Schubert & Salzer – Type 8021 Sliding Gate Control Valve Series

Overview

The Schubert & Salzer Type 8021 is a sliding gate control valve series with integrated positioner, available in two platform variants — the GS3 and GS4 — for modulating control of neutral and aggressive media in chemical, process engineering, and plant construction applications. Both series feature an integrated top-mounted positioner and wafer-type body for compact installation between standard flanges, with the Type 8049 digital positioner and Type 8047 pneumatic/electro-pneumatic positioner supported on both. The GS3 covers sizes 1/2″ to 10″ with pressure ratings up to 1,450 psi and ANSI #600 in stainless steel, carbon steel, and Alloy C276 bodies. The GS4 extends pressure capability to 2,321 psi and ANSI #900 for 1″–3″ sizes, with 316Ti stainless steel construction and size-dependent pressure ratings.

The sliding gate operating principle provides high dynamic response due to short stroke, quiet operation, and the ability to handle high differential pressures with compact actuators at greatly reduced energy consumption compared to conventional control valve designs.

Features & Benefits

• Integrated top-mounted positioner standard on both GS3 and GS4 — compatible with Type 8049 digital positioner and Type 8047 pneumatic/electro-pneumatic positioner
• High dynamic response due to short stroke — quiet operation with significantly reduced actuating forces on the throttle element
• Greatly reduced energy consumption compared to conventional control valves due to short stroke and low actuating forces
• High Cv values relative to valve size from the sliding gate operating principle
• GS3: three body material options — stainless steel (CF8M/316Ti), carbon steel (WCB/CF8M), and Alloy C276 — for compatibility across neutral to aggressive media
• GS4: 316Ti stainless construction rated to 2,321 psi and ANSI #900 in 1″–3″ sizes — highest pressure ratings in the Type 8021 lineup
• GS3: wafer-type and threaded connection options; GS4: wafer-type with space-saving screwed wafer for flanges per ANSI B16.5
• Low weight compared to competitive valves in equivalent pressure and size ratings
• Metal bellows accessory available for zero-emission stem sealing
• GS3: TA-Luft / ISO 15848-1, CRN Certificate, EC and UKCA Declarations, and SIL manufacturer’s declaration available
• Optional ATEX non-electrical approval (II 2G Ex h IIC T6…T1 X Gb; II 2D Ex h IIIC 85°C…530°C X Db) for both GS3 and GS4

Technical Specifications

• Size: 1/2″ – 10″ (GS3); 1″ – 10″ (GS4)
• Pressure (GS3): 145/580 psi; 1,450 psi; ANSI #150; ANSI #300; ANSI #600
• Pressure (GS4): 1″–3″: 2,321 psi, ANSI #900; 4″–6″: 1,450 psi, ANSI #600; 8″–10″: 580 psi, ANSI #300
• Body material (GS3): Stainless steel CF8M / 316Ti cover; Carbon steel WCB / CF8M cover; Alloy C276
• Body material (GS4): Stainless steel 316Ti; Seat set: STN2, STN3 (1″ or 2″)
• Media temperature: -76°F to 662°F (special versions available on request)
• Actuator: Integrated top-mounted positioner; NAMUR standard positioner mounting also available
• Connection: Wafer type; Threaded (GS3 only); Screwed wafer for flanges per ANSI B16.5 (GS4)
• Media compatibility: Neutral and aggressive fluids, liquids, gases
• ATEX (optional, both series): II 2G Ex h IIC T6…T1 X Gb; II 2D Ex h IIIC 85°C…530°C X Db

Applications

• Modulating control of neutral and aggressive media in chemical and process engineering plants
• High-pressure control applications up to 2,321 psi and ANSI #900 (GS4, 1″–3″)
• High differential pressure control with compact actuators and reduced energy consumption
• Applications requiring low weight and space-saving valve construction vs. conventional control valves
• Zero-emission control applications requiring metal bellows stem sealing
• Low-emission process plants requiring TA-Luft / ISO 15848-1 compliance (GS3)
• Hazardous area control installations requiring ATEX non-electrical approval
• Applications requiring CRN certification (GS3)
• Applications requiring SIL compliance (GS3)

Models / Configurations

• Type 8021 GS3 – Sliding gate control valve with integrated positioner for neutral and aggressive media. Sizes 1/2″–10″, up to 1,450 psi and ANSI #600. Body options: stainless steel CF8M/316Ti, carbon steel WCB/CF8M, and Alloy C276. Wafer-type and threaded connections. Full approvals suite including CRN, TA-Luft, SIL.
• Type 8021 GS4 – High-pressure sliding gate control valve with integrated positioner for neutral and aggressive fluids. Sizes 1″–10″, with size-dependent pressure ratings up to 2,321 psi and ANSI #900 (1″–3″). Stainless steel 316Ti body with STN2/STN3 seat set options. Screwed wafer-type body per ANSI B16.5. TA-Luft / ISO 15848-1 approved.

Type 8021 Accessories

Positioners

• Type 8049 Digital Positioner – Digital positioner for the Type 8021 in 2-wire and 4-wire configurations. Available variants include Ex-proof, IO-Link, and integrated process controller (IPC) versions.
• Type 8047 Pneumatic & Electro-Pneumatic Positioner – Pneumatic and electro-pneumatic positioner in 2-wire and Ex configurations. Also available with NAMUR standard mounting.

Additional Accessories

• Metal Bellows – Metal bellows stem seal for zero-emission applications requiring enhanced fugitive emissions control.
• Limit Switch – Position feedback accessory providing open/close status signal for process monitoring and control integration.
• Position Feedback – Analog or digital position feedback device for continuous valve position monitoring.
• Manual Override – Allows manual operation of the valve independent of pneumatic supply for maintenance or emergency use.
• Pilot Valve – Solenoid pilot valve for pneumatic actuation control.

Documentation