upward, while the spring provides the opposing downward force. This reverse-acting design is widely used in applications where fail-safe positioning requires the valve stem to extend on air failure.

Key Features

• Reverse-Acting Design – Provides alternate fail-safe action to meet specific process safety requirements.
• Durable Construction – Heavy-duty cast iron or steel housings ensure long-term reliability in demanding environments.
• Consistent Performance – Large diaphragm area delivers high thrust and stable, linear travel response.
• Fast Control Response – Compact pressure chamber reduces air volume for quicker actuation.
• Flexible Options – Available with adjustable travel stops, handwheels for manual operation, and direct mounting capability for Fisher FIELDVUE™ digital valve controllers.
• Broad Range – Supports multiple signal pressure ranges (3–15 psig, 6–30 psig) and offers cold-service construction for extreme environments.

Variants / Related Models

• 667 (Standard) – Reverse-acting spring-opposed actuator, available in a wide range of sizes.
• 667-4 – Extended-travel version for larger valve strokes.
• 667NS / 667NS2 – Special-service versions with enhanced construction for challenging conditions.
• 667R – Reverse-acting model with specific configurations for high-thrust requirements.
• 657 Series – Direct-acting counterpart to the 667, offering alternate fail-safe operation.

Advantages

• Provides reliable reverse-acting operation to ensure correct fail-safe positioning.
• Offers high thrust and precise control for both throttling and on/off service.
• Wide selection of sizes and configurations to match process conditions.
• Proven integration with Fisher FIELDVUE™ digital valve controllers and accessories.

Why Choose HKXYTECH

HKXYTECH supplies Fisher™ 667 Diaphragm Actuators with guaranteed authenticity and full technical support.

• 100% Original – Genuine Fisher/Emerson actuators.
• Competitive Pricing – Cost-effective solutions tailored to customer budgets.
• Fast Delivery – Short lead times and dependable stock availability.
• Expert Support – Professional guidance, documentation, and after-sales service.

By partnering with HKXYTECH, customers gain access to reliable Fisher actuator technology and a trusted supplier focused on minimizing downtime, improving safety, and ensuring long-term performance.