How to choose the right inlet valve solenoid valve, solenoid valve type, maintenance, maintenance, repair

How to choose the right inlet valve solenoid valve, solenoid valve type, maintenance, maintenance, repair

Import valve valve is mainly refers to foreign brands, mainly Europe and the United States, the Japanese brands, more representative brands include Britain sent her, the force Germany LIT, Japan north jersey KITZ, the United States, a RETZ, such as valve type of products are mainly imported ball valves, import cut-off valve, import control valve, butterfly valve, import import pressure reducing valve, imported electromagnetic valve, etc., And the caliber of the product, pressure, temperature, material, connection mode, operation mode and other parameters are many, need to choose the right valve according to the actual needs, product characteristics; This article is combined with the German brand German Litt LIT, the analysis of the specific selection of imported valves:
A, the characteristics of the import valve use characteristics and structural characteristics
1, the use of imported valve characteristics
The use characteristics of the valve to determine the main performance and scope of use, belong to the valve use characteristics are: valve category (closed valve, regulating valve, safety valve, etc.); Product type (gate valve, globe valve, butterfly valve, ball valve, etc.); The material of the main parts of the valve (valve body, valve cover, stem, disc, sealing surface); Valve transmission mode, etc.
2. Structural characteristics
The structural characteristics of the valve installation, maintenance, maintenance and other methods of some structural characteristics, belonging to the structural characteristics are: the length and overall height of the valve structure, and the pipeline connection form (flange connection, thread connection, clamp connection, external thread connection, welding end connection, etc.); Sealing surface form (insert ring, thread ring, surfacing, spray welding, body body); Valve stem structure (rotating rod, lifting rod), etc.
Two, the selection of valve steps
Clarify the use of valves in equipment or devices, determine the working conditions of valves: applicable medium, working pressure, working temperature and so on; For example, if you want to choose a German LIT globe valve, confirm that the medium is steam, the working principle is 1.3Mpa, the operating temperature is 200¡æ.
Determine the nominal size and connection mode of the pipe connecting with the valve: flange, thread, welding, etc. For example, choose imported globe valve, confirm the connection is flange.
Determine the way to operate the valve: manual, electric, electromagnetic, pneumatic or hydraulic, electro-hydraulic linkage, etc. For example, the manual globe valve is selected.
According to the pipeline transmission medium, working pressure, working temperature to determine the selected valve shell and inner parts of the material: cast steel, carbon steel, stainless steel, alloy steel, rust acid steel, gray cast iron, malleable cast iron, ductile iron, copper alloy, etc.; For example, the cast steel material chosen for the globe valve.
Choose the type of valve: closed valve, regulating valve, safety valve, etc.
Determine the type of valve: gate valve, globe valve, ball valve, butterfly valve, throttle valve, safety valve, pressure reducing valve, steam trap, etc.
Determine the parameters of the valve: for automatic valves, according to different needs to determine the allowable flow resistance, discharge capacity, back pressure, etc., and then determine the nominal diameter of the pipeline and the diameter of the seat hole;
Determine the selected valve geometry parameters: structural length, flange connection form and size, open and close after the height direction of the valve size, the size and number of bolt holes connected, the size of the whole valve shape;
Use the available information: valve catalogue, valve product samples, etc., to select the appropriate valve products.
Three, the basis of valve selection
The use of the selected valve, operating conditions and control mode;
The nature of the working medium: working pressure, working temperature, corrosion performance, whether it contains solid particles, whether the medium is toxic, whether it is flammable, explosive medium, medium viscosity, etc.; For example, want to choose Germany LIT imported solenoid valve, medium and environment flammable, explosive, generally choose explosion-proof solenoid valve; For example, to choose Germany LIT ball valve, the medium contains solid particles, generally choose v-type hard sealing ball valve.
Requirements for valve fluid characteristics: flow resistance, discharge capacity, flow characteristics, sealing grade, etc.;
Installation size and external size requirements: nominal diameter, connection mode and connection size with pipes, external size or weight limit, etc.
Reliability of valve products, explosion-proof electric device performance and service life of the additional requirements (when the selected parameters should be paid attention to: if the valve is used for control purposes, must determine the following additional parameters, operation methods, big and small flow, normal flow pressure drop, the closing pressure drop, large and small valve inlet pressure).
According to the above valve selection basis and steps, a reasonable and correct choice of valves must also be detailed understanding of the internal structure of various types of valves, so as to make the right choice of the preferred valve.
The final control of the pipe is the valve. The valve opening and closing parts control the flow mode of medium in the pipeline. The shape of the valve flow channel makes the valve have certain flow characteristics, which must be taken into account when choosing the valve suitable for installation in the pipeline system.
Summarize, the selection of several major elements: determine what function of the valve to choose, confirm the temperature and pressure of the medium, confirm the flow of the valve and the caliber needed, confirm the valve material, operation mode;

Solenoid valve, solenoid valve type, maintenance, maintenance, repair
I. Applicability
The fluid in the pipeline must be consistent with the calibrated medium in the solenoid valve series.
The temperature of the fluid must be less than the calibration temperature of the solenoid valve. Solenoid valve allowed liquid viscosity is generally below 20CST, greater than 20CST should be indicated. Working pressure difference, pipeline maximum pressure difference in less than 0.04mpa should be used such as ZS,2W,ZQDF,ZCM series and other direct moving type and step by step direct moving type; The lowest working pressure difference is greater than 0.04mpa, can choose the pilot type (differential pressure) solenoid valve; The maximum working pressure difference should be less than the maximum calibration pressure of the solenoid valve; General solenoid valve is one-way work, so pay attention to whether there is a backpressure difference, such as the installation of check valve.
Fluid cleanliness is not high should be installed in front of the solenoid valve filter, liquid gas solenoid valve for media cleanliness is better. Pay attention to flow aperture and pipe diameter; Solenoid valve generally only switch two control; If conditions permit, please install bypass pipe for easy maintenance. Water hammer phenomenon to customize the solenoid valve opening and closing time regulation. Pay attention to the influence of ambient temperature on the solenoid valve: The power supply current and power consumption should be selected according to the output capacity, the power supply voltage is generally allowed to ¡À10%, must pay attention to the HIGH VA value when ac starting.
Ii. Reliability
Solenoid valve is divided into normally closed and normally open two kinds; Generally choose normally closed type, power on open, power off; But in the open time is very long closed very short to choose normally open type.
Life test, the factory generally belongs to the type test project, to be exact, there is no professional standard of solenoid valve in Our country, so choose solenoid valve manufacturers carefully.
When the action time is very short and the frequency is high, the direct action type is generally selected, and the fast series of large diameter is selected.
Three, security
General solenoid valve is not waterproof, please choose waterproof when conditions do not allow, the factory can be customized. The maximum nominal pressure of the solenoid valve must exceed the maximum pressure in the pipeline, otherwise the service life will be shortened or other unexpected circumstances. All stainless steel should be used for corrosive liquid, and plastic King (SLF) solenoid valve should be used for strong corrosive fluid. The corresponding explosion-proof products must be selected for the sexual environment.
Iv. Economy
There are a lot of solenoid valves can be general, but on the basis of meeting the above three points should choose the most economical products.
The structure principle of solenoid valve
A, direct acting solenoid valve
There are normally closed and normally open two types. Normally closed type power is closed state, when the coil is energized when the electromagnetic force, so that the moving iron core overcome the spring force with the static iron core suction directly open the valve, the medium is a path; When the coil power off when the electromagnetic force disappears, the moving iron core under the action of the spring force reset, directly close the valve port, the medium is not. Simple structure, reliable action, zero differential pressure and micro vacuum under normal operation. Normally open is just the opposite. Such as less than ¦Õ6 flow diameter solenoid valve.
Two, step by step direct acting solenoid valve
The valve uses a valve and two open valve connected in one, the main valve and guide valve step by step electromagnetic force and pressure difference directly open the main valve port. When energized coil, thus moving iron core and static iron core and electromagnetic force, pilot valve is located in the main valve and pilot valve mouth mouth open mouth, and the moving core and the main valve core together, at this time the main valve cavity pressure on the unloading, through the pilot valve port under the action of pressure difference and the electromagnetic force at the same time the main valve core upward movement, open the main valve medium circulation. When the coil power when the electromagnetic force disappears, the moving iron core in the dead weight and spring force under the action of closing the pilot valve hole, at this time the medium in the balance hole into the main spool cavity, the upper chamber pressure, at this time in the spring return and pressure to close the main valve, the medium flow. Reasonable structure, reliable action, and reliable operation at zero differential pressure. For example: ZQDF, ZS, 2W, etc.
Three, indirect pilot solenoid valve
The series solenoid valve is composed of pilot valve and main spool to form a channel combination; Normally closed type is closed when no power is energized. When the coil is energized, the magnetic force generated so that the moving iron core and static iron core pull, pilot valve opening, media flow to the outlet, at this time the main spore cavity pressure reduction, lower than the inlet side of the pressure, the formation of differential pressure to overcome the spring resistance and then upward movement, to open the main valve port purpose, medium flow. When the coil power, the magnetic force disappears, the moving iron core under the action of the spring force reset close pilot port, at this time the medium from the balance hole into the main spool chamber pressure increases, and under the action of the spring force downward movement, close the main valve port. The normally open formula works just the opposite. Such as: SLA, DF (¦Õ15 caliber above), ZCZ and so on.