Abstract: A spiral wound membrane element allowing back wash reverse filtration at 0.05 MPa to 0.3 MPa is employed for a spiral wound membrane module. Air injection of injecting air of not more than 0.3 MPa into a permeate outlet of the spiral wound membrane module from a pressurized air feeder through a pipe, back wash reverse filtration with permeate and flushing with raw water are performed as recovery of a filtration velocity. Another spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. Raw water into which bubbles are diffused by an air diffuser is fed to the spiral wound membrane element stored in a pressure vessel. Part of the raw water is axially fed through the spiral wound membrane element, discharged from a raw water outlet of the pressure vessel and thereafter returned to a raw water tank through a pipe.

Abstract: A spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. The flow rate of permeate in filtration of the spiral wound membrane element is preferably set to 0.5 to 2.0 m3/m2/day, and the filtration time is preferably set to 10 to 300 minutes. The flow rate of wash water in washing is preferably set to 1.0 to 4.0 m3/m2/day, and the washing time is preferably set to 10 to 300 seconds. In such ranges, the ratio of the permeate volume in filtration to the permeate volume in back wash reverse filtration is set to be not more than 600.

Abstract: A spiral separation membrane element effective in reducing the pressure loss around core tube perforated parts, which is problematic especially in low-pressure operations.

Abstract: A spiral separation membrane element which can attain a reduced pressure loss in the permeation-side passage and is effective especially when the feed-side pressure is low, is disclosed. The spiral separation membrane element comprises a perforated core tube and, wound therearound, one or more separation membranes, one or more feed-side passage materials, and one or more permeation-side passage materials, wherein the permeation-side passage materials each have warps 1 extending almost parallel with the direction of flow of a permeated liquid and wefts 2 fixed to the warps 1, a ratio of a pitch (width of each warp+distance between the opposed sides of adjacent warps) to a distance between the opposed sides of adjacent warps (w2/w1) is 1.1/1 to 3/1, and a ratio of a thickness of the passage material to a distance between the opposed sides of adjacent warps (t/w1) is 0.25/1 to 1.25/1.

Abstract: A spiral separation membrane element which can attain a reduced pressure loss in the feed-side passage and is difficult to encounter the problem of flow inhibition or clogging in the feed-side passage. The spiral separation membrane element comprises a perforated cored central tube and, wound therearound, one or more separation membranes, one or more feed-side passage materials, and one or more permeation-side passage materials, wherein the feed-side passage materials each have warps 1 extending almost parallel with the direction of flow of a feed liquid and wefts 2 which are thinner than the warps 1, and a ratio of a pitch of the warps L1 to a pitch of the wefts L2 being from 1/1.5 to 1/6.

Abstract: A spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. In filtration running, raw water introduced from a raw water inlet of a pressure vessel is subjected to dead end filtration, and permeate is taken out from a permeate outlet. In washing, wash water containing a chemical having a contaminant separating function is introduced from an end of a water collection pipe through the permeate outlet for performing back wash reverse filtration with a back pressure of 0.05 to 0.3 MPa. The filtration running is temporarily stopped for maintaining the pressure vessel in a state sealed with the raw water and the permeate for a prescribed time. Thus, contaminants adhering to the membrane surface of the spiral wound membrane element are separated. A treatment system is formed by connecting units comprising spiral wound membrane modules in parallel with each other.

Abstract: In a multistage osmosis treatment method including: subjecting liquid to reverse osmosis treatment in a first-stage reverse osmosis separation module (31); adding an alkali agent to the obtained permeated water (5) to adjust a pH value of the permeated water (5) in an alkaline region; and further subjecting the permeated water (5) to reverse osmosis treatment in second and subsequent stage reverse osmosis separation modules (32), the supply water (5) to the second-stage reverse osmosis separation module (32) is subjected to at least one treatment selected from deferrization, demanganization, decarboxylation, and addition of a chelator and a scale inhibitor. Because of this, multistage reverse osmosis treatment is provided, in which the separation performance of the second and subsequent stage reverse osmosis membrane modules is enhanced, and liquid can be separated and purified to a high degree, and boron and the like that are not dissociated in a neutral region can be separated at a high blocking ratio.

Abstract: A spiral wound membrane element allowing back wash reverse filtration at 0.05 MPa to 0.3 MPa is employed for a spiral wound membrane module. Air injection of injecting air of not more than 0.3 MPa into a permeate outlet of the spiral wound membrane module from a pressurized air feeder through a pipe, back wash reverse filtration with permeate and flushing with raw water are performed as recovery of a filtration velocity. Another spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. Raw water into which bubbles are diffused by an air diffuser is fed to the spiral wound membrane element stored in a pressure vessel. Part of the raw water is axially fed through the spiral wound membrane element, discharged from a raw water outlet of the pressure vessel and thereafter returned to a raw water tank through a pipe.

Abstract: A spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. The flow rate of permeate in filtration of the spiral wound membrane element is preferably set to 0.5 to 2.0 m3/m2/day, and the filtration time is preferably set to 10 to 300 minutes. The flow rate of wash water in washing is preferably set to 1.0 to 4.0 m3/m2/day, and the washing time is preferably set to 10 to 300 seconds. In such ranges, the ratio of the permeate volume in filtration to the permeate volume in back wash reverse filtration is set to be not more than 600.

Abstract: A spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. In filtration running, raw water introduced from a raw water inlet of a pressure vessel is subjected to dead end filtration, and permeate is taken out from a permeate outlet. In washing, wash water containing a chemical having a contaminant separating function is introduced from an end of a water collection pipe through the permeate outlet for performing back wash reverse filtration with a back pressure of 0.05 to 0.3 MPa. The filtration running is temporarily stopped for maintaining the pressure vessel in a state sealed with the raw water and the permeate for a prescribed time. Thus, contaminants adhering to the membrane surface of the spiral wound membrane element are separated. A treatment system is formed by connecting units comprising spiral wound membrane modules in parallel with each other.

Abstract: An electronically controlled power steering system comprises a vehicle speed sensor, a steering wheel angle sensor, a power steering gear including a control valve, a bypass valve for regulating a flow rate of hydraulic fluid supplied to the control valve of the power steering gear in response to a control signal generated by a controller. The controller is operative responsive to sensor output signals of the sensors for generating the control signal. With the controller, the control signal is varied in response to the vehicle speed and the steering wheel angle when the steering wheel angle is less than a predetermined value, but this varying tendency of the control signal in response to the steering wheel angle is restrained when the steering wheel angle is not less than the predetermined value.

Abstract: A suspension control system employs a road sensor monitoring road roughness or smoothness and producing a road condition indicative signal. The control system also employs other sensor or sensors for monitoring at least one preselected suspension control parameter, such as vehicle speed, steering angular variation and so forth, other than road roughness. The suspension switches between relatively hard and relatively soft characteristics based on the preselected suspension control prameters. In order to make suspension control more precisely suited to the vehicle driving conditions, the control characateristics of the suspension system are adjusted depending upon the road condition.