Hitachi, Ltd.

Tsuyoshi Nishitarumizu

Masataka Koga

Tetsuya Matsui

Takehiko Kitamori

Masaharu Sakagami

Kenji Yokose

Kiwao Seki

Hiromi Yamashita

Konosuke Oishi

Toyoharu Okumoto

Taro Nogami

Takashi Iino

A plasma mass spectrometer generates an aerosol of a sample, by dissolving the sample in a liquid solvent, and spraying the liquid into a spray chamber via a nebulizer. The solvent condenses in the spray chamber and an aerosol of the sample then passes through a supply tube to a plasma torch. Microwave power from an output on the plasma torch converts the aerosol to a plasma, and the plasma passes to an analyzer. If microwave radiation reached the spray chamber, it would cause heating of the solvent which may evaporate it so that the solvent would be present in the plasma. Therefore, there is a wall between the spray chamber and the plasma torch and microwave output which blocks such microwave radiation.

Plasma mass spectrometer

The power density of a pulsed laser beam for irradiating a sample is adjusted to break down the sample into the form of a plasma. After the momentary breakdown of the sample into the form of a plasma, ions are generated having a high charge. Then, after a certain time elapses, the ions having a high charge recombine with the electrons in the plasma to provide monovalent or low valent ions. These low valent ions are taken out of the plasma and introduced to a mass spectrometric apparatus.

Method and apparatus for mass spectrometric analysis

A method of and an apparatus for analyzing a granular material contained in a sample of a medium such as water produced by an ultra-pure water producing apparatus includes the steps of adding energy to granular materials contained in a sample which is mixed with the medium, wherein the energy is set to be lower than the breakdown threshold of the medium and to be higher than the breakdown threshold of the granular materials, detecting ions which are generated with the breakdown of the granular materials by using a pair of positive and negative electrodes; and analyzing characteristics of the granular materials based on the ions.

Method of and apparatus for analyzing granular materials

A low pulsation displacement pump has a pair of plungers and motor driven-cams or feed screws for reciprocating the plungers. In order to cause the pump to stably discharge a liquid so that variation in discharge due to machining errors of the plungers or the feed screws is eliminated, the pump discharge pressure is measured at each of a plurality of predetermined operative positions of the plungers before delivery of the pump from a manufacturing plant, and machining errors are obtained in accordance with the thus-measured discharge pressure. Then, the speed correction factor for the motor is calculated for each of the plurality of predetermined positions of the plungers in accordance with the thus-obtained errors to store the results of the calculation in a memory. When the pump is used, the motor is operated while the speed of the motor is compensated for at each of the plurality of predetermined positions of the plungers in accordance with the speed correction factor stored in the memory, whereby the rate of discharge of pump can be kept substantially constant by preventing speed variation of the plungers due to machining error of the cams.

Low pulsation displacement pump

A low pulsation pump device has a pulse motor, two plungers adapted to be driven by the pulse motor, a pressure sensor disposed on the output side of the plungers, a storage for storing values of pressures detected by the pressure sensor during each of a number of periods, a high speed region during which the rotational speed of the pulse motor is increased. The pulse control has an optimization function which determines, on the basis of pressure information which was obtained during the last period, the location of a high speed region in each period in such a manner as to reduce pulsations.

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Katsuta, Japan

Tsuyoshi Nishitarumizu