Abstract: A liquid treating device includes a liquid guide cylinder having liquid suction and ejection ports, a liquid supply unit that supplies liquid to the liquid suction port, a pumping-up unit that is provided within the liquid guide cylinder and suctions liquid from the liquid suction port and ejecting liquid from the liquid ejection port, a liquid ejection space part that enlarges liquid, which has been ejected from the liquid ejection port by the pumping-up unit, in an upper part of a closed tank, a gas supply unit that supplies gas in the liquid ejection space part under pressure, a reflux passage that circulates liquid from the liquid ejection space part through space between the tank and the liquid guide cylinder to a lower part of the liquid guide cylinder, and treated liquid taking-out piping that takes out treated liquid from a lower part of the tank to an exterior.

Abstract: A liquid treating device includes a liquid guide cylinder having liquid suction and ejection ports, a liquid supply unit that supplies liquid to the liquid suction port, a pumping-up unit that is provided within the liquid guide cylinder and suctions liquid from the liquid suction port and ejecting liquid from the liquid ejection port, a liquid ejection space part that enlarges liquid, which has been ejected from the liquid ejection port by the pumping-up unit, in an upper part of a closed tank, a gas supply unit that supplies gas in the liquid ejection space part under pressure, a reflux passage that circulates liquid from the liquid ejection space part through space between the tank and the liquid guide cylinder to a lower part of the liquid guide cylinder, and treated liquid taking-out piping that takes out treated liquid from a lower part of the tank to an exterior.

Abstract: According to the present invention, the mechanical seal unit for pumps including a fixed seal ring facing a lower pressure space and a rotatable seal ring facing a higher pressure space, comprises: at least one outlet groove disposed on a slidable seal face of the fixed seal ring and open exclusively to the lower pressure space; and at least one inlet groove disposed on a slidable seal face of the rotatable seal ring and open exclusively to the higher pressure space such that the inlet groove and the outlet groove partially meet to communicate with each other to form a fluid release passage at a certain point of rotation of the rotatable ring relative to the fixed ring. Otherwise the outlet and inlet grooves may be disposed on the rotatable ring and the fixed ring, respectively, to obtain the same effect.