Hi RedClay
I would say that the few small valves that are sold because of forum questions, in no way justifies the time I spend answering questions. I already sell tens of thousands of these valves every year to pump installers, irrigation specialist, municipalities, green houses, tree farms, feed lots, car washes, and the list goes on. I only answer questions on forums to straighten out the misconceptions that people have about pumps, valves, and VFD's.
Pumps might as well be magic to some people, as they do not understand how they work. Even people who think they understand pumps, have incorrect conceptions about how they react to being throttled with a valve or slowed down with a VFD.
It also amazes me that very few people understand that pumps, as well as most other things, are built with "planned obsolescence" in mind. Less durable materials, including bearings, are now being used. The motors are much shorter and have less "meat" in them, than in the old days. The target design life for a pump is an average of 7 years. They are still designed for continuous duty, and will last longer if run that way, than if cycled on and off. The bearings and bushings are basically frictionless when up and running. A lot of things happen on start up to cause friction and wear, even with VFD's or soft starts. So the less number of times a pump starts, the longer it will last.
Many people, including pump engineers, will spout off about "minimum recommended flow rates". These are only "recommended", and not law. Pump men who have had to deal with low producing wells all their life, know that pumps will last a long time when throttled back to the ½ or 1 GPM that the well will produce. Especially when compared to cycling the pump on and off to extract ½ or 1 GPM from a well. It has been my experience that a pump throttled back to 1 GPM and running 24/7, will outlast a pump in a high producing well that cycles on demand, by about three times to one.
I actually started with VFD controls about 20 years ago. And yes back then they cost $5,000 and were the size of a small car. Now you can get one for a couple hundred bucks and they are only the size of a shoe box. It makes sense to most people that slowing the RPM of a pump would use less energy. It is "counter intuitive" and therefore does not make sense to most people, that choking a pump back with a valve will reduce the power consumption as much a varying the speed. This is one thing that takes someone with real pump experience to understand. Anyone who talks about valves "burning energy" and a VFD being more efficient, does not truly understand pumps. We discovered almost 20 years ago, that the valves we were using as a bypass when the VFD's failed, were just as efficient and much more reliable than the VFD.
We started out many years ago, replacing VFD's with valves, and we still replace VFD's everyday. Even though VFD's are smaller and cheaper than years ago, there are still many problems with VFD's that mother nature won't let anyone fix. Harmonics, voltage spikes, resonance vibration, low flow rates, and many other problems exist with VFD's that are not present with Valve control. Our best customers are ones who have already been through the VFD phase and like the "constant pressure" but, hated the complications and unreliable water supply from a VFD.
I predict that Bill Arden is right, that in a short time the VFD will be incorporated into the motor itself, so we don't have any choice of purchasing it or not. This is just one more way of forcing "planned obsolescence" on the public. Then we will be forced to replace our pumps as often as we replace our computers. We will be replacing our pumps every 5 to 7 years as the manufacturer likes, and the public will not even remember that pumps should last 30 years. Gone are the days of one pump system lasting multiple generations. It is impossible to save enough energy to pay for 5 or 6 pump systems, compared to having one pump system last 30 years. Of course manufactures want you to think they are doing things to save energy, when in reality, they are doing things to keep your cash flowing into their pocketbooks.
VFD's have been around for more than 30 years. During this time they have been saying that in the next few years all the bugs will be worked out. I don't think they will ever be able to get rid of all the VFD bugs. There will just come a time when we accept it, and start thinking that shelling out the bucks to replace a pump system every few years is normal. With enough money spent on marketing, we as sheep, won't even turn our heads while being led to slaughter.
