Pressure information processing system suitable for use in a vacuum unit

• US 5,481,482 A
• Filed: 08/22/1994
• Issued: 01/02/1996
• Est. Priority Date: 09/05/1991
• Status: Expired due to Fees

• Current Assignee: SMC Kabushiki Kaisha
• Original Assignee: SMC Kabushiki Kaisha
• Inventors: Ito, Yoshiharu, Saito, Mitsuhiro, Matsushima, Hiroshi, Takebayashi, Takashi, Sugano, Shigeru, Nagai, Shigekazu
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): KEMPER, MELANIE A
• Application Number:
  US08/293,601
• Time in Patent Office: 498 Days
• Field of Search: 364/558, 364/550, 73/4 V, 73/4 R, 73/37, 73/749, 73/753, 294/64.1, 294/64.2, 137/557, 137/526, 15/319, 15/339
• US Class Current: 700/301
• CPC Class Codes: G05D 16/024 Controlling the inlet pressure, e.g. back-pressure regulator
• CPC Class Codes: G05D 16/2026 with a plurality of throttling means

Abstract

In a vacuum unit which can electrically process information, a vacuum pressure value is detected by a detecting device and a desired pressure value is set by a setting device. The so-set desired pressure value is digitally displayed on a displaying device and stored in a storing device. The set desired pressure value is compared with the detected vacuum pressure value by a determining device. When the result of comparison is brought to a given value, it is determined that an unusual or improper state has been developed. When the set desired pressure value and the detected vacuum pressure value coincide with each other in a predetermined range, a predetermined signal is produced from an output device. The displaying device is provided with an adjusting device capable of adjusting the state of visual recognition of each pressure value.

Claims

1. A system for processing pressure information for a vacuum unit operable on a workpiece, comprising:

(a) a vacuum generator for generating a vacuum;

(b) a vacuum generator detecting means for detecting a vacuum generator vacuum level of vacuum generated by said vacuum generator;

(c) an interface component which interfaces said vacuum generator with the workpiece;

(d) interface component detecting means for detecting an interface component vacuum level of vacuum in said interface component;

(e) determining means for determining whether a predetermined critical value has been met, wherein said interface component vacuum level is compared with said predetermined critical value, said predetermined critical value thereafter being adjusted as a function of said vacuum generator vacuum level to provide an adjusted predetermined critical value.

2. The system of claim 1, wherein said predetermined critical value is determined to be met if said interface component vacuum level has a local maximum value which is less than said adjusted predetermined critical value.

3. The system of claim 2, wherein said vacuum generator includes an ejector and said vacuum generator detecting means is proximate said ejector and comprises means for detecting a vacuum level.

4. The system of claim 1, further comprising control means for controlling an external device, wherein said adjusted predetermined critical value corresponds to a vacuum level in a predetermined pressure range defined by vacuum levels that have been detected by said vacuum generator detecting means, so that when said interface component vacuum level is within said predetermined pressure range, said control means is activated.

5. The system of claim 4, wherein said vacuum generator includes an ejector and said vacuum generator detecting means is proximate said ejector and comprises means for detecting a vacuum level.

6. The system of claim 1, further comprising means for determining a number of times said interface component vacuum level has a local maximum value that is less than said adjusted predetermined critical value;

and

wherein said predetermined critical value is determined by said determining means to be met if the number of times said interface component vacuum level has a local maximum value that is less than said adjusted predetermined critical value exceeds a predetermined number.

7. The system of claim 6, wherein said vacuum generator includes an ejector and said vacuum generator detecting means is proximate said ejector and comprises means for detecting a vacuum level.

8. A system of claim 1, further comprising display means for digitally displaying said vacuum generator vacuum level.