Tiansu (Tianjin) Valve Group Co., Ltd. is one of the leading manufacturers and suppliers of rising stem gate valve in China. If you're going to buy wholesale customized rising stem gate valve made in China, welcome to get quotation from our factory. Quality products and reasonable price are available.

A flanged rising stem gate valve serves as a key shut-off device in industrial pipelines. It is manufactured in various specifications, a common example being the 4 flanged gate valve configuration. Its rising stem design is a core feature: the stem and gate move together vertically. When open, the stem extends upward outside the valve cover; when closed, it retracts. The exposed stem length allows clear visual indication of valve position without disassembly. The threaded portion of the stem remains external (above the packing box or cover), avoiding direct contact with the medium, which prevents corrosion and debris jamming, extends thread life, and enables easy wear inspection. It employs a wedge-type single gate that forms line or surface contact with the seat. Upon closing, mechanical force combined with medium pressure creates a "self-sealing effect," enhancing sealing reliability under high pressure and making it suitable for conditions with significant fluctuations.

Product Core Parameters

Nominal Diameter: DN50-DN1400
Nominal Pressure: PN10, PN16, PN25
Operating Temperature: 0～80℃
Applicable Medium: Water

Product Application

The flanged rising stem gate valve, also called a rising stem sluice valve, is used for fully open or fully closed control in pipeline systems. Through the engagement of the trapezoidal thread on the stem top with a nut, rotary motion is converted into linear motion to drive the gate up or down, achieving fluid flow control. It is widely used in water supply, firefighting, and sewage systems. Common specifications are often identified by associated flange features, the 4 flanged gate valve (typically for sizes up to DN15-DN50) being a prevalent and standard type in many applications.

Daily Inspection (Daily/Weekly, Adjusted Per Service Frequency)

1. Visual & Status Check

1.1 Check valve body, flange faces, and packing box for leaks (internal leaks judged by pressure drop; external leaks observed directly).

1.2 Inspect exposed stem threads for rust or wear; apply anti-rust grease (e.g., graphite grease) to external threads to prevent oxidation.

1.3 Ensure valve position matches onsite indicators; check handwheel/actuator for looseness or damage; verify power indicator on electric actuators.

2. Operational Flexibility Check

2.1 Manually operate manual valves weekly (to prevent stem seizing); test electric valves remotely/on-site periodically.

2.2 If stem movement is stiff, do not force operation; investigate causes (e.g., debris, thread corrosion, over-tightened packing).

Regular Maintenance (Monthly/Quarterly/Annually, Based on Service Intensity)

Interval	Maintenance Items	Key Points
Monthly	Packing maintenance: Check seal condition. For minor leakage, evenly tighten packing gland bolts. If packing is aged (hardened/cracked), replace promptly.	When replacing, select material suitable for service (e.g., graphite for high temp, PTFE for corrosive media). Wrap evenly, avoid overlapping.
Quarterly	Stem lubrication: Clean exposed stem threads and guide bushings; apply dedicated grease (e.g., molybdenum disulfide for high temp, lithium-based for normal).	Remove debris/rust from threads before greasing. Apply evenly; avoid excess to prevent dust accumulation.
Semi-annually	Flange connection check: Re-tighten flange bolts if loose (cross-tighten). Check gasket seal; replace if leakage traces are found.	Prevent bolt corrosion; apply anti-rust oil on bolt heads for outdoor valves.
Annually	Complete overhaul: Disassemble cover; inspect gate and seat sealing surfaces for wear. Polish minor scratches/corrosion (manual paste or machine). Check stem nut/guide bushing wear; replace if needed.	Clean all parts after disassembly. Ensure gate aligns with seat upon reassembly; verify smooth stem movement; tighten bolts to specified torque.

Basic Operational Requirements

1. Operating Procedures

Manual operation: Turn handwheel slowly; avoid excessive force (especially for large diameters) to prevent thread damage or gate impacting seat. When fully open, leave 1-2 handwheel turns as margin (to avoid stem jamming). When fully closed, do not over-tighten (stop when leak-free; over-tightening may deform sealing surfaces).

2. Prohibited Operations

Do NOT use for flow regulation:

Partial opening causes high-velocity erosion of sealing surfaces, leading to wear, vibration, and eventual internal leakage.

Do NOT disassemble under pressure:

Never remove flange bolts, cover, or packing gland while valve is pressurized to avoid fluid ejection injuries.

Do NOT exceed rated conditions:

Do not surpass pressure / temperature limits on nameplate (e.g., a PN16 flanged gate valve must not be used in PN25 service).

Common Failures & Solutions

Common Failure

Causes

Remedies

Stem Movement Stiffness

1. Debris blocking gate in pipeline;

2. Stem thread corrosion, insufficient lubrication;

3. Packing too tight;

4. Gate and seat misaligned/wear.

1. Close upstream/downstream isolation valves, remove valve to clean debris;

2. Clean threads and apply lubricant;

3. Loosen packing gland appropriately;

4. Polish sealing surfaces and realign gate.

Packing Box Leakage

1. Packing aged/worn;

2. Uneven tightening of packing gland bolts;

3. Stem surface scratched.

1. Replace with suitable packing;

2. Tighten gland bolts evenly;

3. Repair stem scratches (minor scratches can be polished).

Body/Flange External Leak

1. Flange sealing surface contaminated/scratched;

2. Uneven bolt tightening;

3. Gasket damaged or material mismatch.

1. Clean sealing surface, polish scratches;

2. Tighten bolts crosswise evenly;

3. Replace with suitable gasket.

Internal Leakage

1. Gate/seat sealing surface worn/scratched;

2. Wedge angle deformed;

3. Valve not fully closed.

1. Polish sealing surfaces; replace gate/seat if severely worn;

2. Correct gate wedge angle;

3. Adjust to ensure full closure.

FAQ

Q: What is the main advantage of the rising stem design in a flanged rising stem gate valve?

A: The rising stem provides clear visual indication of valve position (open/closed) without needing to disassemble or rely on external indicators, enhancing operational safety and maintenance efficiency.

Q: Can a flanged gate valve be used for throttling or flow control?

A: No. This valve type is designed only for fully open or fully closed service. Using it for partial flow regulation leads to high-velocity erosion of the sealing surfaces, causing premature wear, vibration, and internal leakage.

Q: What does the "4" signify in a 4 flanged gate valve model designation?

A: In common valve model coding systems (e.g., Chinese standards), the numeral "4" often indicates a flanged gate valve connection type. It specifies the valve's end connection as flanged, as opposed to threaded, welded, or other types.

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