Patents by Inventor Naser Mahmud Chowdhury

Naser Mahmud Chowdhury 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).

  • Patent number: 6742282
    Abstract: A method and an apparatus are disclosed for detecting an occurrence of a liquid dry condition in a container containing a liquefied compressed gas while the gaseous phase of the liquefied compressed gas is being removed from the container over time. The apparatus includes a first sensor, a second sensor, and a computer, preferably a programmed logic controller (PLC). The first sensor senses temperature (T) inside the container and provides a signal indicative thereof. The second sensor senses pressure (P) inside the container and provides a signal indicative thereof. The computer receives signals from the first and second sensors, and determines the rates of change in the pressure (dP/dt) and the temperature (dT/dt) inside the container over time.
    Type: Grant
    Filed: November 20, 2002
    Date of Patent: June 1, 2004
    Assignee: Air-Products and Chemicals, Inc.
    Inventors: Naser Mahmud Chowdhury, Sukla Chandra, Warren Matthew Janigian
  • Patent number: 6643951
    Abstract: A method and an apparatus are disclosed for detecting an occurrence of a liquid dry condition in a container containing a liquefied compressed gas while the gaseous phase of the liquefied compressed gas is being removed from the container over time. The apparatus includes a first sensor, a second sensor, and a computer, preferably a programmed logic controller (PLC). The first sensor senses temperature (T) inside the container and provides a signal indicative thereof. The second sensor senses pressure (P) inside the container and provides a signal indicative thereof. The computer receives signals from the first and second sensors, and determines the rates of change in the pressure (dP/dt) and the temperature (dT/dt) inside the container over time.
    Type: Grant
    Filed: October 23, 2000
    Date of Patent: November 11, 2003
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Naser Mahmud Chowdhury, Sukla Chandra, Warren Matthew Janigian
  • Publication number: 20030084589
    Abstract: A method and an apparatus are disclosed for detecting an occurrence of a liquid dry condition in a container containing a liquefied compressed gas while the gaseous phase of the liquefied compressed gas is being removed from the container over time. The apparatus includes a first sensor, a second sensor, and a computer, preferably a programmed logic controller (PLC). The first sensor senses temperature (T) inside the container and provides a signal indicative thereof. The second sensor senses pressure (P) inside the container and provides a signal indicative thereof. The computer receives signals from the first and second sensors, and determines the rates of change in the pressure (dP/dt) and the temperature (dT/dt) inside the container over time.
    Type: Application
    Filed: November 20, 2002
    Publication date: May 8, 2003
    Inventors: Naser Mahmud Chowdhury, Sukla Chandra, Warren Matthew Janigian
  • Publication number: 20020174893
    Abstract: An apparatus is disclosed for detecting an occurrence of a liquid dry condition in a container containing a liquefied compressed gas while the gaseous phase of the liquefied compressed gas is being removed from the container over time. The apparatus includes a first sensor, a second sensor, and a computer, preferably a programmed logic controller (PLC). The first sensor senses temperature (T) inside the container and provides a signal indicative thereof. The second sensor senses pressure (P) inside the container and provides a signal indicative thereof. The computer receives signals from the first and second sensors, and determines the rates of change in the pressure (dP/dt) and the temperature (dT/dt) inside the container over time.
    Type: Application
    Filed: March 23, 2001
    Publication date: November 28, 2002
    Inventors: Naser Mahmud Chowdhury, Sukla Chandra, Warren Matthew Janigian
  • Patent number: 6134805
    Abstract: A method [and an apparatus are] is disclosed for detecting an occurrence of a liquid dry condition in a container containing a liquefied compressed gas while the gaseous phase of the liquefied compressed gas is being removed from the container over time. The [apparatus includes] method uses a first sensor, a second sensor, and a computer, preferably a programmed logic controller (PLC). The first sensor senses temperature (T) inside the container and provides a signal indicative thereof. The second sensor senses pressure (P) inside the container and provides a signal indicative thereof. The computer receives signals from the first and second sensors, and determines the rates of change in the pressure (dP/dt) and the temperature (dT/dt) inside the container over time.
    Type: Grant
    Filed: August 24, 1998
    Date of Patent: October 24, 2000
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Naser Mahmud Chowdhury, Sukla Chandra, Warren Matthew Janigian
  • Patent number: 6085548
    Abstract: A control vent system is disclosed for reducing volatile impurities in a gaseous product of ultra-high purity delivered from a storage vessel containing an inventory of a non-cryogenic liquid product, as well as a method and a system for delivering the product from the storage vessel. The control vent system includes a vent line attached to the storage vessel and a condenser in the vent line. Coolant (e.g., a refrigerant) is transferred between the condenser and a source of coolant, such as a refrigeration unit. The method of reducing volatile impurities includes three steps. The first step is to vent part of the gaseous vapor from the gaseous vapor space to a condenser. The second step is to cool the vented gaseous vapor in the condenser to a temperature below the boiling point of the liquid product and above the boiling points of the volatile impurities. As a result, a first portion of the vented gaseous vapor is condensed and a second portion of the vented gaseous vapor is not condensed.
    Type: Grant
    Filed: August 24, 1998
    Date of Patent: July 11, 2000
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Naser Mahmud Chowdhury, John Irven, Dao-Hong Zheng, Sukla Chandra, Kenneth Coull, Reiner Reinhard Wilhelm Taege
  • Patent number: 5685350
    Abstract: Method and apparatus for transporting, storing and delivering dangerous chemicals in a high pressure stacked tube array configuration. Tubes are divided into sub-groups with outside tubes containing inert gases and inside tubes containing chemicals. Inside and outside tubes in each sub-group are manifolded to permit off loading of dangerous chemicals into outside tubes in the event of a leak in an inside tube or tubes in the sub-group. The apparatus includes a manifold system for segregation of source chemicals to provide two independent outlets.
    Type: Grant
    Filed: February 7, 1996
    Date of Patent: November 11, 1997
    Assignee: Air Products and Chemicals, Inc.
    Inventor: Naser Mahmud Chowdhury
  • Patent number: 5644921
    Abstract: A method and apparatus for storing ultra high purity non-cryogenic liquefied compressed gases, such as ammonia (NH.sub.3), and delivering a vaporized gaseous product from those liquefied gases for semiconductor processing applications. The delivery method includes withdrawing and heating gaseous product from a storage vessel containing the liquefied compressed gas, and then piping the heated gas through the liquid contained in the storage vessel in a heat exchange fashion. The heat exchange with the liquid inside the vessel induces boiling to maintain a vaporized gaseous product under a minimum positive pressure in said vessel. After liberating its heat, the gaseous product is delivered to a semiconductor manufacturing point of use.
    Type: Grant
    Filed: May 22, 1996
    Date of Patent: July 8, 1997
    Assignee: Air Products and Chemicals, Inc.
    Inventor: Naser Mahmud Chowdhury