2. After the period of preliminary air pressure, preservative is forced into the cylinder. As the preservative is
pumped in, the air escapes from the treating cylinder
into an equalizing or Rueping tank, at a rate that keeps
the pressure constant within the cylinder. When the
treating cylinder is filled with preservative, the treating
pressure is increased above that of the initial air and is
maintained until the wood will absorb no more preservative, or until enough has been absorbed to leave the
required retention of preservative in the wood after the
treatment.