It is possible to convert a tank to the new valve but you will need to have the tank re certified before it can be refilled.
New vs old propane tank valve.
All propane gas cylinders under 40 lbs require an opd or an overfill protection device.
The next refinement of propane tank connections comes in the acme valve.
It is true that the new valves have both male and female threads.
Pol valves are the oldest standard for propane tank connections and newer types are more widely used.
When the level of liquid propane reaches the limit the float rises and the valve closes.
With out the overfill protection they will not or should not fill it.
A plug is screwed into the propane valve for transporting or storing the tank.
For the consumer there is little difference between an acme valve and an opd valve.
Tanks with the older acme valves are legal to use and transport but only those with opd valves can be legally filled.
This prevents more propane from being added to the tank.
It is not true that you can have an old style tank refilled.
Pol valves allow the release of gas without anything connected to it.
Any new cylinder should come with an opd valve installed.
Dozyant universal fit pol propane tank adapter with gauge converts pol lp tank service valve to qcc1 type 1 old to new connection type propane tank gauge 4 5 out of 5 stars 524 15 99 15.
This is an important safety measure.
Replacing a tank valve with an opd valve can be done at home.
Since april 2002 propane tanks without opd valves cannot be refilled.