sewage is the main transmitter for differential pressure, pressure transmitter, float level gauge, and other instruments, as the media measurement with
dust, grease stain, the small , And other particles in the deposition of lead pipe pressure (or take the deposition of pressure valve), directly or indirectly affect the
measurement. Sewage cycle instrumentation work may be determined in accordance with their own practice.
sewage on a regular basis should pay attention to the following matters:
  sewage before staff and technology, access to technology staff can be recognized;
  flow pressure regulator or the sewage system before the first should be automatically switched to manual to ensure that the valve opening unchanged;
  for differential pressure transmitter, the sewage before the first of plus or minus three Manifolds take pressure valve related death;
  sewage container placed under the valve, slowly open the lead positive and negative pressure sewage pipe valve, so that the materials and Dirt into the container to prevent
Material directly into the trench, or a pollution to the environment, causing a waste of two years;
  valve because of poor quality, sewage valve switch will occur several times after Kwan's condolences to the dead, emergency measures are blind to increase
board to ensure that the sewage does not leak in a valve, so as not to affect measurement accuracy.
  open the valve block of plus or minus three pressure check valve, screw loose poor Pressure transmitter on the body of sewage (exhaust) for the sewage screw, row
completion of the sewage tightening screws;
  observation directing the instrument until the normal output, if the conditioning system, and automatically switch to manual.
  
2. Purge

Purge is blowing or the use of red fluid under test so that the media and Components measuring instruments or pipeline is not in direct contact so as to protect the measurement of
instrument and implement a method of measurement. Blowing through the pipeline to the measurement of quantitative measurement of objects in a row to blown gas.
red liquid is by measuring the pipeline to the quantitative measurement of objects in a row into the liquid.
for corrosive, viscous, crystal, melting, precipitation measured medium, the use of isolation and difficult way of
to meet the requirements when using Purge.
Purge typical way as shown in Figure 6-1-1.
Purge should pay attention to the following matters:
  Purge gas or liquid to be measured by the target process to allow the flow of media, usually it should meet the following requirements:
a. the measured and technique media do not react chemically;
b. clean, non-solid particles;
c. cut through the vacuum does not occur after the phase transition;
d. non-corrosive;
e. good mobility.
  Purge adequate and reliable source of supply of liquid from the impact of technology operations.
  Purge fluid pressure should be higher than that in the process of measuring points may be of the highest pressure to ensure that wind washing fluid
according to the design requirements for a steady flow of Purge.
  limiting the use or plate Transfer resistance of the rotor wind flowmeter measurement and control of washing liquid or gas flow.
  Purge fluids at the point of entry should be as close as possible to check the source of instrument parts (or close to the point of measurement), so that the wind flow to wash
in-line measurement of the pressure to keep down the minimum.
  as much as possible in order to reduce the measurement error, Purge request to be a constant flow of fluid. According to Purge the kind of fluid
category, as well as the characteristics of the measured media measurement requirements of the decision Purge flow, the following wind washing fluid value for reference:
a. Bed: Purge fluid for air or other gases, generally 0.85 ~ 3.4Nm3 / h.
b. trough of low pressure reservoir level measurement: Purge fluid for air or other gases, generally 0.03 ~ 0.045Nm3 / h.
c. general traffic measurement: Purge fluid for the gas, usually 0.03 ~ 0.14Nm3 / h; Purge fluid solution for
body, usually 0.014 ~ 0.036m3 / h.