Select-642 Tandem Doser

There are certainly cheaper dosers on the market, but when you factor in the built in water meter, the range of products that can be dosed, the huge range of ratios that are programmed in and the very low maintenance costs, Select dosers are very cost effective.

Each Select doser is set up to receive signals from 7 flow sensors. Each of the sensors has 15 choices of ratio. These ratios can be anything from 1 : 20 to 1 : 1,000,000, although in practice the finest ratio used is 1 : 25,000 for hydrogen peroxide dosing.

The Dosatron type of doser requires you to make up a stock solution to suit the doser.

We have designed the Select doser so that you can dose product from the original container at the correct ratio without having to mix up stock solutions. You are therefore avoiding dosing inaccuracies and also avoiding coming into contact with (sometimes) aggressive products.

This problem does not exist with the Select doser. The pump can move air as well as liquid. No more downtime using a syringe to suck out air locks!

You can. This is particularly useful when the Select doser needs to be used in a field situation (pheasants, free range pigs etc.).

A 12V leisure battery charged from a solar panel is also perfectly possible.

As long as we know how many pulses we get per litre (or gallon) we can connect to any water meter. We generally supply turbine flow sensors with our dosers as these are lighter for transport and are generally more accurate at low flows.

If we used one large pump tube for all dosing ratios, at very fine ratios and very low water flows it might be several minutes before the doser was able to turn to inject product. Although this would still be accurate overall, folks prefer to see the doser operating more frequently with a smaller tube fitted.

Let us know. We can send you a new Eprom computer chip containing all of the normal ratios plus the one you need.

There are several reasons. With the dosed product kept inside the pump tube, even strongly corrosive liquids don't harm the pump, and there are no product residues in the pump to contaminate the dosed product. A win win.

Servicing of both diaphragm pumps and the Dosatron type doser can be fiddly and time consuming. Changing a pump tube in the Select doser takes around 23 seconds. This effectively services the doser.

The Select doser does not suffer from air locks. a huge advantage when dosing products that can generate gas bubbles.

It all depends on four things - the water line pressure that you are dosing into, the product being dosed, the condition of the rollers and the number of times the rotor squeezes the tube.

Choosing the correct ratio to dose the original concentrated product will save the tube being worn by pumping excess water from a stock solution. And - change the pump tube regularly to avoid it splitting. Leaked product can damage the rollers.

Almost anything. If you try to pump highly concentrated formic acid you will be out of luck. Nothing can withstand that!

The Select-640 can pump up to 20m (2 bar), while the Select-380 can pump up to 45m (4.5bar).

There is no real limit. Any restriction is only from the wall friction inside the delivery tube.

Firstly - make sure that everything is in the same units.

An example:
A product has to be dosed at 5ml per litre. A litre is 1000ml. So the ratio is 1000 divided by 5 = 200. The dosing ratio that you need to choose on the Select-doser screen is 1 : 200

Diaphragm pumps can certainly pump at a higher pressure than a Select doser, but that is pretty much the only advantage.

99% of the time there is a low pressure point on a water line to dose into. Having actual dosing ratios (and flow data) shown on-screen on a Select doser, having superb accuracy of dosing and not suffering from airlocks all count towards the Select doser being a superior choice.

Each Select Doser has a 1 year manufacturing warranty.
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