Bottle filler-piston pump 3

[bamia]

Hello experts,

I would like to know the operation principles of the machine in this video.
It is a bottle filler machine with four pistons and an induction motor to move the four pistons at the same time.
In the picture you see a pneumatic actuator and I believe a ball valve; I could not find a brand for the actuator.
The valve is open to the nozzles except when the piston moving down as it shifts to draw product from the top tank.

So the piston moves up for timed period, stops, valve changes, piston comes down, valve opens.

The piston rods are attached to a tubing o the bottom; it has a collar inside the tubing to secure it from the top and is allowed to "float down all the way to the bottom of the tubing. On the bottom of the tubing there are four bolts that thread up to adjust how much the piston rod is allowed to float down.

The main question is why is the rod designed to float, how does that benefit the system?

Thank you.

 

[Compositepro]

The piston rods are not allowed to float. There is a central screw that moves the cross-bar up and down. The cross-bar moves the piston rods, which are rigidly attached. The piston rods have a reduced diameter threaded end with a nut.

 

[bamia]

Thanks Compositepro.

The assembly is designed for the rods to float or another term is they are allowed to move should they need to.

I will describe the assembly as much as I can, holes on top and bottom of the tubing for all four pistons, the piston rod is inserted in the top hole and let's say a washer and bolt are fastened to the bottom of the rod from inside the rectangular tubing. The tubing is approximately 4-5" high (did not measure it. Th bottom hole is threaded and each gets a bolt that just threads into the bottom only.
On the way up the bar/tubing moves up and any of the bolt on the bottom is not set to be already touching the rod then the bar will move up and the rod will slide in the hole until the bolt makes contact with the rod and then the rod is pushed up with the bar.
On the way down, the bar makes contact with the washers on the bottom of the rod to pull it down. So if the bar was not already making contact with the washer then it will move down a bit until it makes contact with the washer and pull the rod down.

If the rods are pulled all way up so the the washer are making contact with the bar/tubing and the bolts on the bottom are tightened all the way up and making contact with the rod; in that case the rod would be fastened rigidly as you described.

The question why make the assembly this way, it's a waste if without and objective.

 

[Artisi]

Have you tried asking the manufacturer, sounds to me like a good place to start?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[bamia]

Hi Artisi,

I thought it is common practice and wanted to learn but it now seems that is not the case.
Another question and again for the purpose of learning about piston pump operation in general, when the piston pulls a product in the seals should be tight that they do not allow any air and then push the product out and so on, ideally never allowing air in, is that accurate?

Thanks

 

[bimr]

The product volume in the bottle should be precise so there is no shortage or overage. The product volume is the same as the volume displaced by the piston, so yes, the seals have to be tight.

 

[Compositepro]

If the bolts were loose as you describe, there would be a "float". The video does not show any float and the bolts are tight, which is as it should be. Loose bolts would be a fault in the equipment, as they are in any machine. Your train of thought seems strange.

 

[bamia]

Thanks everyone.

@bimr, that makes sense and I needed someone to say that as I was starting to doubt myself.

@Compositepro, the machine is designed for the rods to move; the tubing is machined precisely to allow for the rods to move, brass bushings on top, flush plates on bottom with set screws, bolts with locking nuts to hold their position. The nuts were removed by the production personnel.

I have two options, say they're just incompetence and I know more than they do or try to find out what the engineering motive is behind their design.
I will contact them in a week or so for support with other equipment and will ask them about this one as well. For the time being I will leave it alone.

Thank you to everyone for your help.

 

[LittleInch]

bamia,

You're confusing yourself and us with all this talk of rods and bars and nuts and collars without know which bit of the assembly you're talking about.

Try sketching it out and naming or numbering the parts.

and add a blow up of the connection you're interested in.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bamia]

LittleInchm , very good point. Having no knowledge of pumping of any kind I thought it was common practice and that it would be self explanatory. I will get some pictures and supplement them with drawing in a few days.

Thanks