Auto-sparge via liquid level sensor on site glass - Project

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Sparky

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Just started this build and hope to get some input on the design, mainly need to make sure I have the right relay (see schematic).

Background
I typically take 45-60min for a 5 gallon batch to sparge and up to 2 hours for bigger batches. Adjusting the input/output of the sparge is tedious - I have better things to do than constantly tweeking the valves during this phase. I wanted to build an auto sparge system with the following requirements:

- Non-penetrating of kettle
- Measurement system that will not be in the mash kettle (cleaning, contamination, clogging)
- Easy adjustments
- Reasonably priced components

Solution
For the reasons mentioned above, I wanted to avoid the Blichman auto-sparge and general float switches.
I noticed on HBT that someone mentioned Omron had a site level sensor, but subsequent messages on HBT yielded no results of someone actually doing a build.

However, I was able to find the liquid level sensor from Omron (picture below):
http://www.ia.omron.com/products/family/475/
I have a Blichman 20gal tank and was able to remove the outer (metal) measurement guide. The site glass is 15mm so the E2K-L26MC1 was the appropriate size. These sensors are a NO operation mode. The premise is that they will turn on/off the pump, based on the level of liquid in the site glass. They are easily attached via small zip tie and can be slid up/down the site glass. They can be attached with a separation of >1 3/8" (>35mm), which is perfect for a liquid level bed.

Wiring
See the attached wiring diagram below. I am not sure about the correct relay since I cannot find a wiring diagram of one.
I will be controlling the pump on/off via the two sensors. The relay will be able to handle 120V output so an SSR is not needed.
If someone could help out with the appropriate relay, that would be great.

Cost
(2) used Omron E2K-L26MC1 = $40
(1) relay/base = $25
wiring/plugs = $6
Total cost = ~$71

Photo at bottom of page is existing setup (before any mod).

Omron E2K.jpg


Auto-sparge Wiring.jpg


IMG_3342.jpg
 
Are the valves going to be at a pre-positioned level? at the full flow rate of a march pump I'm not sure how you would control cycle time.
 
Can't you use a single optical sensor to turn a single pump on/off? Similar to a mechanical float switch.

The sensors are NO activated, so would need two: one for the higher level and one for the lower level.
 
Are the valves going to be at a pre-positioned level? at the full flow rate of a march pump I'm not sure how you would control cycle time.

They can be adjusted up/down on the sight tube. The gap between the sensors will dictate the cycle time. Here is a mock-up I did on the sight tube with the sensors (NOTE: will use zip ties instead of rubber bands).

I am just waiting for someone to check if I have the correct SPDT relay.:mug:

IMG_3706.jpg


IMG_3708.jpg
 
I think you will need several additional components to create a dead band/historiesis with 2 sensors. If the mash drain and pump flow rate are pretty close then the cycle time should be pretty long.

Alternately you could cycle a solenoid valve on/off and leave the pump running.
 
I think you will need several additional components to create a dead band/historiesis with 2 sensors. If the mash drain and pump flow rate are pretty close then the cycle time should be pretty long.
Alternately you could cycle a solenoid valve on/off and leave the pump running.

JCO, thanks for your feedback.
The cycle time will be based on the separation of the two sensors. Since they are NO operated, I thought a SPDT relay would work well. It would basically toggle back and forth between on/off. The relay and sensor would be off of 12VDC to trigger the pump on/off. The relay is rated over 120V so I would run a leg through it for the pump.

I thought about doing the solenoid valve on/off, but did not want the pump spinning for that length of time.

Want to know if there is any relay experts out there to see if I spec'd the right one. It is McMaster-Carr #7266K41.
 
The McMaster-Carr #7266K41 relay is A-Ok. However I think you need to refine your wiring plan for the level switches and the way they will energize the relay.

OR - perhaps I just do not understand the wiring layout of the sensors. That (BTW) is most probable. I've not been able to find a single circuit diagram for them.

P-J
 
I love the idea of using these sensors on a sight glass! I'm not getting the logic of the wiring diagram, though. It seems like there's three possible states with the two sensors, and the desired behavior is:
1. Water below both sensors --> Sparge pump should be on
2. Water above both sensors --> Sparge pump should be off
3. Water between the sensors:
--> Sparge pump should be on if last state was (1)
--> Sparge pump should be off if last state was (2)

In your diagram it looks like you're planning to wire the switches in parallel, so the pump relay is engaged whenever either switch senses fluid. Is that right? If so, it wouldn't give you the history dependent behavior you're wanting in state (3). In fact, I think your pump just be off in state (1) and on in state (2) or (3).

But I'm new to electronics, so take this all with a grain of salt.

EDIT: Ignore me (the electronics newbie) -- P-J is on the case!
 
OR - perhaps I just do not understand the wiring layout of the sensors. I've not been able to find a single circuit diagram for them.
P-J

P-J, thanks for the feedback (sorry about the PM)! I've attached the spec sheet for the sensors below. It is NO operation mode with power on the input to the sensor and power on the output to trigger the SPDT relay. Or, that is the hope!

View attachment Liquid Level Sensor.pdf
 
I love the idea of using these sensors on a sight glass! I'm not getting the logic of the wiring diagram, though. It seems like there's three possible states with the two sensors, and the desired behavior is:
1. Water below both sensors --> Sparge pump should be on
2. Water above both sensors --> Sparge pump should be off
3. Water between the sensors:
--> Sparge pump should be on if last state was (1)
--> Sparge pump should be off if last state was (2)

In your diagram it looks like you're planning to wire the switches in parallel, so the pump relay is engaged whenever either switch senses fluid. Is that right? If so, it wouldn't give you the history dependent behavior you're wanting in state (3). In fact, I think your pump just be off in state (1) and on in state (2) or (3).

But I'm new to electronics, so take this all with a grain of salt.

EDIT: Ignore me (the electronics newbie) -- P-J is on the case!

NO No no....

All input within these threads is very valuable.

You pointed out some of my exact concerns. That is extremely important. I'm just one person and I do make mistakes in observations and in some of my thinking. As I've said many times before - "Getting old just plainly sucks!"

P-J
 
All input within these threads is very valuable.
P-J

Agree 100%, thanks tophmck & P-J for feedback. Hell, I have a BSEE and run an electrical/photovoltaic contracting company, but scratch my head on some of this stuff.

My thinking is that since the sensors are NO operation, I would use two so they could toggle the relay (SPDT) and trigger the pump on/off.
 
I think you might be able to use a dpdt relay to latch the relay on (pump off) at your max level and reset when you go below the min level sensor. Spdt will work with a single sensor and simple on/off mode.
 
jCOSbrew said:
I think you might be able to use a dpdt relay to latch the relay on (pump off) at your max level and reset when you go below the min level sensor. Spdt will work with a single sensor and simple on/off mode.

DPDT relay with pump 110v on one set of NC contacts.

High level switch will energize 12v relay coil

2nd set of contacts will latch relay on by connecting 12v from NO to relay coil.

Low level switch will break the 12v feedback/latch when liquid drops below low level.

Use a 3-way switch to allow on/off/sarge modes for the pump.
 
Ahhh, I was in the thought pattern of toggling back/forth the switch on DP.
Based on your input it would be:
http://www.mcmaster.com/#catalog/118/906/=kv9kn0
McMaster-Carr part #7266K43 which is a Spade-Terminal Relay DPDT, 12 DC Control Voltage via those sensors and pipe through 120V for the pump.

Already have the 3-way switch for the pump for on/auto settings;).
 
OK, I promise not to censor myself, P-J. :)

This seems like a really elegant solution, jCOSbrew. Can't wait to see how well these sensors work!
 
This looks like a very good solution for sparging. One concern that I have is that there is flow through a pump even if it isn't running when there is a height differential in the liquid levels. Using the control for a solenoid valve and keeping the pump running continuously might be a better solution.
 
The relay arrived today, so time to tinker.
Sheesh, no wiring diagram for the relay. Damn, something else to figure out (cryptic drawing on side of relay is murky).

Relay.jpg
 
thinking about it you could use this for an auto sparge. by just putting the floats on a adjustable pole on top of the mash.

it actually works quite well in the Areogarden keeping the level topped up to the exact setting you set it.

The bottom float turns on the pump when it gets low, and the upper float is only there as a fail safe in case the bottom float fails.

While watching the one in the Areogarden it only turned on for a few seconds at at time.

i dont actually like the way they wired there project box and made my own wiring in a larger project box which included a a on /off switch and a hot and switched socket which you plug the 12 volt transformer and the pump
 
Okay, so I'm back after a hiatus (had to get the company $$ pipeline filled).
Anyway, brewed last weekend and got psyched about reviving this project since I do have all the parts. Hell, they've been sitting in a box for a year!

Gonna wire this up and see if it works! Check out my wiring diagram.
Moo-hoo-ha-ha.

Relay wiring - site.jpg
 
Nice revive. I've wondered about this. Sub'd in hopes of an update.
 
I did this very successfully for a while using these exact sensors. In fact, I have two available for purchase if anyone wants.

You really don't need two to perform the AS. One has enough hysteresis that you can control your outflow pump from that alone, because you are going to drain off slowly. For manual value users, set your outgoing valve slightly more open than your incoming one, then the AS will cycle the pump as needed to maintain the fluid level.
 
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