Hitachi, Ltd.

Tomoko Kikuchi

Katsumi Mabuchi

Michihiko Aizawa

Heihatiro Midorikawa

Takashi Honda

Masahiko Ito

Tsuneo Nakamura

Yasunobu Kani

Shinichi Yokosuka

An absorption refrigerator includes a high temperature regenerator for heating a water solution including a halogen compound to generate steam. An oxide film having thickness of 0.02&#x2013;5.0 &#x3bc;m, one of the colors blue, purple and gray, or a hydroxyl group is formed on a surface of at least one of the high temperature regenerators and the heat exchanger.

Absorption refrigerator and production method thereof

An absorption refrigerator includes a high temperature regenerator for heating a water solution including a halogen compound to generate steam. An oxide film having thickness of 0.02-5.0 &mgr;m, one of the colors blue, purple and gray, or a hydroxyl group is formed on a surface of at least one of the high temperature regenerators and the heat exchanger.

This invention relates to an improved apparatus and method for electrolytic descaling of steel strips. The apparatus comprises electrodes integrated with nozzles having jet openings for dispensing electrolyte onto the surface of the steel strips. By jetting the electrolyte to the steel strip in the air and applying a voltage to the electrode, the scale on the surface of the steel strip is removed. This jetting of electrolyte reduces the size requirement of the electrolyte tank storing the electrolyte because the required quantity of electrolyte decreases. The present invention does not require immersion of the electrodes in the electrolyte and thus avoids the problem of short-circuiting that occurs with submerged electrodes. This results in a significant improvement in electric power efficiency. By individually adjusting the jet pressure of the electrolyte jets, the waving and the flexure of the steel strip is prevented and the electrodes can be arranged close to the steel strip to reduce required electric power. With the reduction in short circuit currents, many electrodes can be provided and the speed of the descaling can be increased as a result of the increase in electric current to the steel strip.

Steel strip descaling apparatus and a steel strip manufacturing apparatus using the descaling apparatus

A pickling plant for a steel strip and a method for controlling the pickling plant, including monitoring at least one quantity of state represented by thickness, width and quantity of scale of the steel strip, and at least one quantity of state of operation of a plant represented by concentration, quantity and temperature of acid supplied into a pickling tank of the pickling plant, line speed of the steel strip, and temperature of the steel strip immediately before entering the pickling tank calculating on the basis of values of said quantity of state and quantity of state of operation, at least one of concentration distribution of acid, concentration distribution of iron and descaling rate at optional plural positions, and on the basis of the calculating the optimum quantity of state for operation of the plant is determined.

Pickling plant and method of controlling the same

An absorption refrigerator uses water as a refrigerant and a halogen compound as an absorption solution, and is characterized in that an oxide film of thickness of 0.02-5.0 .mu.m is formed on a surface of at least one of a heat exchanger and a high temperature regenerator. And a production method of the absorption refrigerator is characterized by oxidizing a surface of at least one of a heat exchanger and a high temperature regenerator at a temperature of 200-800.degree. C., and adjusting a heating temperature and a heating retaining time so that a value of parameter (P), obtained according to P=T (5+log t) is 3.5-6.0.times.10.sup.3, wherein T represents heating temperature (.degree.K), and t heating retaining time (minute).

An absorption refrigerator uses water as a refrigerant and a halogen compound as an absorption solution, and is characterized in that an oxide film of thickness of 0.02-5.0 .mu.m is formed on a surface of at least one of a heat exchanger and a high temperature regenerator. And a production method of the absorption refrigerator is characterized by oxidizing a surface of at least one of a heat exchanger and a high temperature regenerator at a temperature of 200.degree.-800.degree. C., and adjusting a heating temperature and a heating retaining time so that a value of parameter(P), obtained according to P=T (5+log t) is 3.5-6.0.times.10.sup.3, wherein T represents heating temperature (.degree.K), and t heating retaining time (minute).

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Ibaraki, Japan

Tomoko Kikuchi