The sample valve is usually mounted above the racking valve
on the tank and it screws into a coupling welded to the tank. You can also
order a 1-1/2” Triclamp® ferrule to be welded on instead. The sample valves come
in two styles, lockable and standard.
The standard valve has a threaded plunger which when
unscrewed releases wine through the port. It has two O-rings and is easy to
strip and clean and inspect the O-rings for damage. A little food grade Silicone on the
threads helps with ease of operation.
The lockable sample valve has a very similar operation. The
knurled knob has holes and matches a backing plate. You can put a padlock
through the knob and plate to secure the valve. This is often used on tanks
outside the winery building and on spirit tanks.