Abstract: Provided is a reactor device in which a fixed bed multi-tubular reactor is used to produce alkenyl acetate through a gas phase catalytic oxidation reaction of a lower olefin, acetic acid, and oxygen, and which enables accurate measurement of the temperature of a catalyst layer in a reaction tube even when a process operation has been carried out for a long time. A fixed bed multi-tubular reactor for producing alkenyl acetate, wherein the fixed bed multi-tubular reactor is equipped with a plurality of reaction tubes to which a raw material gas and a mist of an aqueous solution of an alkali metal acetate are supplied from the upper portion of the fixed bed multi-tubular reactor, a thermometer protection tube inserted into at least one of the plurality of reaction tubes from the lower portion of the fixed bed multi-tubular reactor, and a thermometer inserted into the thermometer protection tube.

Abstract: It is an object of the present invention to provide an effective technique for achieving a higher level of water quality control in a water treatment apparatus. Representative water treatment apparatus according to the present invention may include a purifying section, a sterilizing section, a water storing section and a water quality detection sensor. The water quality detection sensor is immersed in the water storing section. The water quality detection sensor not only serves as a means for detecting the quality of water in the water storing section, but also as a means for detecting deposition of biomembrane on the detecting section of the water quality detection sensor due to deterioration of the sterilizing performance of the water storing section. As a result, an efficient water quality control system can be realized.

Abstract: It is an object of the invention to provide an effective technique for detecting the quality of water with high accuracy. A representative water treatment apparatus includes an aerobic treatment region that treats water aerobically, a downstream region in which the water aerobically treated in the aerobic treatment region flows, a water quality sensor that is submerged in the downstream region and detects the water quality and a sensor washing arrangement that washes the water quality sensor by supplying the water of the downstream region to the water quality sensor at a flow rate higher than water flowing around the water quality sensor. As a result, sludge generated due to aerobic treatment can be prevented from being deposited on the water quality sensor and/or deposited sludge can be removed, so that the accuracy of water quality detection of the water quality sensor can be enhanced.

Abstract: It is an object of the invention to provide an effective technique for detecting the quality of water with high accuracy. A representative water treatment apparatus includes an aerobic treatment region that treats water aerobically, a downstream region in which the water aerobically treated in the aerobic treatment region flows, a water quality sensor that is submerged in the downstream region and detects the water quality and a sensor washing arrangement that washes the water quality sensor by supplying the water of the downstream region to the water quality sensor at a flow rate higher than water flowing around the water quality sensor. As a result, sludge generated due to aerobic treatment can be prevented from being deposited on the water quality sensor and/or deposited sludge can be removed, so that the accuracy of water quality detection of the water quality sensor can be enhanced.

Abstract: It is an object of the invention to provide an effective technique for detecting the quality of water with high accuracy. A representative water treatment apparatus includes an aerobic treatment region that treats water aerobically, a downstream region in which the water aerobically treated in the aerobic treatment region flows, a water quality sensor that is submerged in the downstream region and detects the water quality and a sensor washing arrangement that washes the water quality sensor by supplying the water of the downstream region to the water quality sensor at a flow rate higher than water flowing around the water quality sensor. As a result, sludge generated due to aerobic treatment can be prevented from being deposited on the water quality sensor and/or deposited sludge can be removed, so that the accuracy of water quality detection of the water quality sensor can be enhanced.

Abstract: It is an object of the invention to provide an effective technique for detecting the quality of water with high accuracy. A representative water treatment apparatus includes an aerobic treatment region that treats water aerobically, a downstream region in which the water aerobically treated in the aerobic treatment region flows, a water quality sensor that is submerged in the downstream region and detects the water quality and a sensor washing arrangement that washes the water quality sensor by supplying the water of the downstream region to the water quality sensor at a flow rate higher than water flowing around the water quality sensor. As a result, sludge generated due to aerobic treatment can be prevented from being deposited on the water quality sensor and/or deposited sludge can be removed, so that the accuracy of water quality detection of the water quality sensor can be enhanced.

Abstract: It is an object of the present invention to provide an effective technique for achieving a higher level of water quality control in a water treatment apparatus. Representative water treatment apparatus according to the present invention may include a purifying section, a sterilizing section, a water storing section and a water quality detection sensor. The water quality detection sensor is immersed in the water storing section. The water quality detection sensor not only serves as a means for detecting the quality of water in the water storing section, but also as a means for detecting deposition of biomembrane on the detecting section of the water quality detection sensor due to deterioration of the sterilizing performance of the water storing section. As a result, an efficient water quality control system can be realized.