Can a solenoid valve generate electricity

FAQ

FAQ, questions and answers

Here you will find explanations of the different functions of solenoid valves and the most frequently asked questions are answered.

1. What is the difference between direct operated, pilot operated and forced operated?

2. What do NC and NO mean?

3. How does a direct operated solenoid valve NC or NO work?

4. How does a pilot operated solenoid valve NC or NO work?

5. How does a positively controlled NC solenoid valve work?

6. What is a 3/2 way solenoid valve?

7. Which solenoid valve is suitable for garden irrigation?

8. Which solenoid valve do I use for vegetable oil changeover?

9. Which valve is suitable for closed systems?

10. Which valve can I use for higher pressures, for example 70 bar CO2 bottle?

11. What do AC and DC mean in the voltage specifications?

12. How do I determine the thread, conversion inches / mm?

13. Correct application conditions for solenoid valves and other components

14. Electrical connection of solenoid valves

15. What do NW nominal size mean

16. Information on switching times

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1. What is the difference between direct operated, pilot operated and forced operated?

Direct operated solenoid valves do not require a minimum operating or differential pressure for the switching function, they work from 0 bar.

Pilot operated valves work according to the differential pressure or servo principle and use the pressure of the medium to open and close the valve seat. The respective minimum operating pressure is required here as a differential pressure.

Forced control solenoid valves are a combination of direct and indirect (pilot operated) actuation. A mechanical connection between the armature (pilot stage) and the diaphragm supports the opening movement of the diaphragm. This is known as forced control or forced increase. In contrast to the pilot operated valves, a minimum pressure difference is not required for this combined mode of operation, which means that the solenoid valve works from 0 bar on.

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2. What do NC and NO mean?

NC is closed when de-energized

NO is open when de-energized

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3. How does a direct operated solenoid valve NC or NO work?

2/2 way solenoid valves directly controlled, normally closed (NC function)
Direct operated solenoid valves do not require a minimum operating or differential pressure for the switching function, they work from 0 bar.
The sealing element is coupled to the anchor (core). In the de-energized state, the valve is closed and the core with its seal is pressed onto the valve seat by the spring force, supported by the medium pressure.

 

The maximum operating pressure and the volume flow depend directly on the seat diameter (DN) and the magnetic force.

If voltage is applied to the magnet, the armature with the seal is drawn into the magnet coil and the valve opens.

 

The maximum operating pressure and the volume flow depend directly on the seat diameter (DN) and the magnetic force.

2/2 way solenoid valves directly operated, normally open (NO function)
Direct operated solenoid valves do not require a minimum operating or differential pressure for the switching function, they work from 0 bar. The sealing element is coupled to the anchor (core). In the de-energized state, the valve is open and the core with its seal is held by the spring force in a position that leaves the valve seat free and thus enables the medium to flow through.

If voltage is applied, the armature (core) with the seal is pushed downwards and presses the seal into the seat using the rod and closes the valve.

 

The maximum operating pressure and the volume flow depend directly on the seat diameter (DN) and the magnetic force.

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4. How does a pilot operated solenoid valve work?

2/2 way solenoid valves pilot operated, normally closed (NC function)
Pilot operated valves work according to the differential pressure or servo principle and use the pressure of the medium to open and close the valve seat. The pilot control system acts as an amplifier, so that fluids with large volume flows at higher pressures can be controlled with a magnet with low force. Both pistons and diaphragms are used as sealing elements for the main seat.

Function description:

The solenoid valve is closed.

The electromagnet is de-energized and its armature closes the extraction hole (pilot seat). The inlet pressure in 1 (greater than the outlet pressure in 2) builds up through the mounting hole in the membrane on the upper side of the membrane. This pressure, multiplied by the area of ​​the top of the membrane, generates a closing force that is greater than the opening force acting on the membrane. She is pressed into her seat.

The solenoid valve opens.

There is voltage on the magnet. The magnetic force, greater than the closing force acting on the armature (spring and pressure force), lifts it from the extraction hole. This relieves the pressure on the space above the membrane and the pressure is equal with side 2 of the valve. This pressure relief remains, since less fluid can flow in through the build-up bore than escapes through the build-up bore. Thus, the opening force, resulting from the higher inlet pressure in 1 on the diaphragm, predominates. It lifts off the valve seat and the valve remains open as long as the prescribed pressure difference from 1 to 2 is present. Depending on the valve type, this is 0.1 to 1 bar.

The solenoid valve closes. The solenoid is switched off and the armature closes the extraction hole through the spring and pressure force. The same pressure builds up above the diaphragm as on side 1 and the resulting force presses the diaphragm onto the valve seat.
The direction of flow of the medium is fixed.

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2/2 way solenoid valves pilot operated, normally open (NO function)

Function description:

The solenoid valve is open.

 

In the de-energized state, the valve is open and the armature with its seal is held by the spring force in a position that leaves the valve seat free and thus triggers the opening of the main seat and enables the medium to flow from 1 to 2.

2/2 way solenoid valves pilot operated, normally open (NO function)

The solenoid valve is closed.

 

If voltage is applied to the magnet, the armature with the seal is moved downwards and, by means of the rod, presses the seal into the seat and closes the dismantling hole (pilot seat).

The inlet pressure in 1 (greater than the outlet pressure in 2) builds up through the mounting hole in the membrane on the upper side of the membrane. This pressure, multiplied by the area of ​​the top of the membrane, creates a closing force that is greater than the opening force acting on the membrane. It is pressed onto its seat and prevents the medium from flowing through from 1 to 2.

The solenoid valve opens

If the magnet is de-energized, the armature opens the extraction hole by the spring force. This relieves the pressure on the space above the membrane and the pressure is equal with side 2 of the valve. This pressure relief remains, since less fluid can flow in through the build-up bore than escapes via the breakdown bore and thus enables the medium to flow through again from 1 to 2.
The direction of flow of the medium is fixed.

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5. How does a positively controlled NC solenoid valve work?

2/2 way solenoid valves with forced control, normally closed (NC function)

Forced control solenoid valves represent a combination of direct and indirect (pilot operated) actuation. A mechanical connection between the magnet armature (pilot stage) and the diaphragm supports the opening movement of the diaphragm. This is known as forced control or forced increase. In contrast to the pilot operated valves, a minimum pressure difference is not required for this combined mode of operation, which means that the solenoid valve works from 0 bar on.

In the case of positively controlled solenoid valves, the solenoid coil is very often designed to be more powerful, since if there is no pressure difference, it has to open the valve without pressure support. Solenoid valves with forced control combine the advantages of direct actuation (no minimum pressure / flow rate required) and indirect actuation (relatively large volume flow at high pressures).

Function description:

The solenoid valve is closed.

The electromagnet is de-energized and the armature closes the dismantling hole in the center of the membrane (pilot seat), the valve is closed. The inlet pressure in 1 (greater than the outlet pressure in 2) builds up through the mounting hole in the membrane on the upper side of the membrane.
This pressure, multiplied by the area of ​​the top of the membrane, generates a closing force that is greater than the opening force acting on the membrane. The membrane is pressed onto its seat.

The solenoid valve is open.

There is voltage on the magnet. The magnetic force, greater than the closing force acting on the armature (spring and pressure force), lifts it from the extraction hole.

This relieves the pressure on the space above the membrane and the pressure is equal with side 2 (valve outlet).

This pressure relief remains, since less fluid can flow in through the build-up bores than escapes through the build-up bore. Thus, the opening force predominates, resulting from the higher inlet pressure in 1. The pressure difference between the upper and lower side of the diaphragm lifts the diaphragm away from the valve seat. This opening process is therefore identical to that of the valves with indirect actuation. It differs from this, however, that after a certain armature stroke the diaphragm is pulled into the open position by the magnet armature at the same time via a driver stop, the mechanical coupling.

No pressure difference is therefore required to open the valve and keep it open.

The solenoid valve closes:

The magnet is switched off and the armature closes the extraction hole by means of the spring force (and pressure force, if available).

Above the membrane, the same pressure builds up again via the mounting hole as on side 1 and the resulting force presses the membrane onto the valve seat. If there is no or very little differential pressure, this closing process takes place solely through the force of the springs in the armature tube above the membrane.
The direction of flow of the medium is fixed.

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6. What is a 3/2 way solenoid valve?

Directly controlled 3/2 way solenoid valves do not require a minimum operating or differential pressure for the switching function, they work from 0 bar.
They have three connections (1, 2 and 3) and the armature (core) has two valve seats. One valve seat always remains open or closed alternately.

Function description:

The mode of operation of the solenoid valve depends on the connection assignment, i.e. how the connections are connected to the fluid system.

The solenoid valve is closed.

 

Port 1 is connected to the inlet that carries the medium and port 2 forms the valve outlet. Port 3 is the vent or return.
The electromagnet is de-energized and the armature (core) with its seal is pressed onto the lower valve seat by the spring and blocks port 1 (inlet). Port 2 (output) is connected to port 3 (return).

Directly controlled 3/2 way solenoid valves do not require a minimum operating or differential pressure for the switching function, they work from 0 bar.

The solenoid valve is open.

Voltage is applied to the magnet and the armature (core) is drawn into the magnet coil, whereby the armature with its upper seal is pressed onto the upper valve seat by the spring.
Port 3 (return) is now shut off. Moving the armature upwards also opens the lower valve seat and the medium can flow from port 1 (inlet) to port 2 (outlet).
In these solenoid valves, an increase in pressure causes the force required to open the valve to decrease. If the pressure difference between the inlet and outlet (consumption) is greater than the maximum value for which the solenoid valve was designed, the solenoid valve can also open without voltage being applied to the solenoid.

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7. Which solenoid valve is suitable for garden irrigation?

All pilot operated solenoid valves are suitable for this. The backflow necessary to open the valve is created by the consumers, who are usually connected.

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8. Which solenoid valve do I use for vegetable oil changeover?

The 3/2 way PÖL valves are used for this. The valves suitable for this are marked with PÖL. When searching via the search window, entering the word "PÖL" gives you all hits.

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9. Which valve is suitable for closed systems?

In closed systems such as heating systems, the pressure above the valve is usually not known. In such cases, positively controlled valves should be used.

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10. Which valve can I use for higher pressures, for example 70 bar CO2 bottle?

For such applications we have extra solenoid valves that can switch high pressures. These can be found with the direct operated valves.

 

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11. What do AC and DC mean in the voltage specifications?

AC stands for alternating voltage. e.g. 230V house supply

DC means direct voltage. e.g. car 12 V / DC

 

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12. How do I determine the thread, conversion inches / mm?

Thread ISO 228
Pipe thread BSP (British Standard Pipe)
Pipe thread for connections not sealing in the thread (cylindrical)

description

diameter
inch

Ø outside
mm
Ø mother
mm
Ø core hole
mm
Aisles /
inch
pitch
mm
G1 / 8 "1/89,738,858,80280,907
G1 / 4 "1/413,1611,8911,8191,337
G3 / 8 "3/816,6615,3915,25191,337
G1 / 2 "1/220,9519,1719,00141,814
G5 / 8 "5/822,9121,1321,00141,814
G3 / 4 "3/426,4424,6624,5141,814
G1 "133,2530,9330,75112,309
G1 1/4 "1 1/441,9139,5939,25112,309
G1 1/2 "1 1/247,8045,4845,25112,309
G2 "258,6157,2957,00112,309
G2 1/2 "2 1/275,1872,8672,60112,309
G3 "387,8885,8685,30112,309
G3 1/2 "3 1/2100,3398,0197,70112,309
G4 "4113,03110,71110,40112,309

 

 

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13. Correct application conditions for solenoid valves and other components so that you can enjoy the technology for a long time

Sometimes valves are operated under conditions that can lead to damage very quickly.

In any case, the user is responsible for observing the conditions.

Here we have put together a few tips that should be observed.

It is important that the conditions of use should be clarified beforehand. Please note, among other things

Medium temperature:

if it gets too hot, firstly it damages the sealing elements and secondly the coil can overheat, which can also destroy it

Ambient temperature:

the coils give off a large amount of heat, depending on their power. It must be ensured that this heat is also carried away

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Differential pressure

The medium itself must be compatible with the materials used. To clarify this, you can use chemical resistance lists to check whether it fits. These lists can be found on the Internet using search engines, for example, or you can ask us.

Electrical connection:

Even if the valves are IP55 or IP65, they are not necessarily waterproof. The IP grade only says something about the protection against accidental contact. Coils are largely made of polyamide, which absorbs moisture and then the coil burns out. This is particularly important for 230 V / AC, since flashovers can occur more quickly in the coil; this was not observed that often with low voltage, but should still not be used for this.

Valves should always be installed in such a way that condensation can always dry off quickly or, better yet, that it does not arise at all. Installation only in dry rooms. The installation in locked boxes, boxes, well shafts or the like or cans is also questionable, since the resulting humidity can be absorbed by the coils. We have already seen that "normal" solenoid valves are buried in a bag in the garden does not go well for long. It's like being in a greenhouse, the coils suck up full over time and then eventually the coil burns out.

The same applies to the development of heat, the heat must be able to get away from the coils, otherwise they can overheat and be damaged.

If you are planning such extreme operations, it is better to ask in advance by email. Describe the planned assignment as precisely as possible, then we can see whether we can offer something suitable.

Valves must be installed so that they are protected from frost or they should be dismantled in winter if there is a risk of frost.

If the medium is not clean, it is advisable to connect a dirt trap in front of it.

Deposits from the medium can also impair the function, in which case regular cleaning of the valves should be planned.

The more closely you observe the conditions of use, the longer the valves will function without any problems.

 

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14. Electrical connection of solenoid valves

The solenoid valves are connected by means of flat plugs or device plugs. The two opposite contacts are for the voltage: + and - do not matter how around with DC, with AC zero and phase do not matter. The lower contact is for the protective conductor at 230V AC, at low voltage it can remain free. The contact has a direct connection via the inside of the coil to the metal housing.

 

15. What does NW nominal size mean

The nominal size provides information about the narrowest point in the valve, usually the valve seat. The connection size can definitely be G3 / 4 "but the nominal diameter is only 0.8mm. As a rule, the switchable pressure of the valve also decreases with increasing nominal diameter.This information is stored in the description of each valve; this information must be observed. 16. Information on switching times of valves
  Opening and closing times cannot always be seen exactly in advance, as they depend on many factors. Medium, pressure, differential pressure, flow speed, consumer behind the valve, temperature and much more. Therefore, the manufacturers cannot provide any precise information in advance. Only a "from to" range, if any, is predictable. For example, switching times of 20ms to 5s (rough information) are possible depending on the application, valve design, manufacturer and conditions of use. As a guideline, one can take that direct operated valves close faster than forced operated valves. Piloted valves work more slowly because the differential pressure has to be established first. Measured under the same conditions of use. If more detailed information is required, please ask in writing. To do this, we need the exact purpose of use with all the relevant information, otherwise the manufacturer cannot provide any information. In no case should one assume that slowly closing valves in principle cannot trigger any pressure surges in the system. Only special valves are guaranteed to be shock-free E.g. with progressive closing where the manufacturer specifies or the AVS GAMMA valves, these are advertised by the manufacturer as low-noise and impact-free closing.  

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