Fluids plumbing with capillary flowcell flushing

[christiankuttke]

The plumbing inside the box is connected to boat inlet and boat outlet.

During normal operation, fluid from boat inlet is pumped through the capillary flow cell and pumped to boat outlet.

To remove clogs from the capillary flow cell, the pump can be reversed.

The attached picture proposes a plumbing layout with check valves and a fluid repository which facilitates flushing using the available fluids.

[christiankuttke]

Check valves are very common parts with Luer Lock connector: https://www.mcmaster.com/2141N1/

Tee: https://www.mcmaster.com/51525K445/

The piston can be made using a syringe with Luer Lock outlet. The syringe can be placed in a 3D-printed holder preventing the plunger to be pushed past a certain point (or pushed out). e.g. 50ml https://www.mcmaster.com/7510A656/

To encourage filling of the piston, a needle valve (uncommon), controlled tube constriction (3D-printed) or stopcock on/off valve set to medium can be placed between the Tee to the piston and check valve close to boat outlet. https://www.mcmaster.com/7033T21/ This will increase the pressure at the piston inlet during normal operation, which may be necessary to fill the piston from line pressure alone. Worst-case, the piston will have to be primed with some fluid, then put in the 3d-printed assembly preventing excessive depletion as well as overfilling.

[christiankuttke]

The pump should be on the inlet side to the capillary to prevent cavitation of sample fluid in the capillary in the case that it is clogged.

In vivo this pump topology is common says Ibidi: https://ibidi.com/img/cms/products/instruments/I_1090X_PumpSystem/IN_1090X_pump_system.pdf#subsection.8.2

[beniroquai]

Ah, interesting, I was wondering why placing the pump after the flow cell would be better, but perhaps that'S the reason.

What would be the procedure to unclog the flow cell with the current system by means of valve, pump states?

Also, did you find a check valve suitable for us? We should proceed and prepare a shopping cart for mcmasters if these are the only ones that sell that stuff. Is there no other alternative a little more near by @ranranking ?

Edit: @christiankuttke would you add a filter when you create the bypass? Is there a T-connector with a filtering net in one arm?

[christiankuttke]

As I wrote in text previously, the pump should be placed at inlet of, in front of the flow cell.

I am sure there are other suppliers for this generic equipment. I will add a bill of materials some time in the next days and add recommended shop links if I find them.

I have decided against using filters because they will quickly clog or release the dirt when the flow is reversed.

[beniroquai]

Ok ;-)