| 摘要 |
PURPOSE:To realize the constant amount control with high accuracy and excellent response proerty, by providing a control valve at the main and return sides, respectively and then giving the reverse action to both control valves to each other so as to ensure a certain liquid level for a relay tank. CONSTITUTION:When the pressure loss increases owing to the cake sticking to the filter cloth of a filter press 6, the flow rate is reduced to a main piping 5. At the same time, the discharge output of a pump 2 increases to increase the return flow rate to a branch pipe 10. As a result, the liquid level of a relay tank 1 increases. This increase is detected by a liquid level detector 8, and then the opening of a control valve 7B of the main side is reduced by a controller 9. Thus the liquid level is kept consant. As a result, the reduction of the liquid flow rate can be prevented for the press 6 in spite of the increase of the pressure loss. Furthermore, this control reduces the liquid feed resistance to the main side and at the same time, increases the resistance of the return side. Thus the quick and extremely excellent response property is ensured in terms of the control characteristics. |
