Fluent material handling – with receiver or receiver coacting mea – With signal – indicator – recorder – inspection means or exhibitor
Reexamination Certificate
2002-07-10
2004-05-04
Huson, Gregory L. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
With signal, indicator, recorder, inspection means or exhibitor
C141S286000, C141S144000, C141S192000
Reexamination Certificate
active
06729366
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a liquid filling apparatus and more particularly to an improvement in an apparatus that fills containers with liquid and is provided with liquid flow meters.
2. Prior Art
Liquid filling apparatuses that fill containers with liquid have been known, and one type thereof is a flow meter type liquid filling apparatus.
A typical flow type liquid filling apparatus includes a plurality of filling nozzles that have feed-out openings and opening-and-closing valves, valve actuating means which are installed at positions that correspond to the respective filling nozzles and which open and close the valves of the respective filling nozzles, a reservoir tank which stores a liquid, a liquid supplying means which is connected to the upstream side of the reservoir tank, an air pressure adjustment means which adjusts the air pressure inside the reservoir tank, liquid pipe channels which branch from the reservoir tank via a distribution chamber and is connected to the respective filling nozzles, and flow meters which are disposed in the branched liquid pipe channel so as to correspond to the respective filling nozzles.
Japanese Patent Application Laid-Open (Kokai) No. 11-193094 discloses a rotary type liquid filling apparatus.
This filling apparatus includes filling mechanisms which are disposed at fixed intervals in the circumferential direction on a rotating body that rotates continuously and fill containers with a liquid. The apparatus further includes a reservoir tank which stores the liquid, a liquid supplying means connected to the reservoir tank, a pressurizing means which pressurizes the interior of the reservoir tank, and liquid pipe channels which branch from the reservoir tank via a distribution chamber and are connected to the respective filling nozzles.
In this liquid filling apparatus, the pressure-adjustment valve of the pressurizing means is controlled on the basis of detection signals of a liquid pressure sensor that is installed adjacent to the reservoir tank so that air at a constant pressure is introduced into the reservoir tank. When it is detected by a liquid surface sensor that the liquid surface level inside the reservoir tank has dropped below a specified height, the liquid supplying means is actuated on the basis of the detection signal of this liquid surface level sensor so as to replenish the liquid inside the reservoir tank, thus maintaining the liquid pressure inside the reservoir tank and liquid pipe channels at a constant value.
Such liquid filling apparatuses include an apparatus in which flow meters corresponding to the respective filling nozzles are disposed in the branched liquid pipe channel. In this filling apparatus, the filling valves are opened as a result of the actuation of a valve actuating means at a specified timing by a control device at the time of filling, and the filling valves are closed as a result of the actuation of the valve actuating means by the control device at a point in time where the flow rate detected by the flow meters has reached a specified value, so that the amount of liquid with which the containers (e.g., bags) are filled is maintained at a constant value.
In cases where the liquid is flowing through the pipe channels at a certain flow velocity or greater, i.e., in cases where the valves are in a fully open state, the flow rate in the liquid pipe channels measured by such flow meters can be accurately measured even if the liquid pressure is not constant. However, when the valves open or close, it is difficult to achieve an accurate measurement of the flow rate (injection amount) of the liquid flowing through the pipe channels, since the flow velocity is small and varies abruptly. Furthermore, this flow rate fluctuates greatly with the liquid pressure. Accordingly, in a flow meter type liquid filling apparatus, it is necessary to maintain the liquid pressure in the vicinity of the filling nozzles at a constant value in order to maintain the amount of liquid with which the containers are filled (including the injection amount) at a constant value.
However, conventional flow meter type liquid filling apparatuses have problems as follows:
(1) Since the precision of the control of the air pressure in the reservoir tank by the pressurizing means is not very good (i.e., the air pressure inside the reservoir tank shows large fluctuations), it is difficult to maintain the liquid pressure at a constant value. Especially in the case of liquids that have a low viscosity, the liquid pressure used for filling must be set at a low value, so that the air pressure inside the reservoir tank must also be controlled to a low value. In such cases, however, control with good precision is achieved in a conventional apparatus.
(2) Even if the liquid pressure in the reservoir tank or in the liquid pipe channel adjacent to the reservoir tank is maintained at a constant value, the liquid pressure in the vicinity of the filling nozzles may not be constant. More specifically, the pressure loss caused by the resistance of the piping extending from the installation position of the liquid pressure sensor (i.e., the liquid pressure measurement position) to the filling nozzles increases with an increase in the viscosity of the liquid; and if the temperature of the liquid varies or the air temperature varies (e.g., between morning and noontime) so that the viscosity of the liquid varies, then the liquid pressure in the vicinity of the filling nozzles will fluctuate even in cases where the liquid pressure sensor shows the same liquid pressure.
(3) There are also problems in the detection precision itself of the liquid pressure detected by the liquid pressure sensor. In other words, in cases where the valves of a plurality of filling nozzles are successively opened and closed, an abnormal pressure is outputted as a result of the phenomenon of water hammer when the valves are closed. Furthermore, air contained in the liquid may remain in the position of the liquid pressure sensor, so that sharp accurate detection becomes impossible because of the compressibility of air.
SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to eliminate such problems in a conventional flow meter type liquid filling apparatus, so that the liquid pressure in the vicinity of the filling nozzles is maintained at a constant value, and the amount of liquid with which the containers are filled is maintained at a constant value.
The above object is accomplished by a unique structure for a flow meter type liquid filling apparatus that comprises:
a plurality of filling nozzles each having a feed-out opening and a valve that opens and closes,
a valve actuating means installed at a position that corresponds to each filling nozzle and opens and closes the valve of each filling nozzle,
a reservoir tank which stores a liquid therein,
a liquid supplying means connected to an upstream side of the reservoir tank,
an air pressure adjustment means which adjusts air pressure inside the reservoir tank,
a liquid pipe extending from the reservoir tank to a distribution chamber and then branched into liquid pipe channels each connected to each one of the filling nozzles,
a liquid pressure sensor which detects a pressure of a liquid inside the liquid pipe, and
a flow meter disposed on each one of the liquid pipe channels at a position that corresponds to each filling nozzle; wherein
the air pressure adjustment means is actuated on the basis of a detection signal of the liquid pressure sensor, thus adjusting the air pressure inside the reservoir tank so that the pressure of the liquid inside the liquid pipe is maintained at a constant value, and
the valve of each one of the filling nozzles is opened by the valve actuating means at a specified timing and is closed by the valve actuating means on the basis of the measurement signal of each one of the flow meters, thus filling containers with a fixed amount of a filling liquid; and wherein
the air pressure adjustment means is comprised of:
a pressurized air su
Koga Shoichi
Okazaki Hiroyuki
Tanaka Namiyoshi
Huson Gregory L.
Huynh Khoa D.
Koda & Androlia
Toyo Jidoki Co., Ltd.
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