Patents by Inventor Isao Yamada

Isao Yamada has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Process for simultaneously drying mechanical wood pulp and improving mechanical strength and brightness of the pulp
    Patent number: 4183146
    Abstract: Disclosed is a process for simultaneously drying mechanical wood pulp and improving the mechanical strength and brightness of the wood pulp by mixing mechanical wood pulp with an aqueous solution of at least one sulfonating compound, the resultant mixture having a dry solid consistency of 20 to 50% of the wood pulp, based on the weight of said mixture and; bringing the mixture into contact with a heating gas having a temperature higher than 100.degree. C. to cause the dry solid consistency of the wood pulp in the mixture to be increased to a range of from 65 to 90% by weight.
    Type: Grant
    Filed: March 3, 1978
    Date of Patent: January 15, 1980
    Assignee: Oji Paper Co., Ltd.
    Inventors: Haruo Tsukamoto, Kazuo Koide, Yuzo Okazaki, Isao Yamada
  • Control system for D.C. motor
    Patent number: 4064443
    Abstract: In the control system, the motor is supplied power in the form of a pulse train. The width of each pulse of the pulse train is modulated through the comparison between a reference voltage and the counter e.m.f. of the motor immediately prior to feeding of each pulse of the pulse train into the motor.
    Type: Grant
    Filed: December 2, 1975
    Date of Patent: December 20, 1977
    Assignee: Ricoh Co., Ltd.
    Inventors: Isao Yamada, Isamu Shibata