DGL Boiler Feed Pump Minimum Circulation Flow Regulating Valve

DGL boiler feed pump minimum circulation flow control valve is a multi-stage throttling control valve for preventing cavitation, also called high pressure differential control valve, which is a control valve with novel structure and suitable for harsh working conditions. This valve is mainly used in the feed water system of large generator sets. It is an important equipment to prevent boiler feed pump vaporization and one of the key control valves in power plants.
DGL minimum flow control valve is a cascade structure, used for two-position switch action, and the fluid passes through a tortuous channel, the purpose is to consume fluid energy, reduce flow rate, and prevent liquid cavitation.

After the feed water pump is started, when the outlet valve has not yet started, or when the external load is greatly reduced (the unit is running at low load), the feed water flow rate is very small or zero. At this time, only a small amount of water or no water passes through the pump, and the friction heat generated by the impeller cannot be taken away by the feed water, causing the temperature in the pump to rise. When the temperature in the pump exceeds the saturation temperature under the pressure of the pump, the feed water will vaporize and form cavitation.
To prevent this phenomenon from happening, it is necessary to open this minimum flow regulating valve when the feed water flow of the feed water pump is reduced to a certain extent, so that part of the feed water returns to the deaerator, so that there is enough water in the pump to prevent the temperature from rising and vaporizing the feed water pump. This minimum flow rate is generally 25% to 30% of the rated flow rate of the feed water pump.

※ Structural Advantage
1. The fluid is depressurized step by step, and the direction of the fluid is constantly changing, which increases the flow resistance and prevents the fluid from cavitation when the high pressure difference occurs.
2. The valve core has five-level throttling, and a throttling element is set on the lower side of the valve seat sealing surface to improve the fluid flow state. The flow rate can be controlled at about 30m/s.
3. The throttling surface is separated from the sealing surface. The surface of the valve core, valve core sleeve and throttling part is nitrided and hardened. The hardness reaches about HRC70, which is tightly closed and has a long service life.
4. There is a large gap on the surface of the valve core. Even if the fluid contains solid particles such as 2-3mm welding slag, the valve core will not get stuck and the movement is flexible.

※ Technical Parameters
Valve body:
Type: Forged angle or "Z" type valve body
Nominal diameter: DN50-DN125
Nominal pressure: ANSI 1500, ANSI2500 or PN25, PN32MPa
Connection type: BW welding type (or as required by the user)
Material: 20# forging
Upper valve cover:
Normal temperature type ≤300℃
Remarks: The working temperature must not exceed the allowable range of various materials.
Gland type: Bolt clamping type
Packing: Graphite plus Inconel wire braided packing.
Valve components:
Valve core type: anti-cavitation cascade throttle valve core
Flow characteristics: two-position switch type
Media flow direction: high inlet and low outlet
Material: stainless steel nitriding hardening treatment
Performance:
Allowable pressure difference: 26MPa
Leakage: in accordance with ANSI B.16104-1976 IV level
Action time: less than ten seconds from fully closed to fully open
Actuator:
Equipped with electric actuator (electric open or electric close)
(Note: This valve can also be equipped with VP cylinder piston actuator)

※ Installation

※ Main Parts Materials
       

※ Kv Value and Stroke    

※ FAQ

What are the installation requirements for control valves?
The valve should be installed at the appropriate position of the pipeline to ensure that the flow direction is consistent with the direction indicated by the valve body; secondly, check whether the valve and its accessories are intact before installation to ensure that there is no damage; during installation, ensure that the pipeline connection is stable to avoid stress concentration and prevent damage to the valve; in addition, sufficient space should be provided for the valve to facilitate adjustment, inspection and maintenance; finally, the valve should be protected from excessive vibration or temperature, especially under high pressure and high temperature environments.

What are the common applications of temperature and pressure reducers?
Temperature and pressure reducers are widely used in many fields. They are mainly used in steam systems to reduce high-pressure steam to appropriate pressure to ensure safe operation of equipment. They are commonly used in power, fertilizer, food processing and other industries. They are also used in oil and gas pipelines, chemical production, pharmaceutical plants, etc. to ensure stable pipeline pressure and avoid system overpressure or excessive temperature. In addition, reducers are also used in HVAC, metallurgy and other industries to adjust the temperature and pressure of the fluid in the system to ensure the smooth progress of the process.

How to maintain medium and high pressure valves?
When maintaining medium and high pressure valves, first check the wear of key components such as valve body, valve seat, sealing ring and valve stem regularly. Clean the valve to prevent impurities from blocking and affecting operation. Check the operating performance of the valve to ensure flexible opening and closing without sticking. Check the sealing to prevent leakage and replace the seals if necessary. For valves that operate at high pressure for a long time, it is recommended to perform functional tests regularly to ensure their reliability under high pressure environment. In addition, check the connection parts of the valve to avoid looseness or leakage caused by vibration or corrosion.

※ Industry Applications

※ Company Introduction

Jiangsu Gaote Valve Industry Co., Ltd. was established in 2003. The company is a medium-sized enterprise specializing in the production of various petrochemical and power station valve series. The main products include high-temperature and high-pressure power station valves, gate valves, stop valves, ball valves, check valves, butterfly valves, instrument valves, needle valves, regulating valves and non-standard special valves for power stations, etc. Hundreds of varieties and specifications of valves, products are widely used in power, petrochemical, metallurgy, pharmaceutical, mining, steel, mining, water supply and drainage and other industries. The company's R&D team actively explores the field of valves and explores a path of industrial upgrading from ordinary valves to valves.

Jiangsu Gaote Valve Industry Co., Ltd. is an innovative demonstration enterprise of small and medium-sized enterprises in Jiangsu Province. It is located in the Economic Development Zone of Funing County, Jiangsu Province, and National Highway 204 passes through the territory. The company has passed the ISO9001 quality system certification and the special equipment manufacturing license of the People's Republic of China. It is a member unit of the power station accessories supply of the State Power Corporation, a member unit of the Sinopec Equipment Resources Market, and a member unit of the first-level supply network of China National Petroleum Corporation. It has gradually established a good reputation in power station valves. The company has an advanced management mechanism, with fixed assets of more than 30 million yuan, more than 100 sets of sophisticated mechanical processing equipment and inspection and testing equipment, and more than 10 technical R&D personnel, forming an integrated production, sales and service.