Not directed at you. I also know how trade mags are written - most articles are written by people that make money off their point of view. However in almost all threads you respond to you push your product. But that's not advertising.
Many years ago I was trying to solve the problem of my customers cycling their pumps to death. I started with VFD’s, and studied electrical engineering. Back then everyone used a valve as a backup for the VFD, which gave me a lot of experience with both. It soon became obvious that these systems were running on the control valves a lot of the time, as that is what happens when the VFD stops working. Even today that is what happens. The “safeguards” for when a pressure transducer or VFD fails is a common pressure relief valve, which is simple and reliable, mostly because it is completely mechanical.
Because of all the problems I was having with VFD’s, the CSV was designed to mimic the constant pressure delivery of a VFD. We called it a Cycle Stop Valve because we thought that was all it did. However, it didn’t take long to discover that eliminating pump cycling also solved about 90% of all other pump system problems. So now when someone mentions failures with check valves, bladder tanks, pressure switches, contactors, broken pipes, etc., I explain that cycling is the real cause of those problems. When the pump keeps coming unscrewed, chaffing the drop wire, banging against the casing, causing water hammer, etc., the real cause of the problem is cycling. Cycling can even be attributed to sediment and other stuff, as not only is the pump cycling, but the well is cycling (surging) also. And yes we still replace a lot of VFD’s. Anytime an owner gets tired of trying to mitigate all the problems of VFD’s, it is replaced with a CSV.
So it is very hard to help with any pump system problems and not mention the CSV, as it actually solves most of those problems. You can’t help someone with a headache and not mention the remedy.
But I set up and maintained hundreds of VFD based distribution systems for municipalities all over the southeast and they by far rather VFDs to any sort of valving. Pressure transducer failure is not very common and there are often safeguards for that. Most utilities were thrilled to get rid of any kind of mechanical flow/pressure controls. Much easier and no pipeline disturbances to replace a VFD or sensor.
You are exactly right about that. But that is because nobody knows or wants to know anything about pumps or anything anymore. If there isn’t a color display to tell them what the problem is, and if they can’t fix it by pushing a few buttons, they are lost. The few people in this world still alive that really understand pumps know that CSV’s are much better for pumps than VFD’s. But most people, including many pump contractors, can’t change a simple pressure gauge unless they have an app for it. One little EMP and we are doomed. There just aren’t any people around anymore that can keep and engine or a pump running with a little Duct Tape and some Bailing Wire.
“Much easier” doesn’t make it right. Quality, longevity, and even common sense are usually sacrificed for easy.