Btukfyl

I am learning TikZ (which is a very elegant alternative to Inkscape and its workflow), however I am not very good at it at the moment.

I am trying to recreate this .svg which was done with Inkscape.

Here is the .tex ...

documentclass[12pt,border=5pt]{standalone}

usepackage{tikz}

usetikzlibrary{backgrounds}



begin{document}



begin{tikzpicture}[scale=1]

draw (0,0) rectangle (2,2.5) node[midway,align=center](Eluent) {};

draw (0,0) rectangle (2,2);%To simulate a filled cylinder.



draw (3,0) rectangle (7.5,2.5) node[above,midway,align=center](HPLC) {};



draw (12.5,0) rectangle (13.5,2.5) node[midway,align=center](Probe) {}; 

draw (12.5,0) rectangle (13.5,2);%To simulate a filled cylinder.



draw (8.5,3.5) rectangle (10,6) node[align=center,midway](Probeschleife) {};



draw  (16.5,0) rectangle (20.5,-2.5) node[pos=0.5](Detektor) {};



draw (10,8) rectangle (14,9) node[midway](Trenns){};





begin{scope}[on background layer]

draw [-to] (HPLC.north) |- (Probeschleife.west);

draw [-to](Probe.north) |- (Probeschleife.east);

draw [-to](Eluent) -- (HPLC);

draw [-to] (Probeschleife.north) |- (Trenns.west);

draw [-to] (Trenns.east) -- (18.5,8.5) -- (Detektor.north); %the middle coordinate is to move the path out of the main picture.

end{scope}



%labels

node [below] (Eluent) at (1,0) {Eluent}; 

node [below] (HPLC) at (5.25,0) {HPLC-Pumpe};

node [below] (Probe) at (13,0) {Probe};

node [below] (Detektor) at (18.5,-2.5) {Detektor};

node [left] (Probeschleifer) at (9.25,3.5) {Probeschleifer};

node [below] (Trenns) at (12,8) {Trennsäule};



end{tikzpicture}

end{document}

... which compiles to this PDF (I added the red arrows and boxes to show the issues):

I am trying to fix the following problems:

1. In the original diagram, the line connects "Eluent" and "HPLC-Pumpe" in the dashed way.




2. In the diagram, all of the lines which exit a part of the machine leave at the top / east side of the part. The red arrows show that this isn't the case.




3. I'd like to move the label of "Probeschleifer" away from the rectangle, to avoid overlaps.




4. I calculated the coordinates (18.5,8.5) by hand (by printing out the original Inkscape and measuring the distances). Is there a way to adjust the path from "Trennsäule" to "Detektor" easily, without it overlapping the diagram, i.e. going through the path "Probe -- Probeschleife[r]"? (Typo: should be ...schleife).




5. Is there a way to automatically have the labels offset? I.e. if I move one of the rectangles, I will also have to move the node.

Any additional feedback to the diagram is very helpful.

Thanks for your help!