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

The closure member of a gate valve is a gate, which moves perpendicular to the fluid flow. A stem gate valve is designed solely for full open or full close operation, not for regulation or throttling. The gate typically has two sealing faces forming a wedge; the wedge angle varies with parameters, commonly 23°, suitable for media temperatures up to 80°C when not elevated, as seen in common configurations like the 8 flanged gate valve. Wedge gates can be rigid (one-piece) or flexible (able to deform slightly to compensate for machining deviations and improve sealing).

When closed, sealing can rely on medium pressure alone pressing the gate against the seat (self-sealing), though many gate valves use forced sealing (external force applied to ensure seal). In a non rising sluice valve, the stem does not rise externally; the stem nut is on the gate inside the body. Rotating the handwheel turns the stem, which engages the nut to raise or lower the gate. The full-open position is determined by gate travel; it cannot be monitored visually by stem height.

Product Core Parameters

Nominal Diameter: DN50-DN1200
Nominal Pressure: PN10, PN16, PN25
Operating Temperature: 0～80°C
Applicable Medium: Water

Installation Diagram

Product Application

The non rising sluice valve (a specific example of which is the 8 flanged gate valve) uses a wedge gate structure where the rubber-coated gate provides deformation compensation for effective sealing. The stem nut inside the body contacts the medium directly. Rotating the stem drives the nut to move the gate vertically for opening/closing. It is widely used in construction, petroleum, chemical, food, pharmaceutical, textile, power, shipbuilding, metallurgy, and other industrial pipeline systems as a shut-off device.

Maintenance & Installation Notes

The handwheel, handle, or transmission mechanism must not be used for lifting, and impact is prohibited.

Prefer horizontal installation with stem vertical and handwheel on top. It can be mounted in any orientation, but the stem should be horizontal. Horizontal gate valves install only on horizontal pipes with stem horizontal and handwheel upward.

Installation must ensure accessibility for operation, maintenance, and replacement.

The valve must be operated fully open or fully closed. Do not use it partially open for flow control, as high fluid velocity can damage sealing surfaces.

Operate by rotating the handwheel; do not use auxiliary levers.

For valves with a bypass, open the bypass first to balance pressure difference across the valve and reduce opening force.

For valves with actuators, follow the manufacturer's instructions for installation.

If frequently operated, lubricate moving parts regularly. Apply grease to stem trapezoidal threads for smooth operation and corrosion protection, at least monthly.

During installation:

9.1 Clean internal cavity and sealing surfaces; no dirt should adhere.

9.2 Check that connecting bolts are evenly tightened.

9.3 Ensure packing is properly compressed - it should seal effectively without hindering stem rotation.

Post-installation periodic checks:

10.1 Wear condition of sealing surfaces.

10.2 Wear of stem and stem nut threads.

10.3 Wear of guide rails inside body and gate guide slots.

10.4 Whether packing is worn out.

10.5 Verify packing integrity (repeated for emphasis per original text).

After assembly/repair, conduct a sealing performance test. Record all maintenance details for future reference.

Common Failures & Solutions

Common Failure	Causes	Remedies
Body & Cover Leakage	Freezing cracks (in cold climates)	Insulate or heat-trace valves for temperatures at/below 0°C. Drain water from valves taken out of service.
Body & Cover Leakage	Damage from heavy object impact	Do not stack heavy items on valves. Avoid hammer strikes. Provide supports for large-diameter valves during installation.
Sealing Surface Leakage	Incomplete closure or fine gaps formed after closure due to thermal contraction, leading to erosion.	Operate strictly per indicated direction. For high-temperature valves, close once, wait, then close again to compensate for thermal contraction.
	Excessive closing force applied beyond full closure (e.g., using long levers incorrectly), crushing/deforming sealing surfaces.	Follow proper operating procedures for valve opening/closing.
	Excessive wear of sealing surfaces causing misalignment ("wire drawing") and poor contact.	Adjust sealing surfaces if misaligned; replace if adjustment is not possible.

FAQ

Q: What is the primary space-saving benefit of a non rising sluice valve compared to a rising stem type?

A: The stem gate valve with a non-rising stem does not require additional vertical clearance for the stem to extend, making it advantageous for installations in confined spaces or underground pipelines.

Q: How is the full-open position determined for a 8 flanged gate valve if the stem doesn't rise visibly?

A: The full-open position is determined by the gate's internal travel limit. Operators typically rely on the handwheel's rotation count or torque feel, and it is crucial to follow manufacturer specifications to avoid over-torquing and damaging internal threads.

Q: Can a stem gate valve be installed with the stem pointing downwards?

A: While some designs allow multiple orientations, it is generally recommended to install with the stem horizontal or vertical (handwheel up) to prevent debris accumulation on the stem nut and ensure proper lubrication drainage, extending the valve's service life.

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