Rotary Solenoids

[Snot]

Hi All,

I am starting a project where I will need to turn on a number of taps electronically. I presume I will need to use rotary solenoids but I don't know much about them and looking at the usual sources (Farnell and RS) they seem to be very expensive. The taps I wish to turn on are similar to this.

Plastic Inline Tap: Amazon.co.uk: Garden & Outdoors

I would like to keep the circuit as low power as possible as I would like to run off batteries.

Does anyone have any ideas of a solution?

Many Thanks,

Scott

 

[Syntax42]

I don't think a solenoid is the best solution for you. I have never heard of a solenoid that rotates. Besides that, solenoids will continuously draw power when in the "on" state.

There are electric water valves available for purchase on the internet, but those appear to be more expensive than what you might be looking for.

I would suggest developing a system that uses a stepper motor and a motor controller. Those can be set to rotate accurately, within a set number of degrees. This ensures you won't break the valve by turning it too far, like you would do with a standard electric motor.

 

[Reloadron]

Rather than use a solenoid of sorts to turn a valve body where you get into torque and rotational stops I believe what you want is a solenoid valve for water. Valves of this type can be expensive. However, an inexpensive choice would be to remove them from old washing machines. The problem then becomes that solenoid valves used in washing machines will run of the mains voltage in the country they were designed for. Based on your link I assume you are in the UK.

Most valves of this type I have worked with have a brass or stainless steel valve body and are expensive (depending on what you call expensive). You may be able to find some inexpensive plastic body types that use a DC coil. There are also latching types where current isn't applied to the coil constantly. Valves like this come in all flavors and designs. Normally Open or Normally Closed, shuttle types, and the list goes on. Anyway, depending on the volume and pressures involved you might do well looking for inexpensive, plastic body water type solenoid valves.

Ron

 

[KeepItSimpleStupid]

The rotary solenoid isn't going to be the right solution for you. They were common in HP X-Y recorders for the pen lift. I used them in a design for a light shutter in a monochometer light source for a piece of lab equipment. They needed a kick and a quiesenent current otherwise they got too hot.

In another piece of equipment, we used a rotary solenoid with more than one position for a filter wheel. Very difficult to manage when the system has inertia.

Standard systems use an AC synchronous motor and limit switches. DC motors could be used as well. Hobby servo motors like used for RC models probably won't have the torque.

Starting out with a torque measurement would be vital. That can be done with a bar and a weight. Multiply the arm lenght by the force to get units of say newton-meters or ft-lbs. Cans of vegtables can be used as a weight.

Those valves take a lot of force.

 

[crutschow]

I don't think a solenoid is the best solution for you. I have never heard of a solenoid that rotates.

Rotary solenoids are common. See this, for example.

But I agree that such a solenoid is likely not appropriate for this application.

 

[Snot]

Thanks, Lots of good advice there. I will take it into consideration and will let you know what happened.

 

[Reloadron]

Earlier I suggested water solenoid valves with a plastic body to cut cost these are an example from a distributor in India but they have to be available just about anywhere I would think. There are also latching versions of these basic valves. About what would be found in home appliances like washing machines and dishwashers. Additionally with low voltage DC coils. Once the application is better known it will be easier to choose a good valve. Things like line diameter, pressure, flow volume and such.

Ron

 

[KMoffett]

Rotary solenoids are common. See this, for example.

But I agree that such a solenoid is likely not appropriate for this application.

We had tons of those in clinical lab analyzer tray loaders. Still have a bunch.

Also agree, not the right solution.

Ken

 

[Neal]

How about lawn water sprinkler valve controls?

 

[Reloadron]

How about lawn water sprinkler valve controls?

Good idea.

Ron