Variable Speed March Pump

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Question:

WoW, hehehe. The core temp, that IS freaky. Just curious, are you going to have a graphical interface for it? If I had that kind of money in it, graphical interface would be a must. Something like a flat panel monitor? Have fun, Tom Meier Wrencoe, TN

Response:

HX stands for Heat Exchanger. The general layout will be: Outlet from pump into 3-way valve with outlet1 going into HERM HX and outlet2 going back to the mash. The general idea is to modulate the valve and send just the right amount of run-off thru the HX to pick up some heat and reintroduce this back to the mash, thereby keeping the mash at a specific temperature.

How are you supplying heat to the HX ? DB

Response:

Well then, at 160F or below, you’re probably ok. You’ll have to heat the whole mass to mashout, which will take a bit longer, but probably not that much. Assuming you’re going to mashout. I assume you’re still going to strike so that you’re close to your first rest. If the rest is at 156F, you won’t get much heating rate if the HLT is at 160F. Some, but not a lot. Regards, Mike Sharp

Response:

- Hide quoted text — Show quoted text – HX stands for Heat Exchanger. The general layout will be: Outlet from pump into 3-way valve with outlet1 going into HERM HX and outlet2 going back to the mash. The general idea is to modulate the valve and send just the right amount of run-off thru the HX to pick up some heat and reintroduce this back to the mash, thereby keeping the mash at a specific temperature. That sounds like a better idea. Controlling the pump could get ugly. Those march pump motors are not invertor duty rated, but then again, they don’t see alot of duty. Still, a couple of hours at low speed might be enough to fry one.

True, but centrifugal pumps (especially ones with open impellers like this one) fall off dramatically as speed drops. I don’t think you’d ever have to run it down to 30 hz, which should still be fast enough for cooling. Probably never get below 45hz. Regards, Mike

Response:

A CFC would work great for that. Somebody else here uses an old corny with the top cut off but I would think that the CFC would provide better response for use with a PID controller. You know, I haven’t spent much money on my brewery lately! Maybe it’s time for an upgrade? Nope. It’s brewing time. I usually tinker in the summer when I’m too busy to brew. Burp, -Dan — Replace nospam with msn to email me.

– Hide quoted text — Show quoted text – I’m still wondering if that won’t denature too many enzymes, since the temperature of the wort exiting the coil will essentially be 170F, or whatever your HLT temp is…be sure to let us know how it works. That’s my concern too. It MAY be OK because you’re only recirculating through the HLT for short periods of time to maintain the mash temp. The rest of the time you either 1) stop the recirculation or 2) shunt the wort flow to by-pass the HLT. In either case, it can’t help and must do some harm – but possibly not enough harm to matter, if done properly. In his case, he’s circulating full time, but decreasing the rate through the HLT, and increasing the rate through the bypass. At steady state the flow rate through the HLT might be slow enough to give a long contact time at 170. That’s why I was considering an external heat exchanger where you could control the HLT flow. When it’s throttled back, the temp in the heat exchanger would be essentially the mash temp, plus a degree or two, to offset heat losses. But maybe there’s enough mash volume that it doesn’t matter. Regards, Mike Sharp

Response:

I’m not gonna hurt a single one of them beauties, the HX is a separate tank (5 gallon pot that came with the turkey fryer) that has a water heater element stuck in the bottom. The wort will flow through it’s own coil immersed in the heated water, probably at 155F to 160F. Peter – Hide quoted text — Show quoted text – HX stands for Heat Exchanger. The general layout will be: Outlet from pump into 3-way valve with outlet1 going into HERM HX and outlet2 going back to the mash. The general idea is to modulate the valve and send just the right amount of run-off thru the HX to pick up some heat and reintroduce this back to the mash, thereby keeping the mash at a specific temperature. I’m still wondering if that won’t denature too many enzymes, since the temperature of the wort exiting the coil will essentially be 170F, or whatever your HLT temp is…be sure to let us know how it works. Regards, Mike Sharp

Response:

There will be an RTD in the outlet flow from the HX. If fact there will be RTDs everywhere: HX inlet, HX outlet and the HX core. I’ll be controlling the core temp, I’ll be controlling everything, I’m a control freak! Sounds like you’re an HVAC person also, I’m with JCI. Peter – Hide quoted text — Show quoted text – That sounds like a better idea. Controlling the pump could get ugly. Those march pump motors are not invertor duty rated, but then again, they don’t see alot of duty. Still, a couple of hours at low speed might be enough to fry one. In HVAC applications, a 3-way is used on the outlet of the heat exchanger so that it receives two input flows, the bypass flow, and the flow exiting the heat exchanger. The bypass has a valve which is set such that the flow restriction of the valve is the same as the flow restriction of the heat exchanger. This way, if the 3-way valve is 0% bypass or 100% bypass, the pump still sees the same amount of flow restriction. It makes for a very controllable system, and the 3-way valve ensures thermal mixing. You will probably need a bare thermocouple or RTD to get a fast response time. Good luck and have fun, Tom Meier Wrencoe, TN

Response:

I’m still wondering if that won’t denature too many enzymes, since the temperature of the wort exiting the coil will essentially be 170F, or whatever your HLT temp is…be sure to let us know how it works. That’s my concern too. It MAY be OK because you’re only recirculating through the HLT for short periods of time to maintain the mash temp. The rest of the time you either 1) stop the recirculation or 2) shunt the wort flow to by-pass the HLT. In either case, it can’t help and must do some harm – but possibly not enough harm to matter, if done properly.

In his case, he’s circulating full time, but decreasing the rate through the HLT, and increasing the rate through the bypass. At steady state the flow rate through the HLT might be slow enough to give a long contact time at 170. That’s why I was considering an external heat exchanger where you could control the HLT flow. When it’s throttled back, the temp in the heat exchanger would be essentially the mash temp, plus a degree or two, to offset heat losses. But maybe there’s enough mash volume that it doesn’t matter. Regards, Mike Sharp

Response:

That’s my concern too. It MAY be OK because you’re only recirculating through the HLT for short periods of time to maintain the mash temp. The rest of the time you either 1) stop the recirculation or 2) shunt the wort flow to by-pass the HLT. In either case, it can’t help and must do some harm – but possibly not enough harm to matter, if done properly. Tony V. http://home.attbi.com/~verhulst/RIMS/rims.htm

Response:

Thanks. Makes sense now. Medford, NY swap net.optonline to reply via e-mail

Response:

Hi All, Has anyone applied a ‘Variable Speed’ control to a March pump? I’d like to do this for my upcoming HERM system.

It’s my understanding that you don’t want to control the output speed of a pump by varying the power you send to it with a "dimmer" type switch. It’s supposed to be bad for the motor. You want to be running the pump with 120v all the time. The way you adjust the flow is to put a valve on the output side of the pump. John. — *** John P. Kolesar *** *** Valley Mead Brewery ***

Response:

That sounds like a better idea. Controlling the pump could get ugly. Those march pump motors are not invertor duty rated, but then again, they don’t see alot of duty. Still, a couple of hours at low speed might be enough to fry one. In HVAC applications, a 3-way is used on the outlet of the heat exchanger so that it receives two input flows, the bypass flow, and the flow exiting the heat exchanger. The bypass has a valve which is set such that the flow restriction of the valve is the same as the flow restriction of the heat exchanger. This way, if the 3-way valve is 0% bypass or 100% bypass, the pump still sees the same amount of flow restriction. It makes for a very controllable system, and the 3-way valve ensures thermal mixing. You will probably need a bare thermocouple or RTD to get a fast response time. Good luck and have fun, Tom Meier Wrencoe, TN

Response:

- Hide quoted text — Show quoted text – Wow Mike, Thanks!!! For now I’m probably gonna go with a 115vac constant speed pump, push the wort thru a separate HX with a bypass thru a controlled 3-way valve and back to the mash tun. Later on I might try something else. As an aside, I work for Johnson Controls and have an endless supply of controllers, valves….. so I’m gonna try everything. To Peter: Most PID controllers I’ve seen won’t provide enough power for a pump, and their output is typically an analog control signal, or a time domain proportioned pulse train. How are you going to drive the pump? Now, you can get AC or DC speed controls, but there’s no practical difference from the PID controller’s point of view. The cheapest way would be to use a 110vdc pump, and one of the cheap Dart DC speed controls. Control the speed controller using the PID controller DCV output (whatever it happens to be), scaled correctly. However, there are some very inexpensive (compared to recent history) AC inverter drives these days. To DB: Sure, why not? I’ve done PID control of pumps on everything from a bottling line with 2 hp pump to a wastewater treatement plant with 400 hp pumps. The PID controller provides a signal to a variable frequency drive. So, the drive is set up to control speed based on, for example, a 4-20 mA signal from the PID controller. The feedback for the drive is built in to the drive. If you wanted precise metering of a positive displacement pump, or wanted to control the position of a motor, then yes, you’d need a feedback loop on the motor itself. But for centrifugal pumps, it doesn’t really matter all that much. Direct feedback for PID control is based on some process variable, usually flow or pressure, depending on your needs. In mashing, it would be based on temperature, and would be reverse control (rising temperature decreases flow). But if it’s wort flow we’re talking about, when flow is low at a rest temp, won’t you denature the enzymes? If the wort flow through my HLT is very slow, what comes out of the coil will be denatured, right? Regards, Mike Sharp

Peter, Just trying to get a better understanding here. The constant output of your pump will go to a valve with one inlet and two outlets. Your controller will adjust the ratio between the two outlets. X will go to the mash and 1-X will be fed back to the inlet of the pump. That’s a question BTW. What’s an HX? Medford, NY swap net.optonline to reply via e-mail

Response:

Wow Mike, Thanks!!! For now I’m probably gonna go with a 115vac constant speed pump, push the wort thru a separate HX with a bypass thru a controlled 3-way valve and back to the mash tun. Later on I might try something else. As an aside, I work for Johnson Controls and have an endless supply of controllers, valves….. so I’m gonna try everything.

– Hide quoted text — Show quoted text – To Peter: Most PID controllers I’ve seen won’t provide enough power for a pump, and their output is typically an analog control signal, or a time domain proportioned pulse train. How are you going to drive the pump? Now, you can get AC or DC speed controls, but there’s no practical difference from the PID controller’s point of view. The cheapest way would be to use a 110vdc pump, and one of the cheap Dart DC speed controls. Control the speed controller using the PID controller DCV output (whatever it happens to be), scaled correctly. However, there are some very inexpensive (compared to recent history) AC inverter drives these days. To DB: Sure, why not? I’ve done PID control of pumps on everything from a bottling line with 2 hp pump to a wastewater treatement plant with 400 hp pumps. The PID controller provides a signal to a variable frequency drive. So, the drive is set up to control speed based on, for example, a 4-20 mA signal from the PID controller. The feedback for the drive is built in to the drive. If you wanted precise metering of a positive displacement pump, or wanted to control the position of a motor, then yes, you’d need a feedback loop on the motor itself. But for centrifugal pumps, it doesn’t really matter all that much. Direct feedback for PID control is based on some process variable, usually flow or pressure, depending on your needs. In mashing, it would be based on temperature, and would be reverse control (rising temperature decreases flow). But if it’s wort flow we’re talking about, when flow is low at a rest temp, won’t you denature the enzymes? If the wort flow through my HLT is very slow, what comes out of the coil will be denatured, right? Regards, Mike Sharp

Response:

– Hide quoted text — Show quoted text – Wow Mike, Thanks!!! For now I’m probably gonna go with a 115vac constant speed pump, push the wort thru a separate HX with a bypass thru a controlled 3-way valve and back to the mash tun. Later on I might try something else. As an aside, I work for Johnson Controls and have an endless supply of controllers, valves….. so I’m gonna try everything. Peter, Just trying to get a better understanding here. The constant output of your pump will go to a valve with one inlet and two outlets. Your controller will adjust the ratio between the two outlets. X will go to the mash and 1-X will be fed back to the inlet of the pump. That’s a question BTW. What’s an HX? Medford, NY swap net.optonline to reply via e-mail

Response:

Found a new way to go also… March makes 24v DC pumps. They cost a bit more but can be controlled precicly with a PID controller.

– Hide quoted text — Show quoted text – Hi All, Has anyone applied a ‘Variable Speed’ control to a March pump? I’d like to do this for my upcoming HERM system. Peter

Response:

Found a new way to go also… March makes 24v DC pumps. They cost a bit more but can be controlled precicly with a PID controller. Hi All, Has anyone applied a ‘Variable Speed’ control to a March pump? I’d like to do this for my upcoming HERM system. Peter

A PID controller for a pump? Would you not need to somehow measure the pump’s output and convert that into an electrical signal for feedback? Or maybe you don’t use it in PID mode and just manually adjust the voltage? Seems like a bit of overkill no? I do prefer to control the pump instead of just restricting the output. It keeps pressure down reducing the risk of a hose popping off and also the pump has less work to do. DB

Response:

This will be for a HERM system, so I’ll probably be measuring the outlet temp of the mash before sending it back to the mash tun. I’ll vary the pump speed to get the ideal temp. I might go with a fixed speed pump and an electric actuated 3-way valve on the heat exchanger instead. I’m still in the ‘Who knows what I’ll do’ stage. Peter – Hide quoted text — Show quoted text – Found a new way to go also… March makes 24v DC pumps. They cost a bit more but can be controlled precicly with a PID controller. A PID controller for a pump? Would you not need to somehow measure the pump’s output and convert that into an electrical signal for feedback? Or maybe you don’t use it in PID mode and just manually adjust the voltage? Seems like a bit of overkill no? I do prefer to control the pump instead of just restricting the output. It keeps pressure down reducing the risk of a hose popping off and also the pump has less work to do. DB

Response:

Found a new way to go also… March makes 24v DC pumps. They cost a bit more but can be controlled precicly with a PID controller. A PID controller for a pump? Would you not need to somehow measure the pump’s output and convert that into an electrical signal for feedback? Or maybe you don’t use it in PID mode and just manually adjust the voltage? Seems like a bit of overkill no? I do prefer to control the pump instead of just restricting the output. It keeps pressure down reducing the risk of a hose popping off and also the pump has less work to do. DB

To Peter: Most PID controllers I’ve seen won’t provide enough power for a pump, and their output is typically an analog control signal, or a time domain proportioned pulse train. How are you going to drive the pump? Now, you can get AC or DC speed controls, but there’s no practical difference from the PID controller’s point of view. The cheapest way would be to use a 110vdc pump, and one of the cheap Dart DC speed controls. Control the speed controller using the PID controller DCV output (whatever it happens to be), scaled correctly. However, there are some very inexpensive (compared to recent history) AC inverter drives these days. To DB: Sure, why not? I’ve done PID control of pumps on everything from a bottling line with 2 hp pump to a wastewater treatement plant with 400 hp pumps. The PID controller provides a signal to a variable frequency drive. So, the drive is set up to control speed based on, for example, a 4-20 mA signal from the PID controller. The feedback for the drive is built in to the drive. If you wanted precise metering of a positive displacement pump, or wanted to control the position of a motor, then yes, you’d need a feedback loop on the motor itself. But for centrifugal pumps, it doesn’t really matter all that much. Direct feedback for PID control is based on some process variable, usually flow or pressure, depending on your needs. In mashing, it would be based on temperature, and would be reverse control (rising temperature decreases flow). But if it’s wort flow we’re talking about, when flow is low at a rest temp, won’t you denature the enzymes? If the wort flow through my HLT is very slow, what comes out of the coil will be denatured, right? Regards, Mike Sharp

Response:

Hi All, Has anyone applied a ‘Variable Speed’ control to a March pump? I’d like to do this for my upcoming HERM system. Peter

Response:

Hi All, Has anyone applied a ‘Variable Speed’ control to a March pump? I’d like to do this for my upcoming HERM system. Peter

I got a ceiling fan speed controller (not a light dimmer… that’s a different animal) from Home Depot for about $8 and connected it to a standard outlet. Both fit nicely into a 4×4 metal box (the kind that outlets and switches go into in the wall of homes). One romex connector and a line cord completed the project. I used a one switch/one outlet cover and the controller stem sticks out thru where the switch normally would. I use this to control my mag drive recirculating pump. It behaves a bit oddly… it hardly provides any control at all unless I partially pinch off the pump’s outlet hose. But once I do that I can precisely control the flow over quote a wide range of flow rates. Partially pinching off the outlet hose makes the pump work harder and (I’m assuming) brings the current draw into a range that the controller can deal with. So depending on your pump’s motor and how you load it, you may get different results. But the control box works great and cost about $15 to make. And it can be used to control other things when I’m not brewing like fans, routers, etc etc. DB

Response:

– **Remove the obvious when replying directly**

Hi All, Has anyone applied a ‘Variable Speed’ control to a March pump? I’d like to do this for my upcoming HERM system. Peter

I’ve heard that’s not a good idea (although I’m not an electrical kinda guy). I’m set up with my input port fully open and I adjust my speed by regulating how far open my output ball valve is set. Mike

Response:

Has anyone applied a ‘Variable Speed’ control to a March pump? I’d like to do this for my upcoming HERM system.

No need to – just use a ball valve on the outlet side and adjust it for the flow you want. cheers, -Alan

Response:

That’s how I set up my system and it works perfectly. Just be sure not to restrict the inlet side. You don’t want to run the risk of running the pump dry.

– Hide quoted text — Show quoted text – Has anyone applied a ‘Variable Speed’ control to a March pump? I’d like to do this for my upcoming HERM system. No need to – just use a ball valve on the outlet side and adjust it for the flow you want. cheers, -Alan

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