Pilot operated commander nitrogen seal valve pressure regulating valve

1、 Product Introduction:
ZZYVP-16BPilot operated commander nitrogen seal valveThe function of structural decomposition is to prevent volatile toxic or flammable gases from leaking out of the storage tank and endangering safety. A certain pressure of nitrogen is maintained inside the tank with a slight pressure, and the nitrogen sealing valve is located on the top of the tank. The medium at the pressure point is introduced into the detection mechanism through a pressure guiding pipe. The design of the feedback structure allows the medium to directly enter the detection mechanism through the valve cover. The tank breathing valve at the top of the tank can play a safety role. Generally, the pressure setting point of the nitrogen release valve is slightly higher than that of the nitrogen supply valve to avoid frequent operation of the nitrogen supply and release devices. In terms of flow control, each valve is equipped with a fixed plate hole to control the flow percentage. The size of each valve in the gas sealing system is arranged according to the gas flow meter, and the flow rate suitable for specific gas sealing needs is calculated based on the provided stable gas pressure The nitrogen gas in the nitrogen sealing valve can serve functions such as replacing the medium of the device and balancing the pressure of the system, used to maintain a constant pressure of the protective gas at the top of the container. The general nitrogen pressure is atmospheric pressure, mainly used to reduce volatilization, such as in benzene tanks, and to prevent the reaction between the medium and air, such as in alkali tanks. The pressure inside the tank is generally reduced to 1 bar. The gas seal protection system is suitable for various large storage tanks, operates reliably, and is widely used in industries such as petroleum and chemical.

The breathing valve should be installed at a high point of the gas source in the storage tank to reduce material evaporation loss and ensure a direct and large channel for tank breathing. For vertical tanks, the valve should usually be installed within the central top plate range of the tank top as much as possible. For storage tanks that require insulation layer on the tank top, it can be installed near the ladder platform. When two breathing valves need to be installed, they should be symmetrically arranged with the center of the tank top. If the breathing valve is used on a nitrogen sealed tank, the connection position of the nitrogen supply pipe should be far away from the valve interface and inserted into the storage tank from the top of the tank by about 200mm, so that nitrogen is not directly discharged after entering the tank, achieving the purpose of nitrogen sealing

2、 Working principle of nitrogen sealing:
ZZYVP-16B Pilot CommanderNitrogen sealing valveMainly used to cover the upper end of finished liquid in storage tanks with nitrogen gas (function: to prevent liquid products, volatile liquids, etc. in the tank from directly contacting the air, avoid volatilization, deterioration, and ensure quality), controlled by a nitrogen sealing device, which can easily achieve this function.
When the material outlet valve is opened to release liquid, the liquid level in the storage tank decreases, the volume of the gas phase increases, and the nitrogen pressure drops below the set value. At this time, the ZZVVP-16B nitrogen supply valve opens to supplement nitrogen into the tank, increasing the pressure inside the tank to the set value. The ZZVP-16K nitrogen supply valve automatically closes. Similarly, when the inlet valve is opened, the liquid level rises, the volume of the gas phase decreases, and the nitrogen pressure increases. If the pressure exceeds the set value, the nitrogen release valve automatically opens to release pressure until the pressure drops to the set value, and the nitrogen release valve automatically closes.
Advantages:
(1) The nitrogen supply pressure can be easily set without stopping production;
(2) Wide range of nitrogen pressure settings: from 0.35KPa to 10KPa
Valve setting parameters:
(1) ZZYVP-16B nitrogen supply valve front pressure 0.2-0.8MPa, nitrogen seal pressure 1KPa.
(2) The set pressure before the ZZVP-16K nitrogen relief valve is 2KPa.

(3) HXF-10 flame retardant breathing valve positive pressure+3Kpa, negative pressure -295Pa.

IIIOrdering Notice:

◇ Nitrogen supply valve, nitrogen release valve nominal diameter DN (mm)
◇ Media name
◇ Nitrogen supply and discharge device nominal pressure PN (MPa)
◇ Work pressure and adjustment range
◇ Rated flow coefficient Kv for nitrogen supply and discharge devices
Valve body, valve internals, and packing materials
◇ Inherent flow characteristics of nitrogen supply and discharge devices
◇ Device name and model
◇ Pressure setting points for nitrogen supply and release devices
4、 Product features:
◇ Using a commander for operation, the pressure reduction ratio can reach 100:1, with good pressure reduction effect and high control accuracy;
To ensure the safety of the storage tank, a breathing valve should be installed on the top of the tank;
The breathing valve only serves a safety purpose, avoiding the defect of frequent opening and closing and easy damage in conventional nitrogen sealing devices.
Without the need for external energy, it can work in situations without electricity or gas, which is both convenient and energy-saving, reducing costs;
The pressure setting is convenient and can be carried out under continuous production conditions;
The effective area of the force detection diaphragm is large, the set spring stiffness is small, the action is sensitive, and the device works smoothly;
Adopting a non packing design, the valve stem experiences low friction, responds quickly, and has high control accuracy;

5、 Precautions and daily maintenance for the installation of nitrogen sealed valves:
1. Installation precautions:

（1）nitrogen blanketingBefore installation, check whether the parts of the whole machine are damaged or loose, clean the pipelines, and ensure that the flow direction of the medium is in line with the arrow on the valve body.
(2) For the convenience of on-site maintenance and operation, there should be appropriate space around the valve.
(3) Valves should be installed upright and vertically on horizontal pipelines, with the valve body connected to the pipeline flange. Attention should be paid to the axial alignment, and they should be installed for use in environments where the ambient temperature does not exceed -25~55 ° C.
2. Use of nitrogen sealing valve
(1) Open the shut-off valve in front of the valve to allow the medium to slowly flow into the valve body
(2) Unscrew the commander cover and loosen the commander adjustment screw
(3) Adjust the main spring of the controller to bring the pressure behind the valve to the set value
(4) Fix the command device adjustment screw, install the protective cover, and the pressure regulating valve can start working
(5) When not in use, close the front shut-off valve of the valve
6、 Installation diagram:

7、 Main technical parameters and performance indicators:
Pressure regulation range Kpa 0.5~70 20~120 60~400 300~700 500~1000
Nominal pressure PN (Mpa) 1.0 1.6
Temperature of the regulated medium (℃) 80 200
Allowable pressure drop (Mpa) 1.6 1.6 1.1 0.6 0.4
Effective area of actuator film (C ㎡) 200 280 400
Allowable leakage rate: Complies with ANSI B16.104-1976 Class IV
Nominal diameter DN (mm) 20 25 40 50 80 100 150
Valve seat diameter DN (mm) 6 15 20 25 32 40 50 65 80 100 125 150
Rated flow coefficient Kv 3.2 5 8 10 20 32 50 80 100 160 250 400

8Case study on nitrogen sealing technology for storage tanks:

The nitrogen sealing system consisting of a nitrogen supply valve, a nitrogen release valve, and a breathing valve ensures that the top space of the storage tank is under inert air protection and atmospheric pressure control. Today, let's learn how to prevent air pollution from ultra pure water containers?

The air contains impurities such as carbon dioxide, bacteria, and dust, and ultrapure water is a pure solvent with strong solubility for these impurities. Therefore, once ultrapure water comes into contact with air, its electrical resistivity will rapidly decrease. Practice has shown that ultrapure water with a resistivity of 15M Ω· cm or more will drop to 3-4M Ω· cm after being exposed to air for 1 minute, and will drop to around 2M Ω· cm after 3 minutes. Therefore, it is necessary to reduce the chance of contact between ultrapure water and air.

How to prevent ultrapure water containers from being contaminated by air?There are many solutions, and the commonly used ones are the following three:

1. Nitrogen filling method: that is, filling nitrogen gas on the water surface of the water tank to maintain an appropriate positive pressure inside the tank, preventing the atmosphere from contacting the water surface inside the tank, which is not the nitrogen sealing protection system we often refer to.

2. Film bag method: a bag shaped film is placed inside the water tank to cover the water surface. The film bag rises and falls with the water level, reducing the contact area between the water surface and the air.

3. Floating roof method: A lightweight material with a density lighter than water is used to make a whole plate-shaped floating roof in the water tank and float it on the water surface. The gap between the floating roof and the box is covered with lightweight elastic materials (such as sponge, foam plastic, etc.), and the floating roof rises and falls with the water surface. Thereby reducing the chance of contact between air and water surface.