JP3473866B2 - Membrane deaerator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane deaerator for removing dissolved oxygen from water using a gas-liquid separation membrane.

[0002]

2. Description of the Related Art In recent years, corrosion of tap water supply pipes in high-rise buildings has become a problem, and in order to prevent corrosion, a membrane deaerator is installed at the water supply source to remove oxygen that causes corrosion. It is practiced to prevent corrosion by supplying steam. In that case, the amount of water used varies greatly depending on the time of day, but since it is necessary to always be able to supply water, the deaerator operates continuously for 24 hours, and the amount of water used is small. In a time zone, running costs are increased due to wasteful driving.

Therefore, an integrating flowmeter is inserted in the connecting pipe,
When the amount of water flowing from the water tank to the water supply pipe reaches the first set value, deaeration operation is started, and the amount of water flowing from the water supply pipe to the water tank reaches the second value.
Control system of the membrane degassing device in the building water supply piping structure that stops the degassing operation when the set value of
28467) was proposed. With this system, when the water usage is low, the degassing operation is stopped, and when the raw water is replenished to the water tank and the dissolved oxygen concentration in the water tank rises, the degassing operation is started, but when the water usage is low If the operation interval until the next degassing becomes too long, oxygen is redissolved in the degassed water, the dissolved oxygen concentration rises, and corrosion cannot be prevented. Further, since the degassing operation is performed depending on the amount of water used, even if the dissolved oxygen concentration rises due to raw water replenishment, water may be supplied as it is.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a membrane deaerator capable of eliminating unnecessary deaerating operation while preventing corrosion of water supply piping.

[0005]

Means for Solving the Problems A water tank to which a raw water supply line for replenishing raw water is connected, a replenishing device provided on the raw water supply line, a membrane degassing module having a vacuum generator, and a circulation pump in the middle of the tank. Is provided, a water supply pipe for supplying water from the water tank to the membrane degassing module, a water supply pipe for supplying degassed water from the membrane degassing module to a water use location, and a connection pipe for connecting the water supply pipe and the water tank, In a membrane degassing device that performs degassing operation by operating a vacuum generator and a circulation pump, an operation control device that has a timer and performs degassing operation at predetermined intervals is provided, and degassing operation is performed at predetermined intervals.

In addition, when the raw water is replenished or when the value detected by a dissolved oxygen concentration meter for detecting the dissolved oxygen concentration in water provided at a proper position in the deaerator is above a predetermined value, the deaeration operation is performed to dissolve the dissolved oxygen. When the concentration becomes lower than the predetermined value, the degassing operation is stopped.

[0007]

[Operation] Water is used by performing deaeration operation at predetermined intervals, deaeration operation when replenishing raw water to the water tank, and deaeration operation according to the dissolved oxygen concentration in water in the deaerator. It is possible to prevent useless operation in a time zone when the amount is small, and to prevent an increase in dissolved oxygen concentration. When controlling the degassing operation by time, it is possible to prevent wasteful operation when water is not used by stopping the degassing operation, and even if there is no water used Therefore, it is possible to prevent the dissolved oxygen concentration in the deaerator from increasing. Also, when deaeration operation is performed when replenishing raw water to the water tank, the dissolved oxygen concentration in the water tank rises due to the replenishment of raw water, but if deaeration operation is performed, the deaeration water immediately after deaeration treatment will be placed in the water supply pipe. Therefore, the dissolved oxygen concentration in the water supply pipe can be kept at a low value. Furthermore,
By detecting the dissolved oxygen concentration and continuing the degassing operation until the dissolved oxygen concentration is equal to or higher than a predetermined value, the degassing can be reliably performed.

[0008]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows the flow of the membrane degassing apparatus, and FIG. 2 shows a time chart. When the water level detecting device (9) for detecting the water level in the water tank (1) outputs that the water level in the water tank has dropped, the replenishing device is inserted in the middle of the raw water supply line (13) for replenishing the raw water. The make-up water solenoid valve (7) is opened, and raw water is replenished until it reaches a certain water level. The water accumulated in the water tank (1) passes through a water supply pipe (4) provided with a circulation pump (3) in the middle of the pipe, and then to a membrane degassing module (5) connected to a vacuum generator (11). The water is sent to be deaerated, and water is supplied to each water use place through the water supply pipe (6). A dissolved oxygen concentration meter (2) for detecting a dissolved oxygen concentration in water is branched from a downstream side of a circulation pump (3) provided in a water supply pipe (4), and a sample water pipe connected to an upstream side of the pump. It is installed in (14). By providing this sample water pipe (14), the water conventionally discharged for each dissolved oxygen concentration meter can be circulated and there is no waste. Connection pipe (10) between water supply pipe (6) and water tank (1)
The water in the water tank (1) is supplied to the place of use of water through the connecting pipe (10) and the water supply pipe (6) while the deaeration operation is stopped. On the contrary, during the deaeration operation, the water is directly supplied to the place where the water is used through the water supply pipe (6), and the surplus deaerated water is returned to the water tank (1) through the connection pipe (10). The operation control device (8) has an interval timer (1
2), circulation pump (3), vacuum generator (1
1), the water level detector (9), and the dissolved oxygen concentration meter (2) are connected by signal lines. Further, the operation control device (8) is preset with a predetermined degassing operation time (A) for continuing the operation for a predetermined time (for example, 5 minutes) and a predetermined dissolved oxygen concentration (for example, 0.5 ppm), and the interval timer is set. Is set to a deaeration operation stop time (B) for stopping the deaeration operation for a predetermined time (for example, 3 minutes), and the deaeration operation is performed at predetermined intervals. The set time and the set value of the dissolved oxygen concentration are not limited to this and may be arbitrary. For example, the set value of the dissolved oxygen concentration may be set to any value as long as it does not cause a corrosion problem and is 2 ppm or less.

When the water level in the water tank (1) is lowered and the water level detection device (9) transmits a raw water replenishment signal, the replenishment water solenoid valve (7) is opened to start the raw water replenishment and the operation control device. In (8), the vacuum generator (11) and the circulation pump (3) are operated to start deaeration operation, and the operation time of the membrane deaeration device is counted by the timer in the operation control device (8). Although the dissolved oxygen concentration in the water tank increases due to the replenishment of raw water, the degassing operation is performed, so the membrane degassing module (5)
The degassed water degassed in (1) is directly supplied to the water use place and used.

A description will be given below with reference to FIG. After the water level in the water tank (1) rises and the supply of raw water is completed, the degassing operating time counted by the timer is equal to or longer than the predetermined degassing operating time (A) and the dissolved oxygen concentration is equal to or lower than the preset predetermined concentration. When this happens, the deaeration operation is stopped (state). At the same time, the interval timer (12) is activated. If the deaeration operation stop time (B) is output by the interval timer (12) without the raw water supply being performed and the deaeration operation not being performed, the operation control device (8) performs the deaeration operation. Start (state of). Specified degassing operation time (A)
When the dissolved oxygen concentration is equal to or lower than the predetermined dissolved oxygen concentration at the time of performing the degassing operation of, the degassing operation is stopped, but the degassing operation of the predetermined degassing operation time (A) is performed by re-dissolving oxygen and supplementing raw water. Even after the above, when the dissolved oxygen concentration exceeds the predetermined dissolved oxygen concentration, the degassing operation is further continued until the dissolved oxygen concentration becomes equal to or lower than the predetermined value (state). When the raw water supply signal to the water tank (1) is input to the operation control device, the deaeration operation is started regardless of the deaeration operation stop time (B) (state).

The following can be mentioned as preferred embodiments of the present invention. A dissolved oxygen concentration is branched from a circulation pump downstream side provided in a water supply pipe, and is provided in a sample water pipe connected to the pump upstream side.

[0012]

The degassing operation can be stopped when the water with a high dissolved oxygen concentration is not supplied and the degassing operation is unnecessary, so that the running cost of the membrane degassing apparatus can be suppressed and the efficiency can be improved. Operation can be performed, and the corrosion prevention effect can be maintained.

[Brief description of drawings]

FIG. 1 is a flow sheet of an embodiment of the present invention.

FIG. 2 is a time chart of an embodiment of the present invention.

[Explanation of symbols]

1 aquarium 2 Dissolved oxygen concentration meter 3 circulation pumps 4 water supply piping 5 Membrane degassing module 6 water supply piping 7 Replenishment device (make-up water solenoid valve) 8 Operation control device 9 Water level detector 10 connection piping 11 Vacuum generator 12 Interval timer 13 Raw water supply line 14 sample water piping A specified degassing operation time B degassing operation interval time

Front page continuation (72) Inventor Yoshihiro Ozawa 3-4-7 Nishishinjuku, Shinjuku-ku, Tokyo Kurita Industry Co., Ltd. (56) Reference JP-A-6-79259 (JP, A) Mitsuihei 4-137705 (JP, U) Utility model registration 3003429 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 1/20 C02F 1/00 B01D 19/00-19/04

Claims (3)

(57) [Claims] 1. A water tank to which a raw water supply line for replenishing raw water is connected, a replenishing device provided on the raw water supply line, a membrane degassing module having a vacuum generator, and a circulation pump provided midway, A water supply pipe for supplying water from the water tank to the membrane degassing module, a water supply pipe for supplying degassed water from the membrane degassing module to a place where water is used, and a connecting pipe connecting the water supply pipe and the water tank are provided, and a vacuum generator and a circulation system are provided. A membrane degassing apparatus that performs degassing operation by operating a pump , comprising an operation control device that performs degassing operation at predetermined intervals . 2. The membrane degassing apparatus according to claim 1,
The operation control device performs deaeration operation even when replenishing raw water.
A membrane degassing device characterized in that 3. The membrane degassing apparatus according to claim 1 or 2 , wherein the operation control device performs degassing operation at the time of replenishing raw water or at predetermined intervals, and dissolves oxygen in water provided in a proper place in the degassing apparatus. If the detected value of the dissolved oxygen concentration meter that detects the concentration is less than or equal to a predetermined value, deaeration operation is stopped, and if it is greater than or equal to a predetermined value, operation control is performed to continue the deaeration operation until it falls below a predetermined value Membrane deaerator characterized by being a thing.