LEVEL TRANSMITTERS - Selecting the "RIGHT" equipment!

In proportional level control, �one size does not fit all�.

Unfortunately, there is no single measurement technology that satisfies the variety of applications encountered in the process industry.� Selecting the best level instrument for a given application involves reviewing the application without missing a single detail.

First the most appropriate technology must be determined.

This guide has been prepared to make the Princo technology selection process easy.� The technology matrix shown below provides a list of key characteristics of each technology. By simply evaluating the significance of these characteristics in your application, you can easily select the RIGHT technology.

Level Transmitter Technology Matrix

Once the technology has been selected, then the specific application requirements such as: electrical parameters, process material (temperature, pressure, viscosity, classification, wash down, compatibility, agitation, foaming, buildup, vapors, etc.), vessel configuration, and mounting, must all be addressed.

Typical issues include:

Does the sensor come in the required length or range to suit the application?

Can the sensor be simply installed, or must unique mounting hardware be specified?

Are there any internal devices within the vessel, or conditions such as spraying or splashing liquids that will interfere with the sensor chosen? If yes, can they be easily and affordably overcome and still allow a low-cost sensor solution?

How critical is the accuracy of the sensor in the application? Can a more accurate sensor reduce inventory to the point where payback is achieved in a few months?

How important is safety in the application? Does the sensor need a specific agency approval for use?

Does the sensor provide the needed electrical interface for present and future plans of operation? Will the electrical installation require additional enclosures to house intrinsic safety barriers, interposing control relays, etc.?

Installation issues to consider:

Most level sensors are designed for simple installation into standard flanges and pipe fittings, with tapered pipe threads being the norm. Questions regarding installation are driven mainly by the mechanical design of each sensor.� Don�t assume a sensor will fit without a thorough review of all the mechanical dimensions.

For ultrasonic sensors a clear beam field to prevent false signal returns is preferable. Ensure that the distance from sidewall obstructions or fill points is adequate. In worse case conditions installation within a vertical column of piping is done to reduce surface turbulence and shield the beam from splashing liquid. Would your particular installation allow pipe insertion?

RF Impedance/Capacitance sensors may require an additional reference electrode if the vessel is lined or made of plastic, to provide an adequate ground reference. If this is necessary, does it require problematic adaptation of the vessel lid?

Does the vessel cover need a self-aligning bulkhead fitting to keep the sensor vertical?� By reviewing the installation instructions before specifying the instrument, you can avoid installation problems.

Is the process level stable, or does it vary considerably due to filling or emptying? A level sensing system will generally only be as accurate as the condition of the material being measured. Sloshing and splashing fluids will require rather heavy averaging, which may reduce system response time.

Because there are so many factors to consider, Princo has prepared an application specification form, (see below) which when used, will remind you to evaluate all of the numerous parameters that can have an impact on the success of your level control application.

At Princo Instruments, we are totally dedicated to providing you with best possible solution for your level control application.��

Rather than evaluating and specifying the equipment yourself, at NO COST, you can have the Princo professional engineering staff review your application, recommend a system and �guarantee� the results.� In order for us to do that we need some basic information about you and your application.��

You can either download an Application Form file in either Microsoft Word format DOC (right click here) or Adobe Acrobat PDF (right click here) format, complete it, and FAX it back to us or you can provide this info on-line by filling out and submitting the form below.

In either case, please fill out the questionnaire, entering all the information that applies to your application.� Once we receive it, we will promptly respond with a recommended solution for your application.�