JPS60882A - Ultrapure water production equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] □ This invention relates to an ultrapure water production device. Purity commercial water is used for cleaning water for the electronic industry, water for medicine, and water for nuclear power. Moreover, in recent years, as these industries have become more sophisticated,
Ultrapure water with purity close to theoretically pure water is increasingly required.

Ultrapure water is produced by an ultrapure water production device consisting of a membrane separation device such as an ultrapolar membrane device or a reverse osmosis membrane device, an ion exchange resin device, or a combination of these devices, stored in a storage tank, and then passed through a pipe from the tank. Supply it to the place where it is used.

In general, the operation of these membrane separation devices is controlled by the water level in the storage tank, and when the water level in the storage tank becomes high and the ultrapure water becomes sufficiently strong, the operation of the membrane separation device is interrupted and the operation is stopped at the point of use. When 8 degrees of ultrapure water is taken out and the water level in the tank becomes low, operation will resume. When this operation is stopped, the membrane separator releases pressure h, so for example, if the tip of the discharge pipe of the concentrated water discharged by the membrane separator comes into contact with the outside air, bacteria in the air will come out of the discharge pipe. This can cause the membrane separator to become contaminated with small particles, making it impossible for the membrane separator to produce ultrapure water of the water quality that is titrated at the point of use, and for process chemicals containing water to In addition, once the production equipment becomes contaminated with bacteria, it becomes difficult to produce highly purified water.

For this reason, conventionally, membrane separation equipment is sterilized with all chemicals once a week to prevent bacterial contamination, but since ultrapure water cannot be produced during sterilization, ultrapure water is used at the point of use. be restricted in its use.

In order to avoid this, two membrane separation devices may be installed, and while one is sterilizing, ultrapure water can be produced in the other, but this increases the cost.

Therefore, in the present invention, when the operation of the membrane separation device is stopped, the inside of the device is maintained at a positive pressure, that is, a pressurized state, thereby preventing bacteria from entering quickly. Experimental results show that after sterilization, the device can be maintained in a sterile state for more than 6 months without sterilization, eliminating the need for frequent sterilization and restrictions on the use of ultrapure water at the point of use. Eliminates the waste of installing two units on the device.

Hereinafter, a description will be given with reference to one embodiment shown in the drawings.

1 is a membrane separation device such as an ultrapolar filtration membrane device or a reverse osmosis membrane device, and raw water that has been sufficiently pretreated with an ion exchange resin device is stored in a water supply tank, and this raw water is passed through a water supply pipe and a water supply pump 3.
The water is pressurized and supplied to the supply side of the membrane separator, permeates through the permeation membrane l' built into the device, and the water that comes out on the permeation side is stored as ultrapure water in the storage tank S via the supply pipe 4, and from there. Supply pipe 6
will lead you to point of use 7.

A level switch g that detects the internal water level enters the storage tank 3A, and when the water level of the ultrapure water in the tank rises, the water supply pump 3 is stopped and the operation of the device l is interrupted, and the water level is When the water level drops to a certain level, the water supply pump is activated and the equipment is restarted.

As mentioned above, in this state, when the device is stopped, the pressure inside the device is not in an open state, and the tip of the skewer pipe 7, etc., which is connected to the supply side of the device, If it is exposed to the atmosphere, bacteria from the parasitic system will quickly enter the system, contaminating the entire device.

Therefore, non-invention is replenishment 11μ, large opening/closing valve v1 for discharge goods Wa
, v2 are provided, and the water supply pipe is provided with an on-off valve v3 and a pressure switch io'6 between the water supply pump 3 and the membrane separation device l,
When stopping the operation of the device 1, first close the on-off valves V+ and V2, and then, after a while, stop the water supply pump 3 and close the on-off valve V8f, thereby keeping the inside of the device at positive pressure and opening the tank. The pressure switch 10 monitors the internal pressure of the device until the water level inside the device falls to a certain level and the device resumes operation. When the internal pressure drops to the allowable limit, it is detected and the pressure switch 10
When the on-off valve v3 is opened, the water supply pump 3 is driven at the same time, and when the internal pressure of the apparatus rises, the water supply pump Jf is stopped and the on-off valve v5 is closed, thereby maintaining the internal pressure of the apparatus.

For this purpose, the on-off valves V+, V2, and VB are electrically connected to the control device l/, together with the motor of the water supply pump J, the level switch g1, the pressure switch 10, and the control device uses an automatic -fff such as an electromagnetic type. When receiving a signal to stop the operation of the device, the on-off valves v1 and V2'ir are closed,
Stopping the motor of the water supply bonder and opening the on-off valve v8 is the on-off valve V.
+ After closing V2, this is done after a predetermined time has elapsed using a timer, or when the pressure switch io detects the upper limit pressure. When the internal pressure drops to the lower limit of the pressure switch/θ (for example, θ, !; 14/cM), the control device operates the on-off valve V until it returns to the upper limit of the pressure switch.
, f opens and drives the water pump motor.

In addition, when the water level in the storage tank drops, the level switch g sends a request signal to the control device l/ to operate the membrane separator, and the control device opens all the shut-off valves that are closed and starts water supply. Drive the pump motor to restart the membrane separation device.

As is clear from the above, in the present invention, when the device is stopped, the interior, which is closed by the on-off valves v, , v2, and vi, is maintained in a pressurized state, and this pressure allows bacteria to enter the interior. It is possible to maintain a sterile state without frequent sterilization, and to prevent bacterial contamination of the membrane separation device in ultrapure water production equipment.

In addition to implementing the present invention in a newly installed device, the present invention can also be implemented by modifying an existing device. Also, pressure switch I
O is not limited to being provided in the water supply pipe, but may be provided between the on-off valve of the supply pipe or drain pipe and the membrane separation device.

[Brief explanation of drawings]

The drawing is a flow sheet of one embodiment of the present invention, in which l is a membrane separation device, l' is its permeable membrane, ko is a water supply pipe, 3 is a water supply pump, q is a supply pipe, 9 is a drain pipe, IO is the pressure detection means 6. b Pressure switch, 1/ is control device, V+, V
2, vs indicates an on-off valve.

Claims (1)

[Claims] (1) In an ultrapure water production device that has a membrane separation device with a built-in permeation membrane, there is a water supply pump that pressurizes raw water to the water supply pipe connected to the supply side of the membrane separation device and supplies it to the membrane separation device, and a water supply pump. and a drain pipe for concentrated water discharged from the supply side of the membrane separator;
An on-off valve is installed in each of the supply pipes that lead the ultrapure water obtained to the permeate side of the membrane separator, and at least one of these three water supply pipes, drain pipes, and supply pipes is equipped with an on-off valve and an on-off valve for the membrane separator. A pressure detection means is provided in between, and when the three on-off valves, the water supply pump motor, and the pressure detection means receive a signal to stop the water supply pump, they close the on-off valves of the supply pipe and the drain pipe, and then close the water supply pipe. When the on-off valves are closed and the water supply pump motor is stopped, and when the three on-off valves are closed and the pressure detection means detects a drop in the pressure of the membrane separator, the water supply pipe on-off valve is opened and the water supply pump motor is stopped. An ultrapure water production device characterized by being connected to a control device that drives a motor. (2. In the device according to claim (1), after closing the on-off valves of the supply pipe and drain pipe, the on-off valve of the water supply pipe is turned off and the motor of the water supply pump is stopped due to the pressure around the membrane separator. An ultrapure water production device in which a pressure detection means detects the height of #) and causes a control device to perform the operation.