Making a Liquid Vending Machine

[ricardoxh]

Hi, I have seen a few post with similar topics and I have tried contacting the authors however I have not had any luck so I am posting this new thread.

I am looking for guidance on creating a liquid cleaning product vending machine. I’m totally new to PLC programming, I know some basic Visual Basic language and I am somewhat mechanically inclined.

I think my best way to start is learning the ladder logic and having a Rockwell PLC since I have read is the easiest for a new person like me. Also to my understanding I need a PLC that has MDB for a card reader and coin/bill acceptor. And on top of that I will need some pumps to pump the liquid and buttons to switch product.

Could I get some guidance on what parts to buy, especially I guess it will be the PLC that works with MDB. I assume the mechanical parts like buttons and pumps can be any brand and can be kind of plug and play with some programming of course. I would like the vending machine to have 3-5 different products.

 

[Steve Bailey]

Buy a used vending machine and stock it with pre-filled bottles of the cleaning product.

 

[tlf30]

I second this, especially for something like cleaning products, as prefilled bottles will prevent spills or accidental cross contamination between products that may react negatively with one another.

 

[GaryS]

Hello ricardoxh

I found you post on the PLCTALK and it looks like an interesting project
I would like to hear more about it
The one thing I is it look like a very expensive project
As was mentioned I would be better to purchase an existing vending machine and use it.
You really didn’t not give a lot of details on what you have in mind.
I have done automated carwashes. Custom blending machines, automated crane systems, complete feed mills plants actually quite a few custom automated system of all types.
If you would like to talk about it please feel free to contact me directly
Email [email protected]
Phone 717-940-9079
It cost you nothing to talk about it and we both may learn something

Regards Gary

 

[cardosocea]

I am looking for guidance on creating a liquid cleaning product vending machine.

I imagine there will be laws and standards you will have to abide by and prove your solution fulfils them when it comes to the sale of products.

 

[JesperMP]

I imagine there will be laws and standards you will have to abide by and prove your solution fulfils them when it comes to the sale of products.

+1
'Vending machine' implies that the product is provided in exchange for money.
You must either weigh or measure the volume of the product, and only bill what has been provided to the customer.
And this must be calibrated, the calibration must be sealed against tampering, and an accredited company must perform the calibration at regular intervals.
If the product expands or retracts due to temperature, then you either have to compensate for the worst case so that it benefits the customer, or you must deal with it another way.
Fuel stations actually heat the fuel (!), only so that they don't have to over-dose to the benefit of the customer when the weather is cold.
edit: Just checked up on it. Most typically gas stations have insulated tanks that can hold the temperature between fillings that it is not necessary to actively heat the tanks.

 

[cardosocea]

Fuel stations actually heat the fuel (!), only so that they don't have to over-dose to the benefit of the customer when the weather is cold.

This is somewhat scary... :/ Granted it would be just a bit of heat, but there would be some engineering around not overheating it.

edit: Just checked up on it. Most typically gas stations have insulated tanks that can hold the temperature between fillings that it is not necessary to actively heat the tanks.

I wonder if the volume of the tank is a multiple of the tanker to ensure that it can recover from a colder load being dropped in?

 

[JesperMP]

This is somewhat scary... :/ Granted it would be just a bit of heat, but there would be some engineering around not overheating it.

I once spoke to someone who had worked for a company that specialized in this. Not trivial but also not extremely difficult (*).
I think the thermal expansion of gasoline is approx. 0.1% per °C.
The gas stations sells per volume, so it pays off to keep the gasoline from cooling down in the winter. Even a small change in temperature is significant enough for it to be worth. As I understand it, in the summer the consumers are actually disadvantaged even more.

*: I think there a heating systems for fuel in other applications. I.e. for avoiding the build-up of paraffin lumps or for making it easier to pump.

 

[joseph_e2]

I once spoke to someone who had worked for a company that specialized in this. Not trivial but also not extremely difficult (*).
I think the thermal expansion of gasoline is approx. 0.1% per °C.
The gas stations sells per volume, so it pays off to keep the gasoline from cooling down in the winter. Even a small change in temperature is significant enough for it to be worth. As I understand it, in the summer the consumers are actually disadvantaged even more.

*: I think there a heating systems for fuel in other applications. I.e. for avoiding the build-up of paraffin lumps or for making it easier to pump.

Back in another life on cargo ships, we burned Heavy Fuel Oil (HFO), aka residual fuel, aka disgusting tar that was whatever was left after the "good stuff" was cracked off. The fuel tanks had heaters and the pipes were insulated and had steam tracing (steam lines around the outside of the pipes) to keep the fuel liquid enough to pump. Having to work on that piping was pretty awful and involved a fair amount of climbing/crawling and getting covered in tar and fiberglass. That part of the life I definitely do NOT miss...

 

[Steve Bailey]

I suspect that if and when the OP returns, we'll find out that this is actually a request for homework help.

 

[joseph_e2]

I suspect that if and when the OP returns, we'll find out that this is actually a request for homework help.

Very likely...

 

[Ken Moore]

Back in the day, the US Navy burned #6 fuel oil, also called bunker fuel. Same thing, had to heat it, to use it. Luckily for me, they changed over to #2 (aka diesel fuel marine) in the mid 70's.

In todays digital world, could you not build/control a gas pump with a variable stroke, pump? So many strokes to a gallon, the stroke would be adjusted based upon the material temperature.

 

[cardosocea]

+1

Back in another life on cargo ships, we burned Heavy Fuel Oil (HFO), aka residual fuel, aka disgusting tar that was whatever was left after the "good stuff" was cracked off.

I, like Ken, knew this as bunker fuel. It's one of the things that greatly annoys me when people bang on about cars and the environment whilst having 90% of their possessions manufactured in China or India and transported by ships burning this stuff.

I imagine your engines would be running at a nice rate to expel this out... I worked on a drillship idling 3 engines because DP3 is a must. Each time they rev'd them to "clear the exhaust" it was ridiculous the amount of soot spat out.

 

[Robb B]

I work with Bunker and Creosote daily! The tenacity of that stuff is incredible. It's like anti-seize, stains anything it touches, causes headaches, and smells bad, though I've gotten pretty used to it.

 

[joseph_e2]

It's weird how many names the same stuff has. We'd sometimes call it "bunker fuel" or "Bunker C" as well. Never figured out what the "proper" name is...
Thankfully, most of my offshore time was on workboats where we used #2 Diesel.