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Safety rules for use
(2）Adjust and set the amount of pressure by referring to the following "Table 1.
Open limit of the blow-off pressure relief needle".
(3）Reconfirm if the vacuum characteristics and the evacuation time are not influenced
and abnormal after setting the blow-off pressure.
(4）Adjust the desired blow-off air rate by blow-off air rate adjustment needle.
(5）Others
Table 1. Open limit of the blow-off pressure adjustment needle
1）When the pressure adjustment needle opening is adequate, a vacuum rising becomes like
① in the below graph.
2）If the pressure adjustment needle opening exceeds the limit, a vacuum rising becomes like
② in the below graph and evacuation time becomes longer.
3）If the pressure adjustment needle is opened more from
② of below graph, a vacuum rising becomes like
③ in the below graph and proper vacuum level cannot be obtained.
Vacuum characteristics
H：High-vacuum type
L：Large-flow type
E：High-vacuum at low air supply pressure type
Nozzle bore（mm）
Max. open limit (rotations)
In case of External Vacuum Controller“VJP Series”(VJP□), open limit of of the blow-off pressure needle differs according to the
performance of a vacuum pump. Adjust the needle within the condition under which the startup time and vacuum level are not affected.
Table 1 represents the referential values at rated supply pressure. Open limit of the blow-off pressure needle can change by factors
such as supply pressure, vacuum characteristics and volume of piping at vacuum side. Values in table 1 are only reference valves.
※Be noted that the evacuation time may become longer or normal final vacuum level may not be obtained when the pressure
adjustment needle opening exceeds the limit indicated in Table 1. (Please refer to the following (5) Others.)
※Increase the amount of blow-off air if shorter blow-off air time is required.
※Decrease the amount of blow-off air flow in order to avoid a work from being blown away.
Signal of Suction
solenoid valve
Final vacuum
Evacuation time delay caused by
longer response time due to
closed relief valve.
Normal vacuum level is not achieved
since the relief valve is not closed.
Atmospheric pressure
Vacuum pr
essur
e
→ Time