Apparatus for metering and discharging a liquid

• US 5,277,333 A
• Filed: 02/28/1992
• Issued: 01/11/1994
• Est. Priority Date: 07/10/1990
• Status: Expired due to Term

• Current Assignee: General Electric Company, Musashi Engineering, Inc
• Original Assignee: Musashi Engineering, Inc
• Inventors: Shimano, Ichiro
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): Bomberg, Kenneth
• Application Number:
  US07/836,011
• Time in Patent Office: 683 Days
• Field of Search: 222/14, 222/55, 222/57, 222/61, 222/639, 222/644
• US Class Current: 222/14
• CPC Class Codes: B05B 12/02 for controlling time, or sequence, of delivery
• CPC Class Codes: B05C 11/1002 Means for controlling supply, i.e. flow or pressure, of liquid or other fluent material to the applying apparatus, e.g. valves
• CPC Class Codes: B05C 17/00573 the reservoir or container being pneumatically or hydraulically pressurized B05C17/0054, B05C17/015 take precedence
• CPC Class Codes: B05C 5/02 the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
• CPC Class Codes: B29B 7/726 Measuring properties of mixture, e.g. temperature or density B29B7/724 takes precedence
• CPC Class Codes: B29B 7/728 Measuring data of the driving system, e.g. torque, speed, power, vibration B29B7/724 takes precedence
• CPC Class Codes: B29B 7/7409 with supply of gas
• CPC Class Codes: G05D 7/0658 the plurality of throttling means being arranged for the control of a single flow from a plurality of converging flows G05D7/0652 takes precedence; ratio control G05D11/13

Abstract

An apparatus for accurately dispensing a predetermined amount of viscous liquid such as conductive adhesive, cream solder and the like. The apparatus includes a first pressure sensor arranged in a pipe line connected between a dispensing solenoid valve and a syringe, and a second pressure sensor and an accumulator arranged in a pipe line connected between the dispensing solenoid value and an air supply so that an output is controlled in accordance with variation of an integral valve of pressure measured by the first pressure sensor integrated with a preset output time of the shifting output signal thereby controlling the dispensing of liquid based on the remaining amount of liquid in the syringe and the variation in the internal pressure in the syringe to accurately discharge the predetermined amount of liquid and prevent dripping of liquid from the syringe.

Claims

1. A liquid dispensing apparatus comprising:

a syringe containing liquid;

an air supply coupled to the syringe for supplying air under a positive pressure to the syringe;

a dispensing solenoid valve disposed between the syringe and the air supply;

a first pipe line disposed between the syringe and the dispensing solenoid valve;

a second pipe line disposed between the dispensing solenoid valve and the air supply;

a first pressure sensor for measuring the internal pressure in the first pipe line;

a second pressure sensor for measuring the internal pressure in the second pipe line;

an accumulator coupled to the second pipe line;

a controller means for outputting a shifting output signal to the dispensing solenoid valve and for controlling an output time of the shifting output signal in accordance with a variation of an integral value of pressure measured by the first pressure sensor integrated during a preset output time of the shifting output signal after communicating with the first and second pipe lines;

a suction solenoid valve coupled to the dispensing solenoid valve by a third pipe line;

an air suction source coupled to the suction solenoid valve by a fourth pipe line;

a vent solenoid valve coupled to the third pipe line; and

an accumulator coupled to the fourth pipe line, each of the solenoid valves being coupled to the controller.