Motors: expansible chamber type – Plural relatively movable or rigidly interconnected working... – Condition responsive means for modifying working member...
Patent
1982-06-17
1985-04-16
Hershkovitz, Abraham
Motors: expansible chamber type
Plural relatively movable or rigidly interconnected working...
Condition responsive means for modifying working member...
91171, 91517, 92 49, F15B 1100
Patent
active
045108498
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to pneumatic and hydraulic control systems comprising a number of actautors, and more particularly to methods of synchronizing actuators and apparatus for implementing the same.
Still more particularly, the present invention relates to methods of and apparatus for synchronizing two or more actuators of prime or secondary movers operating in parallel into a common load.
The present invention can most advantageously be used in multiple-unit transport power plants comprising Diesel engines or turbines and providing at the same time the operation of an electric generator.
2. Description of the Prior Art
At present the ships of various types are often equiped with two-unit Diesel power plants where the movers operate into a common load, viz. one propeller. In those cases, when two or more prime or secondary movers operate into a common load it becomes necessary to provide equal load distribution between these units, especially when the load changes. Thus, for example, if the total load on the movers is sharply increased due to external reasons, each of these movers should continue to contribute into the total load, its contribution being equal in magnitude to that prior to the increase. It means that correlation between the contributions of individual movers to the total load should remain unchanged.
Equalization of the load is provided through corresponding synchronization of the operation of the mover actuators, in particular fuel or any other energy supply regulators. The main reasons accounting for unequal load distribution between the engines are the following:
unequal time of response to the change of the load in various movers or, in other words, unequal time constant of the movers;
unequal character of transmission, in actuators of different movers, of a control signal applied to said actuators from the common setting device into useful movement of their operating members due to unavoidable deviations in geometrical dimensions of the elements constituting the actuators as well as due to their temporary misadjustment, etc.;
unequal speed of transmission of control signals both through the common control circuit and through feedback circuits.
Unequal distribution of the load between the movers results in the loss of preset speed or moments and increased fuel consumption as well as underloading or overloading of some movers and thereby their premature ware and even failure. The present invention is directed at providing a method of synchronizing actuators and an apparatus implementing said method ensuring uniform distribution of the common load between the movers.
Known to the art is a method of synchronizing actuators (Cf. USSR Inventor's Certificate No. 496381, published in 1973), applied in control of mechanized tunnel shield. This method comprises the steps of measuring in the process of the tunnel shield operation, the values of displacement of the operating members, namely the rods of all hydrocylinders used therein with respect to a base point, deriving signals corresponding to the displacement of each rod, separating out of said signals the lowest one and separately comparing the obtained signals to derive a correction signal used for adjusting the position of the rod of each hydrocylinder through changing the supply of the pressure fluid to its operating volume, said correction signal being proportional in magnitude to the difference between the signal corresponding to the displacement of the rod of any hydrocylinder and the signal corresponding to the shortest displacement of all the rods relative to the base point.
Synchronization of hydrocylinders in accordance with this method is a complicated process requiring the sequence of the following procedures:
comparing the rod position of each hydrocylinder with the position of the base point;
selecting out of the displacement of the rods of hydrocylinders the shortest displacement;
deriving from several comparing devices control signals proportional in magnitude to
REFERENCES:
patent: 3048743 (1962-08-01), Chillson
patent: 3355993 (1967-12-01), Williamson
patent: 3772884 (1973-11-01), Witt
Khramtsov Alexandr A.
Shinder Ilya E.
Tsyrkin Mikhail I.
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