Industrial Electrical Controls

I got involved in a project and would like to modify an existing control cabinet on an Ultrafitration system. Currently, the system operates 24 hours a day as it requires an operator to adjust valves to set operating pressures as it starts and stops to avoid shocking the membranes. I would like to install soft starters so the two pump drives involved will ramp up and down at start and stop. That way, the valves can be pre set at operating pressure and no operator is needed. It currently discharges until the tank meets a set level and then a valve stops the discharge and returns the clean permeate to the process tank. I can use that signal to start and stop the system autonomously and save a bundle of electricity. I'm guessing it's about $150-200 a day to operate the 20 and 60 HP pumps, if I can put this bitch to sleep when it doesn't need to discharge I think I can save about half of that. Can I size the soft starters from the existing starters or do I need some wizard form MIT to make a choice?

I think the ability to ramp up or down would have to be built into the motors driving the pumps.

Nope, I had two of these systems. I put VFDs on them without issue. The VFDs are $5K, and I don't need all that it gives me. The VFD will require more space/cabinet protection, wire and labor. Not what I want, soft start for $500-600 does what I want and fits in existing control cabinet, simple/done/cheap.

I ran into a similar situation a few years back but solved it with a different approach.
Rather than utilize a soft start or a vfd, I installed a 4" motorized three way ball valve with a spring loaded return in the supply line feeding the bank of ultrafilters.

When the pumps were shut off the valve returned to rest position. When the pump started, the valve was actuated and the permeate bypassed the ultrafilters and returned to the tank. As the valve slowly opened, it gradually diverted the flow to the ultrafilters eliminating the initial shock.

Not sure if something like this will work in your application. Mine was on an E- Coat line.

Paulie

That isn't going to work in this system. These membranes are sensitive to shock. I did this years ago on another identical system with VFDs. I had operational differences in the process that required speed control in that application, this does not. By any chance was this Ecoat a wide channel KOCH system?

This was on a Jessup line. We modified the ultrafilter rack for pretty much the same reason that being to eliminate the initial shock on the membranes during startup.
The motorized valves are ramped up and down thru the plc.

I just did something very similar on a TTX line to control the boiler water input flow on the Zinc Phosphate heat exchanger.

The original design called for a vfd on the Zinc Phosphate pump to control the initial high boiler temperature shock on the heat exchanger.

Paulie

I just want a control to ramp the motor speed up and down. No other changes to the controls or physically to the system itself. I just spoke with a pal on another forum who sells VFDs and soft starts, looks like he can help me out but his prices are double what I've seen on the web. His product is Toshiba and I have zero experience with that brand. Warranty is 18 months, up there with the other good brands though.

I've seen a lot of Toshiba's out there, and never heard anything bad about them nor do I see any red flags or complaints online.

I just did a quick search and they also seem to be priced in line with the other manufacturers as well as being competive in price to a motorized ball valve.

Good luck with your project, and keep us posted !

Paulie




Paulie

It already has a valve. When finished proccesing, the valve operates at a set level and returns the clean permeate to the dirty process tank and runs all night. That's the problem, it running all night doing nothing at 80 HP. With the soft start, it can ramp up and down to stop and start without a human operator to adjust the valves. By using the same level control that operates the valve, I can control the machine with the tanks level autonomously as prodution warrants.

Is this on an E- Coat line ?

Paulie

No, it is a wastewater application.

coaledsweat wrote: ↑

Sun. Dec. 03, 2017 11:37 pm

No, it is a wastewater application.

Industrial or Municipal ?

Paulie

It's a commercial laundry that does linen and dust control products. Not a really dirty stream like industrial which would have a lot of oil, solvents and grease that I'm familiar with. The process design and operation is the mess, not the waste stream.