An explanation of proposed usage:
Many year ago my job was assisting anaesthetists in hospital operating theatres. One diagnostic technique we used was to insert a central venous pressure catheter for monitoring blood volume. The CVP line was a long thin plastic tube that was inserted over a thin wire and into a vein. Once the distal end of the wire was in the right anatomical place, the catheter was slid over the top. Once the tip of the catheter was in the right spot, the guide wire could be removed.
Fast forward 40 years and I’m now running a repair shop specialising in coffee machines.
Coffee machine water heaters generally comprise of a spiral of metal tubing cast into a metal block together with the heating element. These heaters often block up with limescale right in the middle of the length of pipe. Injecting an acid solution at the inlet/outlet port fails because the liquid hits an air block in front of the limescale. My technique is to insert a fine PTFE pipe into the inlet/outlet until it hits the limescale – I then inject the acid. To help get the pipe into the right place I’d like to add some rigidity to the PTFE pipe by having some thin (0.3mm) spring steel inside the pipe to help guide its way….
Alternatively, put the wire in first, then slide the pipe over the top – then remove the wire.
Thanks again.
https://en.wikipedia.org/wiki/Seldinger_technique
www.youtube.com/watch?v=HuJzn_PF118
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