(Check valve or check valve)
Function: Only allows the oil to flow forward, and no reverse flow is allowed.
Classification: straight-through type, right-angle type
Structure: valve body, valve core cone, steel ball type, spring, etc.
Working principle: liquid flow from When the oil inlet flows in, A → B
When the liquid flows in from the oil outlet, A → B
Opening pressure: 0, 04——0, 1MPa
Back pressure valve: Pk=0.2——0.6 MPa 3 Function: forward flow, reverse controlled flow structure: ordinary one-way valve + hydraulic control device
K does not pass pressure oil, A → B
Working principle<
K pressure oil, A → B
Structural features: B→ A, ∵ PB=P, very high< /p>
∴ The back pressure of the spring chamber is very large, and the valve core can only be opened when pk is very large, which affects reliability.
So the following measures can be taken
1) Use the pilot valve to relieve pressure in advance
2) Use the external drain port to return oil to reduce the back pressure
< p>Application: ∵ Hydraulic control check valve has good back sealing performance∴ Commonly used in pressure maintaining, locking and balancing circuits which are equivalent to a combination of two check valves
With logic OR gate function. It is widely used in logic loops and program control loops, and is commonly used in the conversion of manual to automatic loops.
Because the shuttle valve has a passage process during the reversing process, when the air intake or exhaust volume of a certain interface is very small, the pressure before and after the valve cannot be generated to make the valve reversal normally. The valve cannot completely change direction and stops midway, causing the valve to malfunction. Therefore, please be careful not to use a reducing joint at a certain interface to cause the passage to be too small. Function: It is to speed up the movement of the cylinder for rapid exhaust.
Cylinder disinfection under given conditions depends largely on the size of the control valve. If the speed needs to be increased (especially when the one-way speed needs to be increased), a quick exhaust valve can be installed. without having to bear the cost of a large control valve. (1) The structure and working principle of the reversing valve
Valve body: cylindrical hole with multi-stage undercut grooves
Structure<
Valve core: Yes Cylinder with multi-section circular groove
Classification:
Two positions
According to the number of working positions< Three positions: the working position of the valve core relative to the valve body number.
Four-position
Two-way is divided according to the number of channels< Three-way: the number of main oil ports connected to the outside of the valve body
Four-way (excluding control oil and leakage Oil port)
Five-way
Electromagnetic reversing valve
Hydraulic reversing valve
According to control method Motorized reversing valve The meaning of the graphic symbols of manual reversing valve: 1 position - represented by a square grid, the number of digits equals several squares 2 Pass - ↑ No pass - ┴, ┬ The number of intersections between the beginning and end of the arrow and the interception symbol and a square is the number of passes. 3 The oil port has a fixed orientation and meaning, p——oil inlet (lower left), T——oil return port (lower right), A.B——and actuator Connected working oil ports (upper left and right). 4 Spring - W, M, drawn on both sides of the square Two-position valve, one square against the spring. 5 Normal position 〈 In the schematic diagram, the oil line should be connected to the normal position: three-position valve, one space in the middle. Middle position function of the slide valve Slide valve function: When the reversing valve is in the normal position, the connection mode of each oil port in the valve, for the three-position valve, that is, the middle position of each /p> The way the oil port is connected, so it is called the median function. Neutral position function: When the three-position directional valve is in the neutral position, the connection method of each oil port in the valve. (3) Main performance of reversing valve 1) Reliable operation 2) Small pressure loss 3) Internal leakage Small 4) Reversing time and reset time 5) Long service life (4) Operating mode characteristics: Use manual lever to control the movement of the valve core to Control flow direction Classification: steel ball positioning type, spring return type. Multi-channel reversing valve Features: It is a centralized arrangement of combined manual reversing valves Series type Classification : According to the combination method, there are Sequential single-acting characteristics: Use a stopper or cam to move the valve core to control the flow direction Classification: Usually a two-position valve, there are two Two-way, three-way, four-way Example: two-way motorized reversing valve Composition: valve body, valve core, spring, roller, etc. Working principle< Roller pressure: P→ A Features: Use the thrust of the electromagnet to push the movement of the valve core to control the flow direction. Two-way and four-way Category: two-position four-way and five-way Example: three Four-way electromagnetic directional valve: Composition: valve body, valve core, spring, electromagnet, etc. Working principle: The positions shown in the figure, P, A, B, and T are all No connection The right electromagnet is energized, P → A, B → T The left electromagnet is energized, P → B, A → T Two-position three-way Electromagnetic reversing valve: Working principle: Pictured position, P → A B ┴ Electromagnet is energized, P → B A ┴ Symbol: AC (D) Electromagnet classification: According to the power source This type of dry type According to whether there is oil inside Liquid< Wet type has long service life. Features: Use pressure oil to change the position of the slide valve to control the flow direction Classification: two-position, three-position, etc. Composition: Working principle: The position shown in the picture, p, A, B, all → T X1 passes pressure oil, p → A, B → T X2 passes pressure oil, p → B, A → T Features: Use solenoid valve to control hydraulic valve to change the direction of liquid flow. Solenoid valve (pilot valve) Composed of 〈 〉 Hydraulic valve (main valve) Working principle: Electricity: p ┴ A, B → T Illustration< Liquid: p, A, B, and T are all blocked Electricity: p → A → left chamber of hydraulic valve, right chamber of hydraulic valve → B → T 1YA is powered on< Liquid: p → A, B → T Electricity: p → B → right chamber of hydraulic valve, left chamber of hydraulic valve → A → T 2YA is powered on< Liquid: p → B, A → T Features: (1) The damping regulator (also known as the reversing time regulator) is actually a stacked one-way throttle valve that can be stacked between the pilot valve and the main valve. (2) Main valve core stroke adjustment mechanism (3) Preload valve - often installed in the electro-hydraulic directional valve with internal control for oil supply. 3 Ball valve type directional valve Features: The ball valve type directional valve is a form of seat valve type directional valve, which changes the flow direction by changing the relative position of the steel ball in the valve body. Self-operated pressure regulating valve Self-operated pressure regulating valve does not require other external energy sources such as power and air sources, and is driven only by the energy of the medium itself. It is both energy-saving and environmentally friendly. It is easy to use. After installation, the pressure value is set and it can be put into automatic operation. Therefore, it is increasingly used in situations where control accuracy is not high and there is a lack of power and air sources. Such control valves are all included in Kuaiyou. However, during use, you must pay attention to the particularity of model selection, otherwise it may easily cause accidents. During use, attention should be paid to the selection and installation environment. Therefore, it is very important to understand the working principle and structure of the self-operated pressure regulating valve in detail. Use and scope of application Self-operated pressure regulating valve (hereinafter referred to as pressure valve) is an energy-saving device that does not require external energy and only relies on the pressure change of the medium itself to automatically adjust the pressure. Type product. It has comprehensive functions of measurement, execution and control. It is widely used in petroleum, chemical industry, metallurgy, light industry and other industrial sectors as well as urban heating and air supply systems. This product can be used as a pressure control device for non-corrosive (maximum temperature 350°C) liquids, gases, steam and other media.