The first thing to do is to specify some parameters:

• What is the fluid?
• What is its temperature?
• What is its pressure?
• What is its pH (acidity/alkalinity)?
• What is its viscosity?
• Is this open-channel flow or is it in some form of pipe or ducting?
• What are the dimensions of the conduit along which it is passing?
• Are there any entrained solids? If so, what sort of size?

The above will enable a first stab to be made as to the type of instrument required, and its overall size.

• What electrical connections are needed?
• How does it attach to the conduit?
• What power supply requirements does it have?
• Is there anything special, such as a zoned hazardous area to consider?

The above will enable a specific instrument to be selected.

• How is the measured flowrate to be compared with the setpoint?

The above will determine how the thing functions, and out of the bottom of all that comes the best one for the job. Then come the compromises on price and availability to fit the project......

To add to the excellent questions to be answered:

Do you need mass flow or volumetric flow measurement?

Glycol or propylene glycol with water.

Make up water temp. 32-158 tolerences

12-14 psi

8.3 - 9 ph

Closed loop

Size varies depending on system.

I hope there are no solids! Hydronic system

Power supply would be based on what type of control offered. PLC hook up as well as computer and controller considerations a must.

Flow rate to be measured based on system requirements. Flow rate not to exceed set point of set rate with a percent tolerance to yet be calculated.

Thanks

TDRI

Electromagnetic flow meter will be a solution for your needs.

You may contact

www.krohne.com

I buy a couple of different flow switches from this company- they are very knowledgeable and if you give them some details on your application I'm sure they can supply a solution. http://www.flowmetersource.com/

I do not completely understand what you ar looking for. Are you looking for a:

flowmeter (measures the flow of a fluidic medium, avialable with or without data interface),

a flow switch (only gives an output if threshold limits are met),

a flow controller (measures and control flow of a fluidic medium, data output depending on configuration and specification).

Should the device be installed in the fluid line or dou you prefer not to get into direct contac with the medium (only applicable for flowmeters or flow switches). Ultrasonic probes typically do a grea job i hydronic systems an you do not have to disrupt the fluid circuit.

nudnik

Yes. An all in one pack would be great. Ultrasonic probes sound great. What ones work the best? and what controllers work the best with these probes? We talking inputs for PLC? Reliability of these probes for long term use? I'm new to Ultrasonic. What do they talk to? Who provides these systems? ABB, Seimens, Honeywell, Allen Bradly, GE?

Hi, and Sorry for the late reply!

Well, I am not quite sure whether the use of ultrasonic probes is very common für "all in one" mass flow controllers. It is however possible to design a conrol loop consisting of a flowmeter a controller and a control valve to get the mass flow control.

If I am speaking of a mass flow controller, I usually think of a device like that: http://www.mksinst.com/product/Product.aspx?ProductID=74 http://www.bronkhorst.com/
http://www.aalborg.com/index.php/main_page/product_overview/id_product_overview/24
to mention just a few. These type of devices are available for use with gases or liquids. Due to their compact design, they are usually limited to "small" pipe diameters. If you are looking for typical large scale process control applications, the above described set-up would be used.

May I suggest that you use a search engine to identify suitable suppliers of mass flow controllers or contact a supplier of process control equipment (ABB wold be a good point to start with) to obtain technical data of their equipment and technical support for your specific application?

Regards nudnik