PRO AIR TPK 21 LT, Functional Description And Operating Instructions

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7.5 Adjustment of measurement chamber choke
10
Connection via a compressed-air hose:
This connection variant is ideal, for example, if the device is
intended for portable use or mounted onto a machine or
panel.
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Underneath, the 3/8" thread is fitted onto a 6/4 mm
hose.
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The choke is set to approximately 60 l/h for stationary
applications (factory setting, as delivered). If used as a
portable device for rapid measurements the setting should
be changed to approximately 240 l/h.
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NOTE: Use only PTFE hose for the connection.
The choke's factory default setting is a 60 l/h basic flow rate at a pressure of 10 bar. So long
as the choke has not been adjusted, no adjustment is usually required, provided that this is the
desired flow rate.
Depending on the type of connection, the choke can be closed to avoid the loss of scavenging
air. This is done by fully tightening the Allen screw using the socket spanner provided.
If used as a portable device for rapid measurements the basic flow rate should be set to
approximately 240 l/h. To do this, the choke is opened until the screw is in line with the top
edge of the measuring chamber. The venting noise can clearly be heard in this position. The
response is faster with a high basic flow rate.
To reset the choke to 60 l/h for stationary applications, a flow meter is required, which is fitted
over the screw using a flat seal. The desired flow rate is achieved by repeatedly adjusting and
checking the flow.
Precise adjustment of the desired flow rate is particularly important in the case of stationary
applications, because too high a flow rate results in high operating costs.