3/4" True Union Diaphragm Valve (SK-TUDV-007)

The 3/4" PVC True Union Diaphragm Valve (SK-TUDV-007) delivers precise throttling control and reliable shut-off for chemical processing, water treatment, and industrial fluid handling systems where a ball valve or gate valve simply isn't the right tool. Unlike quarter-turn or gate-style valves, a diaphragm valve controls flow by pressing a flexible EPDM diaphragm against an internal weir — completely isolating the actuating mechanism from the process fluid. The result is a valve that handles corrosive chemicals, viscous liquids, and fluids with suspended solids cleanly and without the internal crevices, pockets, or metal components that trap fluid and cause contamination in other valve types.

The weir-type design is a defining characteristic of this valve category. The weir design eliminates entrapped fluids in the valve body and is especially well-suited for handling liquids with suspended solids, viscous fluids, and slurries R&R Products — applications where a ball valve would trap process fluid in the ball cavity or where a gate valve's flat-bottom body would collect solids. When the handwheel is turned to close, the EPDM diaphragm is pressed down onto the weir, creating a clean, crevice-free shut-off with no metal-to-fluid contact.

The true union design is what sets this valve apart from standard diaphragm valves for maintenance-intensive applications. The union end connectors solvent cement permanently into the pipeline — the valve body itself threads out of the unions for complete in-line removal, inspection, diaphragm replacement, or repair without cutting pipe or disturbing the surrounding system. This dramatically reduces maintenance time and downtime in chemical dosing, water treatment, and process piping systems where valve servicing is routine.

The gray PVC body is manufactured to ASTM D1784 Cell Class 12454 for broad chemical resistance across acids, bases, salts, and oxidizing agents up to 140°F. The clear PVC bonnet top provides an easy visual read on the process fluid and the valve's open/close status at all times PVC Fittings Online, and the position indicator gives a precise read on stroke position — important in throttling applications where partial-open settings are used to regulate flow rate. The large multi-turn handwheel provides gradual, controlled diaphragm travel for precise throttling that a quarter-turn ball valve cannot replicate.

All 1/2"–4" true union PVC diaphragm valves in this class are pressure rated at 150 PSI at 70°F non-shock Hayward, with a maximum service temperature of 140°F for PVC construction.

Key Features:

• Weir-type design for clean shut-off with no trapped fluid or internal pockets
• EPDM diaphragm fully isolates valve internals from process fluid — no metal-to-fluid contact
• True union ends for complete in-line valve removal and servicing without cutting pipe
• Socket (slip) end connections for solvent cement installation into PVC systems
• Gray PVC body — ASTM D1784, Cell Class 12454 — broad chemical resistance
• Clear PVC bonnet for visual process monitoring and position indication
• Multi-turn handwheel for precise, stepless throttling control
• Rising position indicator shows exact diaphragm stroke position at all times
• 150 PSI rated at 70°F; 140°F maximum service temperature
• Can be installed in any orientation — horizontal, vertical, or angled

Specifications:

Industries & Applications:

• Chemical Processing & Dosing Systems — The diaphragm valve's defining advantage is complete isolation of the valve mechanism from the process fluid; essential in chemical feed and dosing applications where corrosive or reactive fluids would destroy the internals of a metal or standard ball valve
• Water Treatment & Purification — Used on chemical injection points, filter backwash lines, and treatment chemical feed loops in municipal and industrial water treatment; the weir design handles hypochlorite, acid, and caustic solutions common in water treatment chemistry
• Pool & Spa Chemical Systems — Widely specified on chemical dosing lines handling chlorine, acid wash, and algaecide solutions where corrosion-resistant, cleanable valve internals are required
• Industrial & Process Piping — Throttling and shut-off on process lines carrying acids, bases, solvents, and industrial chemicals in manufacturing, pharmaceutical, and food processing environments where metal valves are unsuitable
• Slurry & Suspended Solids Service — The weir body design and flexible diaphragm make this valve uniquely capable in slurry lines, lime feed systems, and other applications with solids-laden fluids that would clog or abrade conventional valve types
• Irrigation & Fertigation Systems — Used on fertilizer injection lines and chemical feed points in commercial greenhouse and agricultural irrigation systems where precise flow control and chemical compatibility are both required
• Aquaculture & Water Features — Chemical resistance and clean shut-off make diaphragm valves a common specification in aquaculture recirculating systems, public aquariums, and water feature chemical treatment circuits
• Laboratory & Institutional Plumbing — Specified in lab drain systems, reagent supply lines, and process water circuits in educational, medical, and research facilities where chemical compatibility and precise flow control are priorities