Hydraulic cartridge valve was born in the 20th century 50’s, growth in the seventies of the 20th century, and gradually developed into a covered direction control system, pressure control, flow control, almost all kinds of valve, with the ratio control proportional pressure valve, flow control valve, proportional control valve, the formation of an independent system. The machine has the advantages of small size, compact structure, small internal leakage, flexible application, low cost, simple installation and maintenance, etc., and is widely used in engineering machinery.
Hydraulic cartridge valve has a series of advantages due its characteristics , which have been widely used in agricultural machinery, waste treatment equipment, cranes, demolition equipment, drilling equipment, forklifts, road construction equipment, fire engines, and forestry machinery in Europe and America. Road sweeper, Excavator, Utility vehicle, Steamer, Manipulator and oil well, Mine, Metal cutting, Metal forming machinery and equipment, Plastic machinery and equipment, Forming machinery and equipment, Paper machinery and equipment, Textile machinery and equipment, Packaging, etc. Equipment and power unit, hydraulic or machinery test systems, etc.
This article briefly introduces the application of screw thread cartridge valve in construction machinery.
A. Hydraulic Cartridge Valves:
Hydraulic screw in cartridge valve is screwed into the cartridge valve, its installation is in a socket using screw is screwed into the valve block, assembly and disassembly is simple and high-efficient, general is composed of a valve sleeve, a valve core, a valve body, a sealing component, control components (spring seat, a spring, a regulating screw, a magnetic body, an electromagnetic coil, an elastic pad). Generally speaking, the valve sleeve and the valve core and the valve body are screwed into the valve block, and the rest of the valve body is outside the valve block.
Specifications have two, three, four, and other cartridge valve, the path from 3 mm to 32 mm, the maximum pressure of up to 63MPa, maximum flow rate of 760L/min. Directional valve, one-way valve, a hydraulic control one-way valve, shuttle valve, hydraulic pneumatic valve, manual valve, solenoid valve, electromagnetic valve, pressure valve is a relief valve, pressure relief valve, sequence valve, balance valve, pressure differential relief valve and load sensing valve etc.; flow valve throttle valve, control valve, shunt collecting valve, priority valve and so on.
Application of hydraulic screw threaded cartridge valve in construction machinery:
B. Cartridge Valve Applications:
1.Cartridge Valve In Application Of Hydraulic Pump
The earliest cartridge valves are used in the hydraulic pump. Because the hydraulic pump needs to be integrated hydraulic valve, which requires a small hydraulic valve, so as to develop a threaded cartridge type relief valve. It should be said that the cartridge relief valve is the earliest development, the application of the earliest threaded cartridge valve, and then there are threaded cartridge valve, screw-in cartridge type throttle valve and other applications in the hydraulic pump.
Modern hydraulic pump has a number of cartridge valves integrated, there are more than a dozen threaded cartridge valve integrated. Cartridge type overflow valve for regulating the main hydraulic pump and oil supply pump maximum pressure; cartridge type one-way valve for control circuit open or cut off; cartridge style globe valves are used in the event of a system failure is communicated to a, B port, convenient mechanical engineering or drag traction; threads in mounted pressure differential relief valve for regulating the output pressure of the pump changes with the change of load pressure. With screw in valve technology continues to progress, the development of the special multifunctional valve for pump, integrated the thread cartridge type overflow valve, threaded cartridge pressure differential relief valve, screw in type one-way valve are installed, in thread mounted valve, etc. four valve function.
2.Cartridge Valve In Application Of Hydraulic Motor
Cartridge valves are often used in hydraulic motors, especially for closed motors. Screw-in cartridge type overflow valve is used to regulate the oil pressure of the system; hydraulic cartridge shuttle valve for the high pressure side of the pressure oil into P solenoid directional control valve port; hydraulic cartridge type electromagnetic direction control valve is used to control the motor displacement, in thread mounted three three-way shuttle valve, also called thread cartridge type hot oil shuttle valve, then in the closed loop type motor at both ends. System is reverse run to ensure that the high pressure side has a certain amount of oil back to the fuel tank, in order to achieve a closed circuit cooling.
3. Application In Multi-Way Directional Valve
In the multi way reversing valve in addition to the valve, the integration of the safety valve, hydraulic check valve, overload valve, oil supply valve, shunt valve, brake valve, load sensitive valve, etc..
In the LS of cartridge type overflow valve for regulating valve maximum output pressure; cartridge type two-way load sensitive valve role in reversing valve core an opening, can guarantee the port A or B to the mouth of the output flow rate is a constant value, the mechanism of running speed without load, threaded cartridge shuttle valve is used to obtain the maximum load pressure and introduced into the variable pump, the pump output flow with the load pressure changes and changes in thread mounted oil feeding check valve to prevent hydraulic cylinder or motor suction, cartridge type balance valve is used to eliminate peak pressure, make the system have negative load running smoothly. In the end plate integrated with cartridge valve, cartridge type overflow valve, threaded cartridge valve is decompression of the high-pressure oil used as proportional solenoid pilot oil source and prevent damage to the high-pressure proportional electromagnet, screw in type overflow valve is used to regulate the pressure of the proportional electromagnetic iron pilot oil source is arranged.
4.Cartridge Valve In Application Of Sandwich Valves And Modular Valves
In construction machinery, also often used by the screw-in cartridge valve and the composition of the valve. Sandwich valve composed of a two position two-way valve can by balancing valve, relief valve, electromagnetic valve, solenoid valve, a one-way valve, a liquid control one-way valve, throttle valve, one-way throttle valve, control valve, shuttle valve, cut-off valve, a priority valve combination, can be a two-way valve, a three-way valve, can also be to four-way valve; can be made into a superposition valve, can also be made into a modular valve; can be made into six sizes can also be made ten path. Superposition valve generally by the combination of two valve, also can by a valve and a plugging head combination and become, modular valve general only one valve, using very flexible, can achieve nearly a hundred kinds of function, can solve many practical problems.
5.Cartridge Valve In Control Circuit
In the engineering machinery, screw thread cartridge valve is mostly used in the control loop. With the development of a variety of functional circuits, threaded cartridge valve group has been widely used in construction machinery.
6. Application In The Two Way Cartridge Valve
In the engineering machinery hydraulic system often use two way cartridge valve, two way cartridge valve cover plate in the pilot control valve is a lot of thread plug valve.
In two-way cartridge valve cover plate mainly used the thread cartridge valve is a one-way valve, a hydraulic control one-way valve, relief valve, pressure reducing valve, electromagnetic valve, solenoid valve, throttle valve, a one-way throttle valve, shuttle valve. If you do further development can also have more threaded cartridge valve can be applied to the two way cartridge valve cover plate, 16mm through the diameter of the following two cartridge valve assembly, can be made into the form of threaded cartridge, domestic and international has such a mature product, the flow rate of about 200L/min, so that the application of threaded cartridge valve has been extended.
C. Hydraulic Cartridge Valve Uses With Caution:
When using hydraulic screw cartridge valve, should pay attention to the following matters:
(1) In the use of screw-in cartridge valve, be sure to confirm the flow and pressure, but also pay attention to the flow pressure curve, if the selection is too small tend to cause the system pressure loss is too large, so that the heating system, if the selection is too large, resulting in economic waste.
(2) There are two kinds of threaded, cartridge valves sealing materials, the FPM rubber seal is suitable for the phosphate medium, NBR rubber seal is suitable for mineral oil medium.
(3) For the cartridge valve pressure and flow value can specify the set value, if not specified in the selection, the manufacturer will set a default value.
(4) Cartridge valve is more afraid of pollution, in the design of the system must do a good job in the design of the filter, and before the operation to fully clean up.
(5) The reverse speed of the screw insertion type solenoid directional valve is slightly slower than that of the conventional solenoid valve. For the occasion of the request for fast action, only select the fast type screw plug type solenoid valve, but the price is higher;
(6) The size and working pace of the restrictions, the cartridge valve performance is less than the traditional valve, such as the relief valve hysteresis, shunt valve flow accuracy, flow valve dynamic response performance, etc.
(7) With respect to the modular type valve block and the two-way cartridge valve block, the design of hydraulic cartridge valve block is more difficult, it is best to use professional design software to design, and use a professional calibration software to check the valve block;
(8) The design of the cartridge valve block should be asked to plug the hole in the valve block on the side of the injection of the valve on the side of the model, in order to prevent the installation of wrong;
(9) Due to the construction machinery and other mobile devices on the weight of strict requirements, the valve block is generally used aluminum alloy forging.