Gaoshan Valve — BQ340H Eccentric Semi-Ball Valve

Models: BQ340H-10C  /  BQ340H-16C  /  BQ340H-25  /  BQ340H-40  |  Pressure: PN10–PN40  |  Connection: Flanged  |  DN Range: DN50–DN1600  |  Type: Eccentric Semi-Ball Valve

Core Strengths

Product Overview

The BQ340H eccentric semi-ball valve is an advanced quarter-turn valve developed by Gaoshan Valve based on imported technology from similar valve designs, representing a new valve type optimized for flow control and isolation in pipelines carrying impurities, solid particles, grain materials, dregs, sewage, and other weakly corrosive fluids in petroleum, chemical, metallurgy, power generation, and water supply industries. The core innovation is an engineered axial eccentricity between the sealing disc and the valve spindle axis — when the disc rotates to close, it sweeps freely through the flow path without seating contact until the final moment of closure, at which point the eccentric geometry brings the disc firmly onto the seat with increasing sealing force proportional to line pressure. This mechanism eliminates the continuous surface rubbing that causes wear in conventional valves. Available in four pressure classes — PN10 (DN50–DN1600), PN16 (DN50–DN1000), PN25 (DN50–DN600), and PN40 (DN50–DN500) — with carbon steel bodies, stainless steel stems, and hard alloy sealing surfaces as standard. Three actuation modes (worm gear, electric, pneumatic) share identical valve body components. The pneumatic sealing test pressure is uniformly 0.6 MPa across all pressure classes. Temperature range extends from −29°C to +425°C. Face-to-face and flange connection dimensions comply with relevant GB standards.

Performance Specifications by Model

Materials of Main Parts

Main Dimensions — PN10 Series (DN50–DN1600)

* L = Face-to-Face Length; H1 = Height (closed); H2 = Overall Height (open, including actuator); A1 = Actuator width; A2 = Stem eccentricity offset; φ = Handwheel diameter. Note: PN16 / PN25 / PN40 series — dimensions for DN50–DN500 (PN16 up to DN1000) are the same as the corresponding PN10 sizes. Consult Gaoshan Valve for exact PN16/25/40 dimension sheets.

Structure Drawing

Design & Manufacturing Standards

• Design Standard: GB/T 12237 (Flanged Ball Valves) and equivalent eccentric semi-ball valve standards
• Face-to-Face Dimensions: GB/T 12221
• Flange Connection Standard: GB/T 9113
• Testing & Inspection: GB/T 13927
• Pneumatic Sealing Test: 0.6 MPa uniformly across all PN classes
• Carbon Steel Body Material: per GB/T standards for carbon steel castings
• Stainless Steel Stem: per GB/T standards for austenitic stainless steel
• Hard Alloy Sealing Surface: Stellite-equivalent overlay (wear & corrosion resistant)
• Actuator Mounting Interface: ISO 5211 (compatible with worm gear, electric, and pneumatic actuators)

Installation & Commissioning Guidelines

• Pre-Installation Pipeline Cleaning: Flush and clean all connected piping before valve installation. Even small abrasive particles left in the pipe can score the hard alloy seating surfaces during first operation. For slurry or particle service, install an upstream strainer for initial system commissioning — remove after the pipeline has been fully flushed and cleaned.
• Valve Orientation: The BQ340H may be installed with the spindle in any orientation (horizontal, vertical-up, vertical-down) without performance impact. However, for worm gear manual operation, ensure adequate clearance for the handwheel rotation arc. The H2 dimension (overall height including actuator) must be verified against available headroom before installation.
• Flange Connection: Align valve flanges concentrically with mating pipe flanges and insert all bolts before tightening. Tighten in a diametrically-opposite cross-pattern in three incremental passes to ensure even gasket compression and prevent body distortion. Use appropriate flange gaskets rated for the operating pressure class and temperature range. For PN25 and PN40 services, use spiral-wound metallic gaskets.
• Initial Stroke Verification: Before pressurizing the pipeline, manually operate the valve through at least two full open-close cycles to verify smooth disc rotation, correct end-stop positions, and absence of mechanical binding. Check that the position indicator (if fitted) correctly shows fully open and fully closed states. For electric or pneumatic actuated versions, conduct a dry-run stroke test to verify actuator response and limit switch calibration.
• Eccentricity Inspection: The eccentric geometry is factory-set and does not require field adjustment. Do not attempt to modify or adjust the eccentric offset. If the valve does not seat properly after installation, check that the valve body has not been mechanically stressed by misaligned flanges or improper bolt tightening — body distortion can interfere with the eccentric seating mechanism.
• Throttling Service: For throttling and flow control applications, avoid sustained partial-open positions near the fully-closed position (0°–15° opening) at high differential pressures. Near-closed throttling at high velocities creates erosive flow conditions that attack seating surfaces in any valve type. Preferred throttling range is 15%–80% open. Install a flow control valve downstream for precise low-flow regulation if required.
• Maintenance Schedule: Inspect packing gland for leakage every 12 months under normal service conditions. Retighten the packing follower if minor stem leakage appears — do not overtighten as this increases operating torque. Inspect the hard alloy seating surfaces during scheduled shutdowns for scoring or pitting; minor surface damage can be lapped smooth by qualified valve technicians. Replace packing every 3–5 years depending on service temperature and media conditions.
• Worm Gear Maintenance: Check and replenish worm gear grease every 24 months or after 500 operating cycles, whichever comes first. Use EP (extreme pressure) grease rated for the service temperature range. For outdoor or submerged installations, verify the worm gear housing seal integrity annually to prevent water ingress.

Application Fields