Hey, I need the right flow meter - one with at least 0.75 percent accuracy - for an application. Could you help us? The pipe is 1" and the product is diesel, with the maximum temperature 40C, pressure 6 kg/cm2, and flow 3 m3/hr. We're using analog communication. Any ideas?
Expert’s answer: Diesel flow meter
To measure your diesel flow properly, we need not only your process data but also your expectations for the process. We have some content here at Visaya that covers how to size a new flow meter. You can also find several tools from different brands that can support you in this task. But we’ll get you started.
To dig up some good options, I chose a couple of common tools. Emerson’s Toolkit needs you to download and install the software. That part sucks, but otherwise it’s a good tool. And Endress+Hauser’s Applicator lets you size a new device online without installing anything. Obviously, I prefer that, but your mileage may vary.
Okay, now let’s lay out your process data:
- Product: diesel
- Pipe diameter: one inch
- Communication: analog
- Maximum process temperature: 40 degrees Celsius
- Maximum process pressure: six kilograms per square centimeter
- Measuring range: zero to three cubic meters per hour
Based on those specs, I found two solutions for your application, ultrasonic flow meters or Coriolis flow meters. So let’s go over the pros and cons of each.
The ultrasonic or volumetric meter gives you the better cost-benefit. Also, it won’t create a pressure loss because it doesn’t need a restriction in the tube. Based on your process data, you should get an accuracy of 0.5 percent on your one-inch pipe, plenty for your needs.
For the cons, you can’t use it in a liquid with a high particle content, because that can affect the measurement. Plus, you’ll need minimum inlet and outlet runs, which may limit its placement.
On the other side, the Coriolis mass flow meter provides much better accuracy – a whopping 0.25 percent in your process! – and needs no minimum inlet and outlet run. You also get volumetric flow, mass flow, density, and temperature all in one device.
However, it does create pressure loss, so you need to make sure your process can support that. And it costs more than the ultrasonic.
We based this study on the low-end options from Emerson and Endress+Hauser. If you want to shell out more, then you might find a device with extra options to enjoy. Hope this at least gets you started!