In each issue of our fLowdown e-newsletter we review a particular flow metering technique, its benefits, shortfalls and the applications to which it is best suited. In this issue we look at Differential Pressure Flow Meters.

Differential Pressure Flow Meters.
Overcoming the challenges of implementing flow technology in a medical application, By Trevor Forster

Medical facilities have many applications where precise measurement and control of flow is important. The strong appeal of establishing volume flow meter sales installed in OEM medical equipment is obvious but the route to becoming the “specified flow meter component” in this heavily regulated industry is often long and arduous. As an established OEM flowmeter supplier to this market – we share with you some of the key challenges that have to be typically overcome to successfully implement flow technology in a medical application.

Differential Pressure Flow Meters – Reliability:

In many medical scenario’s a first challenge to overcome is to demonstrate long term reliability and performance. Proving that your meters have a multi-year life cycle with no significant degradation in performance is demanding. One recent medical application required a 4 year life cycle so the customer purchased ten of the meters and subjected them to an accelerated life test. They then returned the meters to Titan for calibration comparisons. Five of the meters had not changed in performance significantly, two had shifted slightly. The other three had changed calibration by between 0.5 and 1.5% well within the customer specified requirements for their medical products lifetime. The customer then informed us that they had only subjected half the meters to the test and retained the other 5 unused as a reference.

This is typical of the caution medical equipment manufacturers exercise and demonstrates the due diligence taken by the engineers specifying for these applications. The product must be dependable even with these relatively low cost flowmeter components where the specified accuracy is only ±1.5% of full scale.

Differential Pressure Flow Meters – Customisation:

once performance and reliability is demonstrated – manufacturers often ask for a custom version of the flowmeter optimised to fit their medical device. In the above example – Titan invested in a new tool specifically for this customer to produce a meter with the same hose fitting connection they were using throughout their device. Simplifying the production process through this tooling investment reduced the long term assembly costs, important in a competitive marketplace where thousands of units are purchased each year. To make the wiring simple as well the meter has a precise cable length with a customer specified electrical socket.

Differential Pressure Flow Meters – Sterile applications:

We have licensed our Atrato® ultrasonic flowmeter technology for one high volume medical application where the sensors are used for bolus (injection) measurement and therefore have to be manufactured in clean rooms and sealed in sterilised packaging. We do not have these facilities so licensing was a pragmatic solution which suited both parties. We are currently working on low flow clamp-on systems so that our meters can be used external to fluids in contact with the body and therefore not require the same level of sterilisation.

Differential Pressure Flow Meters – Electrical integrity:

Any piece of medical equipment has to withstand electrical interference without compromising the function of the unit. Flowmeter sensors must have excellent noise immunity so no false readings are made.

differential pressure flow meters

To discuss your medical flow metering application with Titan Enterprises please contact us here.