Patents Assigned to Instrumentarium Corporation
  • Patent number: 5038790
    Abstract: The invention relates to a method and an apparatus for controlling the cuff pressure in a sphygmomanometer. The pressure control mechanism for a cuff (3) consists of one or a plurality of valves (4) whose operation is controlled by a control element (5) in a manner that the pulse frequency of valve (4) or valves (4) exceeds that of the heart. By using a pulse-controlled high-speed so-called on-off valve it is possible to effect the cuff pressure drop in a completely linear fashion by opening and closing the valve at a necessary frequency and by adjusting the durations of the on- and off-periods of said valve or valves.
    Type: Grant
    Filed: May 25, 1989
    Date of Patent: August 13, 1991
    Assignee: Instrumentarium Corporation
    Inventor: Lauri J. Malkamaki
  • Patent number: 5023555
    Abstract: The invention provides a magnetic resonance imaging apparatus having a primary field generating means for generating a substantially uniform magnetic field, wherein that said primary field generating means is arranged in use to generate a magnetic field the field direction of which varies with time, e.g. a rotating field. The varying field operates to average out from the magnetic field experienced by the sample being imaged at least some of the external perturbing magnetic fields so reducing the sensitivity of the apparatus to such external fields.
    Type: Grant
    Filed: January 2, 1990
    Date of Patent: June 11, 1991
    Assignee: Instrumentarium Corporation
    Inventor: Gosta J. Ehnholm
  • Patent number: 5003981
    Abstract: The invention relates to an identification method for the cuff of a non-invasive automatic sphygmomanometer and to a flow restriction means for moderating the rate of pressure increase or decrease or both. Such a flow restriction means, which is fitted e.g. in a separate adapter (4), is useful particularly in connection with small-sized cuffs (6) intended for newborn babies. On the other hand, when using larger, such as adult cuffs, it is preferably to omit a flow restriction means completely. Identification is based on the fact that, when using a flow restriction means, either the increase of pressure downstream of a flow restriction means or the decrease of pressure upstream of a flow restriction means occurs slowly after the pumping is finished. If there is no flow restriction means at all, there will be no pressure change after the pumping is finished. Through the intermediary of a pressure sensing element (9), a control element (10) detects the size of a cuff.
    Type: Grant
    Filed: July 6, 1989
    Date of Patent: April 2, 1991
    Assignee: Instrumentarium Corporation
    Inventors: Lauri P. A. Kankkunen, Raimo A. T. Piskunen, Borje T. Rantala