Yesterday I covered flow rate and reference conditions and talked about how important (or not) these are to specifying a variable area (VA) flow meter. Today, I’ll finish up my tips by reviewing fluid density and viscosity as well as accuracy.
Fluid: Density and viscosity
We always have questions about the fluid such as gas or liquid. What are the density and viscosity? Is it corrosive or opaque? If it a know fluid such as air, nitrogen, water, etc. The questions get much easier because the world has defined how these known fluids behave so we can easily determine density and viscosity for common fluids such as air, water, nitrogen, etc. Which leads to the questions as to why do we need to know fluid density and viscosity? Fluid density and viscosity are important because these two values allow us to select the right flow meter (meter size). We call this sizing. What is behind sizing? Briefly, performance data has been collected on all of the different meters we offer. We query the performance data and look for flow meters that fit the supplied process conditions (density and viscosity). Usually there are many flow meters that fit your conditions. From there it becomes a matter of preference, available options, price or accuracy. This leads me to my last topic on VA meters, which is accuracy. Read more…
In yesterday’s blog post, I took you through why we need to know about your normal and maximum operating temperatures and pressures in your application to specify the right variable area (VA) flow meter for your process. Today, we’ll dive into flow rates and reference conditions.
3. Flow rate – minimum, maximum, normal
Of course flow rate is an obvious requirement but it is more complicated than it appears. The goal is to specify a VA meter where the normal operating flow is in the 60% to 80% of the meter’s range. Why you ask because a variable area meter is more accurate in the upper part of its range. I will talk more about accuracy in my next blog post. Of course a flow meter needs to be chosen that handles the minimum and maximum flows too. The other component of flow rate is the units. Read more…
Categories: Variable Area/Purge Meters Tags: flow meter, flow meters, va flow meter, va flow meters, va meter, va meters, variable area, variable area flow meter, variable area flow meters, variable area meter, variable area meters
Variable area (VA) flow meters will respond like the canary in the mine when the air quality changes. If process conditions change there usually is an impact on flow rate. For example if back pressure changes on gas flows the float/flow will change just as changes in liquid viscosity will have a similar impact to the float/flow.
VA meters reacting to changes in process conditions can be a good or bad thing based on a user’s viewpoint, which brings us back to the real question. So why do we need so much information to specify the proper VA meter? I will go through the questions and explain why it is necessary. The information needed is: Read more…
I thought this short application success story was worth sharing!
A major chemical company was looking for an economical solution to purging cabinets that are used in Division 2 hazardous areas. Division 2 locations are areas where hazardous gases are only present under abnormal conditions. The customer has been using a Z Purge System, which not only purges the cabinet but maintains a positive pressure in the cabinet. The positive pressure keeps the hazardous gases from entering the cabinet where a spark could cause an explosion. The economical solution tested by the customer was a model 2510 plastic tube flow meter. The model 2510 variable area flow meter flows a known volume of purge gas into the cabinet which maintains a positive pressure. A flow meter is not the answer for every customer but it worked for this one!
Do you have a similar application? Let us know.
I’m really excited to announce the availability of a low flow rate option for our Model MT3809 armored rotameters. The MT3809 variable area flow meter is now capable of accurately measuring flow rates as low as 5 L/h of air and 0.08 L/h of water with this new option. We’ve had customers requesting this new option but the real advantage is that we now have HART communications for a low flow armored flow meter. Read more…
Categories: Variable Area/Purge Meters Tags: chemical, engineering applications, flanged meters, flow accuracy, flow meter, flowmeter, HART communications, petrochemical, rotameter, rotameters, variable area flow meter, variable area flow meters, variable area meter
It’s official! We have received our important CSA and CRN approvals for the Model 810 magnetic level gauge and associated transmitters and switches. These approvals verify Brooks’ high quality and compliance with international standards that customer’s value.
CSA International, the leading provider of product testing and certification services for the United States and Canada, has certified Brooks transmitters and switches to be intrinsically safe and explosion/flame-proof in Class I, Div 1 hazardous areas. ABSA (Alberta Boilers Safety Association), the pressure equipment safety authority for Alberta, Canada, has also issued a CRN (Canadian Registration Number) certificate for the Model 810 magnetic level gauge. Brooks expects to receive CRN certificates for the rest of the Canadian provinces shortly.
The CSA and CRN certificates are just two more in our very broad international certification portfolio, including IECEx, ATEX, EDF’s K3 nuclear certifications, PED and many more, allowing us to meet a broad set of customers’ requirements throughout the world and in many industries.
We are focusing on improving our order fulfillment process because we know it will result in faster lead times and more satisfied customers. I want to provide a “peek” into our lean manufacturing journey, share my personal experiences and include a photo or two of our rotameter assembly lines.
The improvement process starts by defining in great detail how we do things today. It is difficult to change a process without totally understanding what you are doing today. Once this first step is completed a cross functional team reviews each step of the process and as a group looks for areas of improvement. I have participated in these group sessions and they are very powerful due to the free exchange of ideas. Each suggestion is noted, debated and usually implemented. Possible ideas can be as simple as organizing the workspace which reduces operator movement and “travel time” to adding new test equipment or assembly fixtures.
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When I was a process engineer, I did not have the time nor the money to try and explore new technologies. I wanted something that was proven, worked well and did not give me headaches. In an industrial production environment, unlike R&D, no one wants to be the guinea pig. A production line depends on the decision you take. Therefore, it is important to have the necessary information at your finger tips to help you make that critical decision.
I have to tell you that it is really confusing out there. Every company tries to spin its own product as the best solution since sliced bread. In reality, we all want an unbiased knowledge database to learn from and refer to when we need help. I hope this blog is a start of a discussion to build our knowledge of fluid level measurement.
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A rotameter (variable area meter) is a flow meter that measures volumetric flow of liquids and gases. The technique for measuring flow is accomplished by a freely moving float finding equilibrium in a tapered tube. The flow rate is then read from either a scale next to the tube or a scale on the tube.
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