MANUAL OF ZERO VELOCITY VALVES

1. Introduction

Scope

This manual provides guidelines for the installation, operation, maintenance, inspection, warranty coverage, and service procedures for Zero Velocity Valves used in water transmission, pumping stations, irrigation systems, and industrial pipelines.

Applications

Zero Velocity Valves are hydraulically operated non-slam check valves designed to close automatically when the forward flow velocity approaches zero, thereby preventing reverse flow and eliminating water hammer.

They are commonly used in:

• Pumping Stations
• Water Supply Networks
• Water Transmission Mains
• Irrigation Projects
• Water Treatment Plants
• Sewage Treatment Plants
• Industrial Process Pipelines
• Power Plant Cooling Water Systems

Purpose

The primary function of a Zero Velocity Valve is to:

• Prevent reverse flow.
• Eliminate water hammer.
• Protect pumps and motors.
• Reduce pressure surges.
• Improve system reliability and safety.

2. Installation Guidelines

Pre-Installation Inspection

Before installation:

• Verify valve size, pressure rating, and material specifications.
• Inspect the valve for transportation damage.
• Check hydraulic control components and tubing.
• Ensure the disc moves freely.

Pipeline Preparation

• Flush the pipeline thoroughly before installation.
• Remove welding slag, rust, debris, and foreign particles.
• Ensure proper pipeline alignment.
• Provide adequate pipeline supports.

Installation Position

• Install according to flow direction arrow marked on the valve body.
• Horizontal installation is generally recommended.
• Ensure sufficient space for maintenance and inspection.

Hydraulic Control System

Before commissioning:

• Verify all hydraulic control lines are properly connected.
• Check pilot valve settings.
• Ensure control chamber is free from air entrapment.

Installation Precautions

• Avoid excessive pipe stress on valve body.
• Install isolation valves where required.
• Ensure accessibility to hydraulic control components.

3. Operation Instructions

Normal Operation

During pump operation:

• Forward flow opens the valve.
• Hydraulic controls maintain stable operation.
• Flow passes with minimal head loss.

Automatic Closure

When the pump stops:

• Flow velocity decreases.
• Valve senses near-zero velocity condition.
• Disc closes before reverse flow develops.
• Water hammer is prevented.

Operating Advantages

• Non-slam operation.
• Elimination of reverse flow.
• Reduced pump damage.
• Improved pipeline protection.

Operating Precautions

• Do not manually interfere with hydraulic controls.
• Maintain operating pressure within rated limits.
• Avoid unauthorized adjustment of pilot settings.
• Ensure hydraulic tubing remains intact.

4. Maintenance Schedule

Monthly Inspection

• Check for external leakage.
• Verify hydraulic tubing condition.
• Inspect pressure gauges.
• Observe valve operation during pump start and stop cycles.

Quarterly Inspection

• Inspect pilot control valves.
• Check hydraulic oil or water control system.
• Examine fasteners and mounting components.
• Verify disc movement.

Annual Inspection

• Inspect valve internals.
• Examine disc and seat condition.
• Inspect hydraulic cylinder assembly.
• Check seals and gaskets.
• Test pilot valve functionality.
• Perform operational performance testing.

Recommended Spare Parts

• Hydraulic Cylinder Assembly
• Pilot Control Valve Kit
• Disc Assembly
• Seat Ring
• O-Rings
• Gaskets
• Pressure Gauges
• Hydraulic Tubing Components

5. Warranty Coverage

Warranty Exclusions

Warranty does not cover:

• Improper installation.
• Incorrect pilot valve settings.
• Damage due to contaminated fluid.
• Hydraulic control system tampering.
• Operation beyond rated pressure limits.
• Unauthorized modifications.
• Normal wear and tear.

6. Expected Service Life

Factors Affecting Service Life

• Pump Start/Stop Frequency
• Water Quality
• Pressure Fluctuations
• Hydraulic Control Maintenance
• Environmental Conditions
• Operating Pressure

Routine inspection and preventive maintenance significantly improve service life.

7. Customer Responsibilities

The customer shall:

• Ensure proper installation.
• Maintain hydraulic control systems.
• Conduct periodic inspections.
• Maintain operation and maintenance records.
• Operate within rated limits.
• Monitor pump shutdown performance.
• Report abnormalities promptly.

Failure to comply may affect warranty eligibility.

8. Warranty Claim Procedure

Step 1 – Claim Submission

Provide:

• Purchase Order Number
• Invoice Copy
• Valve Identification Details
• Installation Date
• Pump Details
• Operating Pressure Information
• Description of Defect
• Photographs of Installation

Step 2 – Technical Evaluation

The submitted information will be reviewed to determine:

• Installation compliance
• Hydraulic control condition
• Operating conditions
• Maintenance history
• Warranty applicability

Step 3 – Inspection

Where necessary:

• Site inspection may be conducted.
• Valve may be requested for detailed examination and testing.

Step 4 – Resolution

Based on technical findings, one of the following may be provided:

• Repair
• Component Replacement
• Hydraulic Control Adjustment
• Valve Replacement
• Technical Recommendations

Safety Precautions

• Depressurize the pipeline before maintenance.
• Never dismantle hydraulic components while pressurized.
• Wear appropriate PPE during servicing.
• Follow all site safety procedures.
• Ensure pumps are isolated before maintenance activities.

Document Retention

Maintain installation records, maintenance logs, pump operation records, inspection reports, hydraulic control settings, and warranty documentation throughout the service life of the valve for operational reference and warranty support.