Gaoshan Valve — PQ41F-16Q Draining Ball Valve

Models: PQ41F-16Q  |  Pressure: PN16 (1.6 MPa)  |  Connection: Flanged  |  DN Range: DN40–DN50  |  Type: Draining Ball Valve, Manual Lever Operated

Core Strengths

Product Overview

The PQ41F-16Q draining ball valve is a specialized quarter-turn shut-off valve designed for reliable drainage and blowdown operations in water, steam, oil, and non-corrosive fluid pipeline systems operating at temperatures up to 200°C. Featuring a compact one-piece body with a straight-through flow bore, the PQ41F-16Q allows rapid and complete evacuation of pipeline sections during maintenance, system shutdown, or blowdown procedures. The valve is constructed with a QT450-10 ductile iron body and bonnet, a 2Cr13 stainless steel ball and stem, and PTFE soft seat rings, delivering dependable sealing performance at the PN16 (1.6 MPa) pressure class. Available in DN40 and DN50 sizes with standard flanged end connections conforming to GB/T 9113, this valve is the ideal choice for boiler blowdown lines, pipeline drain points, tank emptying connections, and process system purge points where complete fluid evacuation is required. All valves undergo shell testing at 2.4 MPa and seal testing at 1.8 MPa per GB/T 13927 standards.

Performance Specifications

Materials of Main Parts

Main Dimensions & Connection Sizes

* L = Face-to-Face Length, D = Flange Outer Diameter, D1 = Bolt Circle Diameter, D2 = Raised Face Diameter, b = Flange Thickness, f = Raised Face Height, n-φL = Number & Diameter of Bolt Holes. All dimensions per GB/T 9113 PN16 flange standard.

Structure Drawing

Design & Manufacturing Standards

• Design Standard: GB/T 12237 (Ball Valves)
• Face-to-Face Dimensions: GB/T 12221
• Flange Standards: GB/T 9113 (PN16)
• Testing & Inspection: GB/T 13927
• Ductile Iron Material: QT450-10 per GB/T 1348
• Applicable International Standards: API 6D, BS 5351 (optional)

Installation & Maintenance Guidelines

• Pipeline Preparation: Ensure pipeline ends are clean, free of welding slag, scale, and foreign debris before installation. Flush the pipeline thoroughly to remove any particles that could damage the PTFE seats during initial operation. Use proper gaskets matching the flange face type (RF).
• Installation Position: The PQ41F-16Q draining ball valve should be installed at the lowest point of the pipeline section or vessel to be drained. For horizontal pipelines, install with the valve body bore in the same horizontal plane as the pipe centerline. For vertical drain lines, ensure the valve discharges downward to allow gravity-assisted drainage.
• Flow Direction: Install the valve so that the flow arrow cast on the valve body points toward the drain outlet. While the ball valve is bidirectional, correct orientation ensures optimal drainage performance and prevents debris accumulation in the valve cavity.
• Flange Bolt Tightening: Align flange faces evenly before tightening bolts. Follow a cross-pattern tightening sequence in multiple passes to achieve uniform gasket compression. Do not fully tighten one side first as this causes body distortion and ball binding. Refer to bolt torque tables for the specific bolt grade and gasket material.
• Operating Instructions: Fully open or close the valve only — never use a ball valve for intermediate throttling as partially exposed seats will erode quickly from high-velocity flow. When opening for drainage, pause briefly at mid-position (45°) to equalize pressure across the ball before completing the turn. Always close slowly after drainage is complete.
• Packing Maintenance: Periodically check the stem packing area for signs of weeping or external leakage. If minor leakage occurs, gently retighten the packing gland nut by no more than 1/6 turn at a time while cycling the handle. Over-tightening will score the stem and increase operating torque. Replace packing rings if leakage persists.
• Seat Inspection: PTFE seats are subject to wear and cold-flow over extended service life, especially in high-cycle draining applications. Inspect seats annually for deformation, scratches, or compression set. Replace seat rings if the valve fails to hold seal test pressure. Always replace both upstream and downstream seats together.
• Drain Port Protection: When the valve is in the closed position for extended periods, ensure the downstream drain port is protected from debris ingress. Install a protective cap or short spool piece when the drain connection is not in use to prevent foreign material from entering the valve cavity.

Application Fields