| 摘要 |
PURPOSE:To discriminate the danger of the degree of galling in an injection plunger mechanism by measuring the liquid pressure in an operating cylinder which operates an injection plunger and the differentiated value of the liquid pressure. CONSTITUTION:The liquid pressure in an operating cylinder 15 of an injection plunger is detected with a pickup element 21 of a pressure detector, is amplified by an amplifier 22 and is fed to the 1st comparator 25. Said pressure value is also fed, via a differentiation circuit 23 to the 2nd comparator 26. The 1st comparator 25 outputs the 1st output signal when the liquid pressure in the cylinder 15 is at a prescribed value or above and the 2nd comparator 26 outputs the 2nd output signal when the change in the liquid pressure in the cylinder 15 is sharp, that is, when the operation of the cylinder is stuck. The injection distance until the galling of the plunger arises is detected in the 1st latching counter 36 and the injection distance until the galling ends is detected in the 2nd latching counter 37. An arithmetic circuit 41 calculates the extent of movement only from the galling state of the plunger tip from both signals from the counters 36, 37 and transmits the same to the 3rd comparator 45. The comparator 45 actuates an alarm system 48 when said signal attains the value set by a setter 46 or above. |
