A  повеќестепена вертикална турбинска пумпа  is widely used in high-pressure, continuous-duty applications such as power plants, water treatment facilities, and industrial systems. To ensure long-term reliable operation, one critical component often overlooked is the minimum flow valve, also known as the automatic recirculation valve (ARV). This valve plays a vital role in protecting the pump from severe issues like overheating, cavitation, vibration, and system instability during low-flow operation.

This article explores the working principle, advantages, installation requirements, and maintenance tips for the minimum flow valve in a повеќестепена вертикална турбинска пумпа систем.

1. What Is a Minimum Flow Valve and How Does It Work?

The minimum flow valve is installed at the outlet of the multistage vertical turbine pump. It ensures that even during periods of reduced system demand, the pump maintains a minimum required flow rate to prevent internal overheating and damage.

The valve operates similarly to a check valve and adjusts based on the flow rate in the main pipeline:

When the main pipeline flow is above a set threshold, the bypass remains closed.

When flow drops below the minimum, the valve automatically opens a bypass line, redirecting flow back to the deaerator or reservoir, ensuring recirculation and pump protection.

This self-operating system uses internal mechanical levers and valve discs to sense changes in flow and automatically adjust the bypass accordingly.

2. Operation Process of the Minimum Flow Valve

Normal Flow Conditions:

When the system flow is normal, the main valve disc opens, and the mechanical lever closes the bypass. All flow is directed to the process line.

Low Flow Conditions:

As flow decreases, the main disc starts to close. Once it hits the threshold, it fully shuts the main passage and simultaneously opens the bypass. This allows liquid to recirculate from the pump discharge back to the pump suction or deaerator, preventing pump damage.

This ensures that the multistage vertical turbine pump is never starved of flow, even during startup, shutdown, or low-demand periods.

3. Key Advantages of Using a Minimum Flow Valve

The minimum flow valve integrates multiple protective and control functions into a single unit. Key benefits include:

Automatic self-regulation:Operates based on flow changes without external power or control signals.

Bypass flow control:Minimizes energy loss by avoiding continuous recirculation.

Check valve functionality:Both the main line and bypass include non-return capabilities.

Дизајн што заштедува простор:Three-way T-shaped body simplifies piping layout.

Енергетско ефикасно работење:No need for constant bypass flow, reducing system energy consumption.

Reduced system complexity:Combines multiple components into one, lowering design and procurement workload.

Пониски вкупни трошоци:Minimizes initial investment, installation, and long-term maintenance costs.

Подобрена сигурност:Reduces risk of cavitation and mechanical failures under low-flow conditions.

Pump protection under all flow conditions:Maintains safe operation for the multistage vertical turbine pump, even during abnormal flow.

Работа без одржување:Mechanical construction with minimal failure points and no external controls.

4. Упатства за инсталација

To ensure the minimum flow valve functions correctly:

локација:Install the valve as close as possible to the pump discharge—ideally within 1.5 meters—to reduce noise and water hammer risk.

Ориентација:Vertical installation (flow from bottom to top) is preferred, but horizontal installation is also possible.

Bypass direction:Ensure proper flow routing back to the deaerator, tank, or pump inlet for effective recirculation.

5. Препораки за одржување и нега

To prolong the life of the minimum flow valve and ensure reliable operation:

Начин на чување:Store in a dry, ventilated space; seal both ends to prevent debris intrusion.

Inspection before use: Verify the valve label, inspect the sealing surface and internal cavity for contamination.

Редовни проверки:After installation, periodically inspect the sealing surfaces and O-rings. Replace or repair worn components promptly.

чистење:Keep internal parts clean to avoid blockages or valve failure.

Заклучок

The minimum flow valve is an essential safeguard for any multistage vertical turbine pump operating under variable flow conditions. It automatically ensures minimum recirculation to prevent damage caused by cavitation, overheating, and dry running—problems that are especially common in high-pressure, critical systems. With its integrated functions, mechanical simplicity, and energy-saving design, the valve contributes to the reliable and cost-effective operation of vertical turbine pump systems.

For long-term system health and pump protection, incorporating a minimum flow valve is not just a recommendation—it's a necessity.