Selection of multi-stage CNC valves for chemical loading

Product name and model: FBDF type piston-type electro-hydraulic valve. Product name: Piston-type electro-hydraulic valve. Introduction to the piston-type electro-hydraulic valve: Yonglong Valves is a domestic enterprise specialized in the development and production of various multi-functional CNC electro-hydraulic valves. It possesses a computer-based testing system for evaluating the comprehensive properties of these valves, which enables it to ensure that the repeatability error for each valve is no more than 1 liter per batch shipped. The system also allows for supplementary oil filling (for example, 1 liter of oil can be added to each 4-inch electro-hydraulic valve), thus ensuring consistency during stepless opening and closing operations. Product name: FBDF, abbreviation: DYF. Multifunctional electro-hydraulic valves useful in the oil, chemical, and natural gas liquefied gas industries. Classified by application, they include: normal-temperature valves, low-temperature valves, gas valves, water valves, diaphragm electro-hydraulic valves, needle-type electro-hydraulic valves, and piston-type electro-hydraulic valves. The FBDF type piston-series CNC electro-hydraulic valve is a valve that is controlled by an electromagnetic pilot valve, with the pressure of the medium itself driving the main valve piston to move to any desired position. Controlled through specialized computer software, it enables automatic control over the flow rate, velocity, and pressure of the conveyed medium, and features functions such as constant flow, constant pressure, and elimination of water hammer. It is a new type of numerically controlled electro-hydraulic automatic control valve developed on the basis of diaphragm-type electro-hydraulic valves. The valve body can be made of cast aluminum, cast steel, fully stainless steel, etc., offering a wide range of applications. The reliability and controllability of this product are superior to those of diaphragm-type electro-hydraulic valves. Working principle of the piston-type electro-hydraulic valve: The FBDF series of piston-type CNC electro-hydraulic valves consists of six valves in total, namely one normally open solenoid valve, one normally closed solenoid valve, three 3/8” manual ball valves (needle valves), and the main valve (piston cut-off valve) (as shown in the figure). The normally open solenoid valve is installed on the upstream pipeline of the control circuit, while the normally closed solenoid valve is installed on the downstream pipeline of the control circuit. During the transportation of media through pipelines, when it is necessary to open a valve, a signal to open the valve is sent by the computer; the normally open solenoid valve is energized (thus closing), while the normally closed solenoid valve is energized (thus opening). At this point, the passage from the upstream side to the upper chamber of the main valve piston is blocked, while the passage from the upper chamber of the main valve piston to the downstream side is opened. At this point, the pressure of the medium at the lower part of the piston is higher than that at the upper part; the medium in the upper chamber of the main valve piston is discharged into the downstream pipeline through the channel of the normally closed solenoid valve, and the main valve opens. When it is necessary to close the valve, the computer sends a signal to close the valve; the normally open solenoid valve loses power and thus closes, while the normally closed solenoid valve also loses power and thus closes as well. At this point, the passage from the upstream side to the upper chamber of the main valve piston becomes open, while the passage from the upper chamber of the main valve piston to the downstream side is closed. The high-pressure medium from upstream enters the upper chamber of the main valve piston through the normally open solenoid valve. At this point, the pressures on the upper and lower sides of the piston are equal, and the spring force causes the main valve to close. During the opening and closing of the main valve, the normally open solenoid valve is energized (closed), while the normally closed solenoid valve is de-energized (closed). At this point, both the upstream and downstream channels are in a closed state; the medium pressure is trapped in the upper chamber of the main valve piston, locking the main valve in a fixed open position and thus maintaining a constant flow rate of the medium at the main valve outlet. When the upstream flow rate changes, the microcomputer sends signals to the corresponding solenoid valves based on the feedback from the flow meter, thereby allowing automatic adjustment back to the preset flow rate value. The control circuit of the FBDF series of digital control electro-hydraulic valves is also equipped with two manual ball valves that serve as response valves for the main valve. The one located in the upstream control circuit is used to close the control valve, while the one in the downstream control circuit is used to open it. By adjusting the opening degree of these two small valves according to the viscosity of the medium and the actual pipeline pressure, it is possible to fine-tune the opening and closing of the main valve (closure level: not more than 3/4) ； To more effectively eliminate water hammer in pipelines. The FBDF series of CNC electro-hydraulic valves are equipped with a ball valve in the downstream control circuit as a manual control valve; when power is lost or the solenoid valve fails to function, manually operating this valve allows the main valve to be opened or closed. It can also be used to check whether the piston of the main valve is working properly or is damaged. Valve body material: Cast steel, all-stainless steel. Media used: Light oil, lubricating oil, liquefied gas, benzene, alcohols, acrylonitrile and other chemicals. Common applications: Oils, ethanol mixtures, automotive applications, chemical industries, various types of gas valves

Regularly clean the filter in the fuel inlet line.