YJF or JZF Type High-Pressure Stop Valve

I. Product Introduction

The high-pressure stop valve is a forced-seal pipeline cut-off valve. The valve body opening/closing component has a plug-shaped structure with flat and cone seal types. The valve core moves in a straight reciprocating motion along the fluid centerline to complete pipeline on-off operations. This valve can be used in fully open and fully closed conditions, but cannot be used for medium regulation or pipeline throttling during operation; it is dedicated only for medium conduction and isolation. The valve is available in conventional forced-seal and new self-seal structures, suitable for high-pressure oil and gas, hydraulic, and chemical process pipeline applications, complying with domestic valve industry standardization construction specifications.

II. Valve Stem Motion Types

The valve stem has two motion structures for different control installation conditions:

1. Lifting stem type: Only the valve stem lifts and lowers; the handwheel does not move synchronously, with a simple control structure;

2. Lift-rotate stem type: The handwheel and valve stem rotate and lift synchronously; the valve body has a built-in fixed matching nut, providing stronger opening/closing control stability.

III. Conventional Forced-Seal Stop Valve Opening/Closing Force Principle

The high-pressure conventional model has a forced-seal structure. When the valve is closed and locked, external force must be applied to press the sealing contact surface to prevent medium leakage at the seal. When medium flows into the valve chamber from below the valve core, opening/closing operations must overcome dual resistance: the friction between the valve stem and packing, and the axial thrust generated by medium pressure.

Under this structural condition, the force required to close the valve is greater than that to open it, so the valve body is equipped with a larger diameter valve stem; if the stem is too small, it may bend and deform at the top after pressure overload, affecting normal valve opening/closing.

IV. Self-Seal Type High-Pressure Stop Valve Optimization Features

With valve body process iteration and upgrading, self-seal type stop valves have gradually become popular, optimizing the medium inflow direction so that medium enters the valve chamber from above the valve core. Relying on the medium own pressure to assist sealing, the force required to close the valve is greatly reduced, the opening force is relatively larger, the valve stem diameter can be reduced, and the overall valve body structure is lighter; at the same time, the medium self-presses the sealing surface, providing better closing seal fit and more stable anti-leakage sealing effect.

V. Industry Installation Flow Direction Standards

According to the three-standardization standards of the domestic valve industry, stop valves uniformly implement top-to-bottom medium flow direction installation standards. Construction and installation must follow the standard flow direction layout to ensure balanced valve body force and compliance sealing, avoiding opening/closing jamming and sealing failure caused by reverse installation.

VI. Structural Core Features

1. Plug-shaped valve core structure with flat and cone seal options, suitable for different high-pressure sealing conditions;

2. Two valve stem structures available, lifting and lift-rotate types, suitable for different manual opening/closing installation scenarios;

3. Limited operating conditions, can be fully opened and fully closed, prohibited for throttling and flow regulation;

4. Conventional forced-seal model with large closing load, thickened valve stem to prevent bending damage, suitable for high-pressure heavy-duty pipelines;

5. Self-seal model with optimized force, labor-saving opening/closing, smaller valve stem specification, medium-assisted sealing with excellent anti-leakage performance;

6. Standardized installation, unified top-to-bottom flow direction, suitable for industry project acceptance and pipeline maintenance standards.

VII. Core Applications

Widely used in high-pressure hydraulic pipelines, chemical high-pressure process pipelines, oil and gas transportation pipelines, and energy storage high-pressure oil circuits, exclusively for full open/close cut-off isolation of pipeline media, not suitable for flow regulation or throttle pressure regulation conditions, suitable for long-term high-pressure fluid on-off control.

VIII. Usage Precautions

1. Strictly follow the valve body flow direction identification, install from top to bottom, reverse installation is prohibited;

2. Use full open and full close positions; long-term operation in half-open state is prohibited to prevent erosion damage to the sealing surface;

3. For conventional forced-seal valves, apply closing pressure at uniform speed; do not violently turn the valve stem to prevent stem bending;

4. For high-pressure heavy-duty pipelines, prefer thickened valve stem forced-seal models; for reduced-load conditions, use self-seal models;

5. Regularly inject packing lubricant to reduce valve stem reciprocating opening/closing friction and reduce operating load;

6. During maintenance, check valve stem deformation; replace promptly if slight bending occurs to avoid high-pressure opening/closing jamming failure;

7. Distinguish between the two valve body structures, select as needed, do not mix installation standards to ensure normal sealing force.