電磁閥原理、操作和應(yīng)用介紹（中英文）
一、什么是電磁閥？ / What are Solenoid Valves?
電磁閥是一種開/關(guān)機(jī)電操作閥，由電磁執(zhí)行器（螺線管）和閥體組成。螺線管柱塞組件是負(fù)責(zé)打開和關(guān)閉閥門的閥門執(zhí)行器。該致動器可以以柱塞動作只能打開或關(guān)閉的方式布置。沒有中間或中間位置，因此螺線管無法節(jié)流。閥體由與過程流體接觸的承壓部件組成。
螺線管將電能轉(zhuǎn)換為機(jī)械拉/推動作。它由緊緊纏繞在鐵芯上的線圈和鐵磁插頭或柱塞組成。組件因設(shè)計(jì)而異。當(dāng)電流通過線圈時，會產(chǎn)生磁場。磁力線可以想象成一系列以電流軸為方向的圓圈。如果電流沿環(huán)狀線圈流動，則圓圈組合形成如下所示的磁場。
A solenoid valve is an on/off electromechanically operated valve which consists of an electromagnetic actuator (solenoid) and a valve body. The solenoid-plunger assembly is the valve actuator responsible for opening and closing the valve. This actuator can be arranged in such a way that the plunger action can either open or close only. There is no intermediate, or in-between position, so there is no way for a solenoid to throttle flow. The valve body consists of the pressure containing parts in-contact with the process fluid.
The solenoid converts electrical energy into a mechanical pull/push action. This consists of a coil of wire tightly wrapped around an iron core, and a ferromagnetic plug or plunger. Components vary depending on the design. As an electrical current passes through the coil, a magnetic field is generated. The magnetic field lines can be imagined as a series of circles with the direction of its current axis. In the case of a flowing current along a looped coil, the circles combine forming the magnetic field shown below.
添加更多回路將增加磁力線或磁通量。這增加了螺線管的電磁力，這也意味著更多的力來驅(qū)動閥門。
另一種增加吸引力的方法是增加流過線圈的電流量。這是通過增加進(jìn)入螺線管的電源電壓來完成的。電磁閥可以使用直流或交流操作。常見的直流電壓有6、12、24和240伏；而 60Hz 的交流電是 24、120、240 和 480 伏。
Adding more loops will increase the amount of magnetic field lines or flux. This increases the electromagnetic force of the solenoid, which also means more force for actuating the valve.
Another way to increase the force of attraction is to increase the amount of current flowing through the coil. This is done by increasing the supply voltage into the solenoid. Solenoids valves can operate with either DC or AC. Common DC voltages are 6, 12, 24 and 240 volts; while AC at 60Hz are 24, 120, 240 and 480 volts.
比例電磁閥 / Proportional solenoid valves
比例電磁閥是一種特殊類型的電磁閥，可根據(jù)電輸入提供平穩(wěn)連續(xù)的流量或壓力變化。這種類型可歸類為控制閥。電磁閥要成為比例閥，必須控制柱塞位置。它是通過通常由彈簧產(chǎn)生的外力平衡柱塞來實(shí)現(xiàn)的。彈簧將壓縮直到外力等于螺線管的電磁力。如果必須控制柱塞的位置，則必須改變電流，從而導(dǎo)致彈簧上的力不平衡。彈簧將壓縮或拉伸，直到建立力平衡。
這種類型的一個問題是摩擦的影響。摩擦?xí)茐碾姶帕蛷椈闪Φ钠椒€(wěn)平衡。為了抵消這種影響，使用了特殊的電子控制。用于電磁閥比例控制特性的常用方法是脈寬調(diào)制或PWM。將 PWM 信號用作控制輸入會導(dǎo)致螺線管以非?？斓乃俣冗B續(xù)通電和斷電。這使柱塞處于振蕩狀態(tài)，從而使柱塞處于穩(wěn)定位置。以改變柱塞的位置。螺線管的開和關(guān)狀態(tài)（也稱為占空比）受到控制。
與普通的開/關(guān)電磁閥不同，比例電磁閥用于需要自動流量控制的應(yīng)用，例如比例氣動執(zhí)行器、節(jié)流閥、燃燒器控制等。
Proportional solenoid valves are a special type of solenoid valve that provides a smooth and continuous variation in flow or pressure in response to the electrical input. This type can be classified as a control valve. For a solenoid valve to become a proportional valve, the plunger position must be controlled. It is achieved by balancing the plunger through an external force usually done by a spring. The spring will compress until the external force is equal to the electromagnetic force of the solenoid. If the position of the plunger must be controlled, the current must be changed resulting in an imbalanced force on the spring. The spring will compress or stretch until force balance is established.
One problem with this type is the effects of friction. Friction disrupts the smooth balancing of the electromagnetic and spring forces. To negate this effect, special electronic control is used. Common method used to solenoid valves proportional control characteristics is pulse width modulation or PWM. Applying PWM signal as the control input causes the solenoid to energize and de-energize successively at a very fast rate. This puts the plunger in oscillation which nets into a stable position. In order to change the position of the plunger. The on and off states of the solenoid, also termed duty cycle, are controlled.
Unlike ordinary on/off solenoid valves, proportional solenoid valves are used in applications where automated flow control is required such as proportional pneumatic actuators, throttle valves, burner controls, and so forth.
二、電磁閥組件 / Solenoid Valve Components
如前所述，電磁閥可分為兩個主要部分：電磁閥和閥體。螺線管只是手動、氣動、液壓等多種執(zhí)行器中的一種。根據(jù)所需的動作類型，螺線管具有不同的部件。另一方面，每個閥門的閥體部件大致相同，但設(shè)計(jì)和材料不同。下面列出的是一般的電磁閥和閥體組件。
A solenoid valve, as mentioned earlier, can be separated into two major parts: the solenoid and the valve body. The solenoid is just one type in a variety of actuators such as manual, pneumatic, hydraulic and so forth. The solenoids have varying parts depending on the type of action required. The valve body components, on the other hand, are the same for every valve but with different designs and materials. Listed below are the general solenoid and valve body components.
三、電磁閥操作類型 / Types of Solenoid Valve Operations
電磁閥是根據(jù)它們的驅(qū)動模式、流路的數(shù)量和方向來描述的。按前者分別有直動式、內(nèi)部先導(dǎo)式和外部先導(dǎo)式。
Solenoid valves are described according to their mode of actuation, and number and direction of flow paths. This chapter discusses the former, namely direct-acting, internally piloted and externally piloted.
直動式 / Direct-acting
對于這種類型的電磁閥，靜壓力會隨著孔口尺寸的增加而增加。靜壓的增加需要更強(qiáng)的電磁鐵動作；因此，更強(qiáng)的磁場。這意味著對于給定的流體壓力，更大的流量需要更大的螺線管。流體壓力和流量然后與所需的螺線管尺寸成正比。這種類型的電磁閥通常用于流量和操作壓力較小的應(yīng)用。
With this type of solenoid valve, the static pressure forces increase as the orifice size increases. The increase in static pressure requires a stronger solenoid action; thus, a stronger magnetic field. This means for a given fluid pressure, larger flow rates require larger solenoids. The fluid pressure and flow rate then becomes directly proportional to the required size of the solenoid. This type of solenoid valve is usually used for applications with small flow rates and operating pressures.
內(nèi)部先導(dǎo) / Internally Piloted
對于高流量和高壓應(yīng)用，使用內(nèi)部先導(dǎo)電磁閥。在這種類型的閥門中，通過閥門的壓力打開或關(guān)閉閥門。為此，安裝了一個節(jié)流孔或一個平衡孔。通常的設(shè)計(jì)涉及孔口上的核心阻塞流。當(dāng)閥門關(guān)閉時，流體通過孔口，壓力在隔膜兩側(cè)增加。只要流體流動受阻，由于隔膜頂部的有效面積較大，就會產(chǎn)生關(guān)閉力。當(dāng)閥門打開時，核心打開孔口，壓力從隔膜頂部釋放。然后管線壓力打開閥門。
For high flow rate and high pressure applications, internally piloted solenoid valves are used. In this type of valve, pressure across the valve opens or closes the valve. To achieve this, an orifice or an equalizing hole is installed. The usual design involves the core blocking flow on the orifice. When the valve is closed, the fluid passes through the orifice and pressure builds up on both sides of the diaphragm. As long as fluid flow is blocked, a shut-off force is created due to the larger effective area on top of the diaphragm. When the valve is opened, the core opens the orifice and pressure is relieved from the top of the diaphragm. The line pressure then opens the valve.
外部先導(dǎo) / Externally Piloted
這種類型的閥門采用與內(nèi)部先導(dǎo)閥相同的概念，但用于驅(qū)動閥門的壓力來自外部源的流體。一個單獨(dú)的流體回路通過一個額外的端口集成到閥門中。
內(nèi)先導(dǎo)式和外先導(dǎo)式電磁閥均稱為間接或伺服輔助閥，其主要驅(qū)動力來自于閥門上游和下游之間的壓差。
This type of valve applies the same concept from internally piloted valves, but the pressure used to actuate the valve comes from a fluid from an external source. A separate fluid circuit is integrated to the valve through an extra port.
Both the internal and external piloted solenoid valves are called indirect or servo-assisted valves where the main actuating force comes for the differential pressure between upstream and downstream of the valve.
半直接作用 / Semi-direct Acting
半直動式結(jié)合了直接作用閥和間接作用閥的原理。除了來自螺線管的磁力外，閥門兩端的壓差有助于打開或關(guān)閉閥門。當(dāng)柱塞被驅(qū)動時，隔膜被提升以打開閥門。同時，一個孔口打開，導(dǎo)致隔膜頂部的壓力釋放。通過柱塞關(guān)閉該孔口會在關(guān)閉閥門的隔膜頂部產(chǎn)生更大的壓力。
Semi-direct acting combines the principles of direct and indirect acting valves. Aside from the magnetic force from the solenoid, pressure differential across the valve assists in opening or closing the valve. When the plunger is actuated, the diaphragm is lifted to open the valve. At the same time, an orifice is opened causing pressure to be relieved on top of the diaphragm. Closing this orifice by the plunger creates a larger pressure on top of the diaphragm closing the valve.
四、不同的電磁閥電路功能 / Different Solenoid Valve Circuit Functions
電磁閥的特點(diǎn)還在于其流路或電路功能。電磁閥可以打開、關(guān)閉、分配或混合此類別的流體。要更好地了解電磁閥電路功能，首先必須看一下標(biāo)準(zhǔn)化的電磁閥符號。
ISO，或國際標(biāo)準(zhǔn)化組織，是標(biāo)準(zhǔn)化機(jī)構(gòu)的全球聯(lián)合會。他們與 IEC（國際電工委員會）合作，制定了符號標(biāo)準(zhǔn)和規(guī)則，用于設(shè)計(jì)用于元件和電路圖中的流體動力符號。該標(biāo)準(zhǔn)為 ISO 1219。
Solenoid valves are also characterized by its flow path or circuit function. Solenoid valves can open, close, distribute or mix fluids as expressed by this category. To better understand solenoid circuit functions, one must first take a look at the standardized solenoid valve symbols.
ISO, or the International Organization for Standardization, is a worldwide federation of standardization bodies. In collaboration with the IEC (International Electrotechnical Commission), they created a standard of symbols and rules for devising fluid power symbols for use on components and in circuit diagrams. This standard is ISO 1219.
在上面的符號中，綠色框表示閥門的位置數(shù)。另一方面，箭頭指示流動方向。藍(lán)色箭頭表示加壓流動，而紅色表示排氣。紫色的 T 線是關(guān)閉的端口。
In the symbol above, the green boxes represent the number of positions of the valve. The arrows, on the other hand, indicates the direction of flow. The blue arrow means pressurized flow, while the red means exhaust. The purple T-lines are the closed ports.
以下是按電路功能分類的常見電磁閥類型。
The following are the common types of solenoid valves according to circuit function.
二通電磁閥 / Two-way Solenoid Valves
這種類型的電磁閥有一個上游端口和一個下游端口，用于阻止或允許流體流動。電磁閥可配置為常開和常閉；正常狀態(tài)是指斷電狀態(tài)。常開閥在斷電時打開，在通電時關(guān)閉。常閉閥則相反。
This type of solenoid valve has one upstream and one downstream port and is used to block or allow fluid flow. The solenoid valve can be configured as normally open and normally closed; normal state means the de-energized state. A normally open valve opens when de-energized and closes when energized. The opposite is true for normally closed valves.
三通電磁閥 / Three-way Solenoid Valves
三通電磁閥有三個端口：入口（壓力端口）、排氣和出口（執(zhí)行器端口）。這些用于交替地從執(zhí)行器或下游設(shè)備施加和排出壓力。三通電磁閥也可配置為常開和常閉，增加了通用功能。對于常開型三通閥，當(dāng)閥門斷電時，流體從入口流向出口，而排氣口關(guān)閉。通電時，進(jìn)氣口關(guān)閉，出氣口與排氣口相連。常閉閥則相反。另一方面，通用功能用于選擇從一個端口到另一個端口的流向。
Three-way solenoid valves have three ports: inlet (pressure port), exhaust and outlet (actuator port). These are used to alternately apply and exhaust pressure from an actuator or downstream equipment. Three-way solenoid valves can also be configured as normally open and normally closed, with the addition of a universal function. For a normally open three-way valve, when the valve is de-energized, fluid flows from the inlet port to the outlet port, while the exhaust port is closed. When energized, the inlet port is closed, and the outlet port connects to the exhaust port. The opposite is true for normally closed valves. The universal function, on the other hand, is used for selecting the direction of flow from one port to another.
四通電磁閥 / Four-way Solenoid Valves
四通電磁閥有四個端口：入口（壓力端口）、兩個出口或執(zhí)行器端口和一個排氣端口。有些設(shè)計(jì)有兩個排氣口。在這種類型的配置中，沒有常開或常閉。流量要么流向第一個出口端口，要么流向第二個出口端口。
Four-way solenoid valves have four ports: inlet (pressure port), two outlet or actuator ports, and an exhaust port. Some designs have two exhaust ports. In this type of configuration, there is no normally open or close. Flow either goes to the first outlet port or to the second.
請注意，這些類型的閥門，無論是二通閥、三通閥還是四通閥，都可以是直接或間接作用的。
Note that these types of valves, either two-, three- or four-way valves, may either be direct or indirect acting.
五、常見應(yīng)用 / Common Applications
使用電磁閥的主要優(yōu)點(diǎn)是其外形緊湊且易于控制。幾乎所有需要遠(yuǎn)程控制的行業(yè)都使用電磁閥。
The main advantage of using solenoid valves is its compact profile and ease of control. Almost all industries that require remote control use solenoid valves.
氣動和液壓回路 / Pneumatic and Hydraulic Circuits
電磁閥用于停止或允許沿回路供應(yīng)空氣或液體（通常是油或制冷劑）。此類別下的常見應(yīng)用是制冷、空氣壓縮和潤滑系統(tǒng)。制冷劑回路的示例如下所示。
Solenoid valves are used to stop or allow supply of air or liquid (usually oil or refrigerant) along a circuit. Common applications under this category are refrigeration, air compression and lubrication systems. An example of a refrigerant circuit can be seen below.
自動化 / Automation
每當(dāng)必須自動控制流體流動時，都會使用電磁閥，例如在機(jī)器人技術(shù)或工廠自動化中。這些電磁閥由具有一組編碼動作的微控制器或可編程邏輯電路控制。這種對流體流動的控制允許機(jī)器人精確、準(zhǔn)確地執(zhí)行定義的動作序列。
Solenoid valves are used whenever fluid flow must be controlled automatically, such as in robotics or factory automation. These solenoid valves are controlled by microcontrollers or programmable logic circuits with a coded set of actions. This control of fluid flow allows a defined sequence of actions to be executed precisely and accurately by a robot.
工業(yè)和制造工廠閥門執(zhí)行器 / Industrial and Manufacturing Plant Valve Actuators
對于電磁閥不能處理的流體，通常使用氣動、液壓和電機(jī)執(zhí)行器。然而，由于使用螺線管易于控制，電磁閥被集成到氣動和液壓閥執(zhí)行器中。工廠中的控制閥通常由電磁閥控制的壓縮空氣系統(tǒng)驅(qū)動。
For fluids that cannot be handled by solenoid valves, pneumatic, hydraulic and motor actuators are commonly used. However, due to the ease of control using solenoids, solenoid valves are integrated into pneumatic and hydraulic valves actuators. Control valves in industrial plants are usually actuated by a compressed air system controlled by solenoid valves.
醫(yī)療、制藥和食品制造 / Medical, Pharmaceutical and Food Manufacturing
電磁閥在醫(yī)療設(shè)備中的常見用途是用于透析機(jī)、麻醉機(jī)和呼吸機(jī)系統(tǒng)的定制閥門。制藥和食品加工使用符合衛(wèi)生要求的電磁閥。
Common uses of solenoid valves in medical equipment are custom valves for dialysis machines, anesthesia machines and ventilator systems. Pharmaceuticals and food processing use solenoid valves complying with hygienic requirements.
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