Cleaning & Inspection Procedures for Differential Pressure Recorders

The DP Cell unit on Palmer Differential Pressure Recorders is made of Steel and has a safe working pressure of 2,500 psi.  The housing is secured with a quantity of 6 steel bolts of size 1/2-13 x 5.5.

When using these instruments in applications where solids or semi-solids may accumulate inside the pressure housings, periodic inspection and cleaning is required, as follows:

  1. Discontinue the use of the differential pressure unit, removing all pressure connections. from the recorder.
  2. Remove the pressure housing from the bellows unit assembly with care.  If the accumulation of material inside the housing is extensive, rapid removal of the housing may damage the bellows indentations.
  3. Remove the accumulation from between the bellows indentations and from inside the housing, using a solvent if possible.  Do not use a sharp instrument to clean between the indentations.
  4. Take care that there are no broken range springs in the DP unit.
  5. Replace the housings and O rings.
  6. Reattach the DP cell pressure housing.
    1. Lubricate the first two threads of the housing bolts with a graphite based grease, a Teflon based pipe dope, or a Molykote G paste.
    2. The torque on the bolts should be accomplished in 3 or 4 steps, setting the pressure housing bolts to the appropriate torque values using a torque wrench.
    3. Tighten all the bolts uniformly to 95 foot pounds (95 ft. lb.) of torque.