Solenoid valf, elektromanyetik kontrol ile kontrol edilen bir tür endüstriyel ekipman olup, endüstriyel kontrol sistemindeki ortamın yönünü, akışını, hızını ve diğer parametrelerini ayarlar. Solenoid valfın yapı prensibi, sınıflandırılması, özellikleri, seçimi, bakımı, hataları ve çözümleri esas olarak tartışılmaktadır.

1. Structural principle of solenoid valve

(1. Valve body 2. Air inlet 3. Air outlet 4. Conductor 5.Plunger)
When the solenoid valve is not set on, the valve needle blocks the passage of valve body under the action of spring, and solenoid valve is in the cut-off state. When the coil is powered on, the coil generates a magnetic force. The valve core is lifted up against the spring force, the channel in valve is opened, and the solenoid valve is in a conducting state.

 

2. Solenoid valve classification

Local and international solenoid valves are divided into three categories in principle (like: direct-acting, step-by-step direct-acting, pilot-operated). They are divided into six branches from the difference in structure and material of valve disc and the difference in principle (direct-acting diaphragm structure, step-by-step diaphragm structure, pilot-operated diaphragm structure, direct-acting piston structure, step-by-step piston structure, pilot piston structure). We would introduce three aspects: introduction, principle and characteristics.

1. Direct acting solenoid valve

Introduction:
There are two types: normally closed and normally open. The normally closed type is in a closed state when the power is off. When the coil is energized, an electromagnetic force is generated, so that the moving iron core overcomes the spring force and the static iron core is attracted to directly open the valve, and the medium is in a path. When the coil is powered off, the electromagnetic force disappears, the moving iron core is reset under the action of spring force, the valve port is directly closed, and the medium is blocked. The structure is simple, the action is reliable, and it works normally under zero pressure difference and micro-vacuum. Normally open is just the opposite, such as a solenoid valve with a flow diameter smaller than φ6.

Principle:
When the normally closed type is energized, the electromagnetic coil generates electromagnetic force to lift the opening piece from the valve seat, and the valve opens. When the power is off, the electromagnetic force disappears, the spring presses the opening piece on valve seat, and valve opens. (Normally open is the opposite of this)

Özellikler:
It can work normally in vacuum, negative pressure and zero pressure, but the diameter generally does not exceed 25mm.

2. Processing direct-acting solenoid valve

Introduction:
This kind of valve adopts the one-time opening valve and the second-time opening valve to connect together. The main valve and the pilot valve step by step make the electromagnetic force and pressure difference directly open the main valve port. When the coil is energized, electromagnetic force is generated to make the moving iron core and static iron core pull together, the pilot valve port is opened and pilot valve port is set on the main valve port, and the moving iron core and the main valve core are connected together. The pressure of cavity is unloaded through the pilot valve port, and the main valve core moves upward under the simultaneous action of pressure difference and the electromagnetic force, opening the main valve medium to flow. When coil is powered off, the electromagnetic force disappears. At this time, the moving iron core closes pilot valve hole under the action of its own weight and spring force. At this time, the medium enters the upper cavity of main spool in the balance hole, which increases pressure in the upper cavity. The main valve is closed under the action of spring return and pressure, and the medium is cut off. Reasonable structure, reliable action, and reliable operation under zero pressure difference, such as: ZQDF, ZS, 2W, etc.

Principle:
It is a combination of direct action and pilot type. When there is no pressure difference between the inlet and the outlet, after the power is turned on, the electromagnetic force directly lifts the pilot valve and the main valve closing member upwards in turn, and the valve opens. When the inlet and outlet reach the starting pressure difference, after the power is turned on, the electromagnetic force pilots the small valve, the pressure in the lower chamber of the main valve rises, and the pressure in the upper chamber drops, so that the main valve is pushed up by the pressure difference. When the power is off, the pilot valve uses a spring. The force or medium pressure pushes the closing member, moving downward, causing the valve to close.

Özellikler:
It can also operate under zero pressure difference or vacuum and high pressure, but the power is large and it must be installed horizontally.

3. Indirect pilot solenoid valve
Introduction:
This solenoid valve is composed of a pilot valve and a main spool to form a channel combination; the normally closed type is in a closed state when it is not energized. When the coil is energized, the generated magnetic force makes the moving iron core and the static iron core pull together, the pilot valve port is opened, and the medium flows to the outlet. At this time, the pressure in the upper chamber of the main valve core is reduced, which is lower than the pressure on the inlet side, forming a pressure difference to overcome the spring. The resistance will move upwards accordingly to achieve the purpose of opening the main valve port, and the medium will flow. When the coil is powered off, the magnetic force disappears, and the moving iron core resets and closes the pilot port under the action of the spring force. At this time, the medium flows in from the balance hole, the pressure in the upper cavity of the main spool increases, and moves downward under the action of the spring force. Close the main valve port. The normally open principle is just the opposite.

 

3. Features of solenoid valve

1. External leakage is blocked, internal leakage is easy to control, and it is safe to use
Internal and external leaks are elements that endanger safety. Other automatic control valves usually extend the valve stem, and the rotation or movement of the valve core is controlled by electric, pneumatic and hydraulic actuators. All this needs to solve the problem of external leakage of the dynamic seal of the long-term action valve stem. Only the solenoid valve is completed by electromagnetic force acting on the iron core sealed in magnetic isolation sleeve, and there is no dynamic seal, so the external leakage is easy to block. The torque control of electric valve is not easy, it is easy to cause internal leakage, and even the head of valve stem is broken. The structure of solenoid valve is easy to control the internal leakage until it drops to zero. Therefore, the solenoid valve is particularly safe to use, especially for corrosive, toxic or high and low temperature media.

2. The system is simple, easy to connect to the industrial computer, and the price is low
Solenoid valfın kendisi basit bir yapıya ve düşük fiyata sahiptir ve kurulumu ve bakımı kontrol valfleri gibi diğer aktüatör türlerinden daha kolaydır. Daha da önemlisi, oluşan otomatik kontrol sistemi çok daha basit ve çok daha ucuzdur. Solenoid valf bir anahtar sinyali ile kontrol edildiğinden, endüstriyel bilgisayara bağlanmak çok uygundur. Bilgisayarların popülaritesi ve düşen fiyatlar çağında, solenoid valflerin avantajları daha açıktır.

3. Action, small power, light appearance
Solenoid valve response time can be as short as several milliseconds, and even pilot-operated solenoid valves can be controlled within tens of milliseconds. Because of its own loop, it is more sensitive than other automatic control valves. A properly designed solenoid valve coil has low power consumption and is an energy-saving product. It can also be achieved only by triggering the action to automatically maintain the valve position without power consumption at all. The solenoid valve has a small size, which saves space and is light and beautiful.

4. The adjustment accuracy and applicable medium are limited
Solenoid valves usually only have two states of on and off, the valve core can only be in two extreme positions, and cannot be adjusted continuously. The solenoid valve has high requirements on the cleanliness of the medium, and the medium containing particles cannot be applied. If it is an impurity, it must be filtered out first. In addition, viscous media cannot be used, and the range of media viscosity suitable for specific products is relatively narrow.

5. Diverse models and wide range of uses
Although the solenoid valve has inherent deficiencies, its advantages are still very prominent, so it is designed into a variety of products to meet various needs and has a wide range of uses. The advancement of solenoid valve technology also revolves around how to overcome congenital deficiencies and how to make better use of inherent advantages.

 

4. Solenoid valve selection

1. Economical
There are many solenoid valves that can be used in general. In the process of selection, the most economical product should be selected, but it must be economical on the basis of safety, application and reliability. Economy is not only the price of product, but also its function and quality, as well as the cost of installation, maintenance and other accessories. The most important is the cost of a solenoid valve in entire automatic control system and even in the production line is very small. If it is greedy for small and cheap and wrongly selected, it will cause huge damage. In a word, economy not only refers to product price, but also product performance-price ratio to comprehensive cost-price ratio.

2. Security

(1) Corrosive medium: plastic king solenoid valve and all stainless steel should be used. For strong corrosive medium, isolation diaphragm type must be used. For neutral medium, it is also advisable to use a solenoid valve with copper alloy as the valve casing material. Otherwise, rust chips often fall off in the valve casing, especially in the occasions where the action is not frequent. Ammonia valves cannot be made of copper.

(2) Explosive environment: Products with corresponding explosion-proof grades must be selected, and waterproof and dust-proof varieties should be selected for outdoor installation or in dusty occasions.

(3) The nominal pressure of solenoid valve should exceed the maximum working pressure in the pipe.

3. Reliability

(1) Working life, this item is not included in the factory test item, but belongs to the type test item. In order to ensure the quality, brand-name products from regular manufacturers should be selected.

(2) Work system: There are three types of long-term work system, repeated short-time work system and short-time work system. For the case where the valve is opened for a long time and only closed for a short time, a normally open solenoid valve should be used. When used in short-time working system and large batches, special orders can be made to reduce power consumption.

(3) Operating frequency: When the operating frequency is required to be high, the structure should preferably be a direct-acting solenoid valve, and the power supply should preferably be AC.

(4) Operasyonel güvenilirlik: Kesinlikle, bu test resmi olarak Tayvan'daki solenoid valfler için profesyonel standartlara dahil edilmemiştir. Kaliteyi sağlamak için düzenli üreticilerin marka ürünleri seçilmelidir. Bazı durumlarda, eylem sayısı fazla değildir, ancak yangın önleme ve acil durum koruması gibi güvenilirlik gereksinimleri yüksektir, hafifçe alınmamalıdır. Arka arkaya iki kez çifte sigorta özellikle önemlidir.

4.Uygulanabilirlik

(1) Ortam özellikleri
1.1 Gaz, sıvı veya karışık durum için farklı tipte solenoid valfler seçin. Hava için ZQDF, sıvı için ZQDF-Y ve buhar için ZQDF-2 (veya -3) gibi, aksi takdirde arızaya neden olmak kolaydır. ZDF serisi çok fonksiyonlu solenoid valf gaz ve sıvıyı birbirine bağlar. Yükleme kullanıcısının modu ayarlaması gerekmemesi için sipariş verirken medyanın durumunu bildirmek en iyisidir.
1.2 Farklı özelliklere sahip ürünlerin farklı ortam sıcaklıkları vardır, aksi takdirde bobin yanar ve contalar yaşlanır, bu da servis ömrünü ciddi şekilde etkiler.
1.3 orta viskozite, genellikle 50 cst'nin altında. Bu değer aşılırsa, çapı 15 mm'den büyük olanlar özel sipariş için ZDF serisi çok fonksiyonlu solenoid valf kullanmalıdır. 15 mm'den küçük çaplı yüksek viskoziteli solenoid valfler sipariş edin.
1.4 Ortamın temizliği yüksek olmadığında, solenoid valfın önüne bir geri yıkama filtre valfi takılmalıdır. Basınç düşük olduğunda, doğrudan etkili diyaframlı solenoid valf kullanılabilir.
1.5 Ortam yönlü bir döngü ise, karşı akıma izin verilmez ZDF-N ve ZQDF-N'nin sadece çift yönlü bir döngü kullanması gerekir, lütfen özel gereksinimler yapın.
1.6 Ortam sıcaklığı solenoid valf tarafından izin verilen aralıkta seçilmelidir.

(2) Boru parametreleri
2.1 Ortam akış yönü gereksinimlerine ve boru hattı bağlantı yöntemine göre valf çapını ve modelini seçin.
2.2 Valfin akış hızına ve Kv değerine veya borunun iç çapına göre nominal çapı seçin.
2.3 Çalışma basıncı farkı, minimum çalışma basıncı farkı 0.04MPa'nın üzerinde olduğunda dolaylı pilot tipi kullanılabilir; Minimum çalışma basıncı farkı sıfıra yakın veya sıfıra yakın olduğunda, doğrudan etkili veya kademeli doğrudan kullanılmalıdır.

Kaolu'nun solenoid valf ürün seçimi için lütfen şu adresi ziyaret edin:
https://www.genndih.com/