water tank control

Consider using Baldor with an IP65 enclusure box.

What equipment are you asking about? the frequency drive? the pump? the motor? the flowmeter?

frequency drive – we use telemecanique, allen-bradley, and danfoss. Practically speaking any of them will do but you'll probably to have them in IP65 enclosures in your case.

the pump – not my area of expertise but your local supplier might be able to give you an appropriate unit based on you specifications.

the motor – again, we use different brands (though, personally, I'd prefer we use only one. Unfortunately, I'm not the only one who makes these decisions). For corrosive environments, there are models that are built of stainless steel, with IP65 rating, hermetically sealed.

flowmeters - we use Yokogawa but that's a personal choice as I've never had problems with them. Talk with your supplier about the appropriate model based on you application.

I should have stated it differently we want to control the level of water in tank #2 by controling the speed of the pump useing a 4/20/mlamp or 0>10 vdc level sensor

What you need to do is create a system curve by analyzing both pump curves against the system demand variances. If the pumps as designed have the capacity to balance each other, it is then simply a matter of set points. Do you already have all the equipment purchased? The drive software will be critical. That is why we us The Yaskawa IQ drives, their software is very easy to set up.

Well now, that clears things considerably!

I've already given you the brands that we use for motors and variable-frequency-drives. For level instruments we use Rosemount (by emerson) mostly. All you need to do it ask your supplier for the particular model that can satisfy your conditions.

These are pressure-type level transmitters, by the way. If your Tank#2's contents are clean (as in no sediments), they'll be okay. If your fluid has sediments, I'd use other technologies.

One of these is load cells or weight-sensors. Instead of measuring the level, you measure the weight and convert it to level. For these, we use Sartorius. Their load cells are good and the new transmitters are easy to use.

There are lots of other level measuring technologies and putting them all here is going to take a lot of time (not to mention typing). Maybe the others can provide additional information.

Guys...?

Go to your nearest Kobold distributor, he'll fix you right up. That exercise is almost too easy, if you know how.

On the subject of a pump, a gear pump with a magnetic coupler should work. It all depends on the harsh environment/water you are talking about. Isochem has a variety of gear pumps depending on the application. (flow rates, pressure, chemicals being transferred, etc.) They are very reliable.

Hi! what is the flowrate of water we are talking about? is it hughes or just a 1000 liters per min flow? you need to mention the flow. There are various type of flow control system. However, the best thing we can analyze your problem is... you need to give at least a simple diagram of the system to analyze for the best solution. if am not mistaken, analog signal will give on/off only to pump but not modulation.

jojie_oak@yahoo.com

Maybe your control process statement sounds more complicated than is.

All you need are 2 intermediate sumps with2 level switches to DOL control the transfer pump motors.

Corrosion,Explosionproofing drive motors are other issues best handled on their own merits.

Simple on/off control via level switches is the simplest and most common. Unless your application calls for dynamic control of point level. In this case things begin to complicate quickly depending on the process needs. Now, Have you thought about what´s going to drive your VFD ?

I am a pump supplier. I use IFM Effector with Yaskawa IQ pump drives for this type of application.

Good luck,

Joe T.

Why can't the water be put back into tank#1 instead of going via tank#2? If it could then one wouldn't need a flowmeter and a variable speed drive on pump no.2. A Portsmouth Valve http://en.wikipedia.org/wiki/Ballcock on tank no.1 would do the job instead.