I’m looking for a PWM actuator for central heating manifolds with a 30x1.5 thread, up to 100 zł

Hello,
I’m planning to set up a comprehensive building control system for lighting, ventilation, heating, etc. I’ll be using a manifold with around 7–8 sections. I’d like to be able to control this manifold smoothly, i.e. adjust each section from 0–100 per cent. All the actuators currently available operate in 0/1 mode (NO or NC), and they also draw power continuously whilst under control.
I’ve looked everywhere for an actuator where I could send a signal – for example, a PWM signal – and it would move to the set position and remain there. It should also have a mounting suitable for a standard manifold valve, i.e. with a 30x1.5 thread. And at a reasonable price – up to about 100 zł.
If anyone has heard of anything like this, please do let me know. I’d be very grateful. I’ve been looking for this for a few months now, but I can’t find it anywhere.
I’d also planned to make something out of a model-making servo; the power and control would be sufficient, I just need an eccentric shaft or a small trapezoidal screw or something similar. Perhaps someone has heard of such a design.

Many thanks in advance for any suggestions and information.

There’s quite a bit of it here: http://www.ojelectronics.pl/SI%C5%81OWNIK-ZAWORU-MIESZAJ%C4%84CEGO-4461.aspx
0–10 V voltage control via the third wire.

Or Heimeier: http://www.tahydronics.com/pl/Produkty-i-rozw...-and-control/zawory-regulacyjne/siowniki/EMO/
Control via a third wire using 0–10V or 2–10V; there are also versions with EIB and KNX bus connectivity.
But the price of these devices starts at 1,000 zł each......

Perhaps it’s best not to go down the PWM control route, but to use standard actuators for open/close valves and control them via operating time (such motors take around 100 seconds for a full cycle, so you could achieve reasonable accuracy using operating time) and any misalignments could be corrected by adjusting them every so often (you’d have to move them at least once a week anyway, as they tend to seize up).
But unfortunately, even these simple ones cost around 300 zł (some no-name ones for 200).
There are also thermoelectric devices for 50 zł that work on the same principle as a car thermostat (a heating element heats paraffin or another solvent, and a piston pushed by the paraffin opens the valve), but these are typically open/close valves for radiators.

PS. A small suggestion – if you’re building it yourself and precise control is essential, perhaps you could use an encoder (pulse generator) on the drive motor instead of PWM – it’s easier for a microcontroller to count pulses than to generate precise timing waveforms with variable duty cycles (and you’ll need a PWM decoder on the actuator side or a factory-fitted servo for this).

PLATKOM wrote:

Hello,
I’m planning to set up an extensive building control system for lighting, ventilation, heating, etc. I’ll be using a manifold with around 7–8 sections. .....

What do you intend to base the whole system on?
8 sections – about 20W each; let’s say they consume 250W/day * 30 = 4.5 zł a month – compared to heating costs, that’s peanuts...

If you’re considering an integrated control system, think about NEXO and Nexwell’s WPP programmable buttons, http://www.nexwell.eu/produkt/nxw2974-wielofunkcyjny-przycisk-programowalny-tukan, which include a temperature sensor. With an 8-channel relay module, you can control these actuators as required, depending on the temperature needs in the rooms.
Regards

Thank you for your interest and all your replies.

‘kotbury’:
As for those first actuators, that’s pretty much what I had in mind, but in a smaller housing. Besides, the price alone is daunting. I’ve found similar ones for almost 10 times less: http://www.geothermie.pl/pg-14-154.html-title-silownik-s21.html .
These would be almost perfect because I can set them to any position, switch off the power, and they’ll stay that way. It’s just that they’re too wide and won’t fit on my manifold.

Mate “kasprzyk”:
As for those calculations, you’re right – there are supposedly four of those manifolds, so it works out at about 250 zł a year, assuming they’re “controlled” for 10 hours a day – which is neither a lot nor a little.
I think it would also be possible to control them almost from 0–100 using ‘pseudo-PWM’, i.e. by varying the power supply time. The time it takes for them to close and open is about 3 minutes.
I was thinking more along the lines of some sort of model-making servo, costing about 10–20 zł, mounted above the valve with a bolt and nut, controlled by PWM to cut off the power supply and leave it like that. If I had an idea for a housing with a standard nut for manifolds, I’d probably come up with something. If nothing suitable turns up, I’ll use the standard ones from radiators.

This programmable panel is very interesting (and I liked their other solutions too, for that matter); I’d like to use something similar, but to control not only the heating but also the lighting, air conditioning, ventilation, etc.

As for the system itself, I want to base it on my own system, because I’d like this building to ‘have a life of its own’.

Actually, what sort of valves does your manifold have? – the kind with pin valves for underfloor heating and thermostats, or the standard type with ball valves? (because if they’re for thermostats, you might as well forget about proportional control – that sort of valve has a stroke of 1.5–2.5 mm)

Quote:

As for those first actuators, that’s pretty much what I had in mind, but in a smaller housing. Besides, the price alone is daunting. I’ve found similar ones for almost 10 times less: http://www.geothermie.pl/pg-14-154.html-title-silownik-s21.html .
These would be almost perfect because I can set them to any position, switch off the power, and they’ll stay that way. It’s just that they’re too wide and won’t fit on my manifold.

These actuators aren’t proportional, just on/off (especially the one with single-wire control), and their high operating speed (6–15 seconds) rules out time-based control – these are the ones I mentioned: “some no-name ones for 200 zł”

Quote:

I was thinking more along the lines of a model-making servo, costing around 10–20 zł, mounted above the valve with a bolt and nut, controlled via PWM; switch off the power and it stays that way

Again, it depends on what sort of valves you have – if they’re pin valves, a standard servo (30–50 zł) plus a rotary cam and a disc, or a long-stroke screw with a nut, will do; if they’re ball valves, you’ll need a giant servo (50–120 zł). Model servos have a rotation angle of 90 (sometimes 120) degrees, so you’ll need to adapt solution 1 to this small angle.
PWM proportional servos only draw current whilst moving – when at rest, they draw current only to power the electronics.

It might be a bit late in the day, but you can use the headlight adjustment motors from a car for the distributor valves (the ones with a short stroke); the lever extends by about 6mm, which is more than enough. I’m currently working on a control system for the four-way valve myself and testing various actuators.