Model 300X

Coliter ® Slow Closing Check Valve – Hydraulic Automatic Control, PN1.0~2.5, Prevents Water Hammer in Pump Systems

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300X Slow Closing Check Valve – Pilot-Operated Hydraulic Check Valve with Needle Valve & Micro Filter for Silent, Controlled Closure

The Coliter® 300X Slow Closing Check Valve is an advanced hydraulic control valve designed to prevent backflow while eliminating water hammer through precisely controlled, slow-closing operation. Unlike conventional check valves that slam shut during pump shutdown, the 300X uses a hydraulic pilot system—comprising a main valve, internal check valve, needle valve, ball valve, micro filter, and pressure gauge—to regulate the drainage speed from the main valve control chamber. During normal flow, inlet water enters the control chamber via the micro filter and one-way valve, then slowly drains through the adjustable needle valve. Because the needle valve’s orifice is smaller than the ball valve’s, pressure in the control chamber drops, allowing upstream pressure to lift the main disc and open the valve. When flow stops (e.g., pump off), the control chamber drains at a controlled rate set by the needle valve, causing the main disc to close gradually—typically over 3–60 seconds—thereby preventing destructive pressure surges. Rated for PN1.0, PN1.6, or PN2.5 (1.0–2.5 MPa), it operates reliably at temperatures up to 80°C and is ideal for pump discharge lines in water supply, HVAC, fire protection, and municipal networks. Constructed from ductile iron or cast steel, with flanged ends per GB/T 17241.6 / ISO 7005, available in sizes from DN50 to DN800. Compliant with GB/T 12235 and API 598, the 300X delivers silent, maintenance-free, and system-protecting reverse-flow prevention without external power.

Installation diagram

Product Description

Type 300X slow-closing check valve consists of main valve, check valve, needle valve, ball valve, micro filter and pressure gauge to form a hydraulic control valve takeover system. Using hydraulic automatic operation, the main valve can get the best opening and closing speed. Prevent water hammer and water hammer, so as to achieve the effect of slow closing and silencing. When the water feeds water from the inlet end, the water enters the main valve control room through the micro filter, needle valve and one-way valve, and then drains to the downstream through the ball valve. Because the opening of the needle valve is smaller than the opening of the ball valve, that is, the drainage speed of the main valve control room is greater than the water inlet speed, so the pressure in the control room decreases, and the inlet pressure acting on the main end of the main valve disc opens the main valve to supply water downstream.

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Coliter®’s check valves prevent backflow and water hammer in pumping stations, HVAC systems, fire protection, and municipal water networks. The series includes the H44H cast steel swing check valve for high-pressure service, H41H cast steel lift check valve for vertical flow, H44W stainless steel swing type (304/316) for corrosive media, H44X (SFCV) rubber disc silent check valve for quiet operation, HC41X energy-saving silent check valve with spring-assisted closure, and HC42X/DRVZ slow-closing silent check valve to eliminate water hammer. Available in flanged or threaded connections (DN15–DN600), rated at PN10–PN40, and compliant with GB/T 12235 and API 598 standards—ensuring reliable, maintenance-free reverse-flow protection across diverse applications.