JPH0685843B2 - Strainer with screen cleaning function - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strainer provided in the middle of a fluid pipe to remove foreign matter in a fluid, and particularly has a function of discharging foreign matter captured by a screen to the outside of the device. Regarding things.

BACKGROUND ART A lot of foreign matters such as carbon and dust are mixed in a fluid, especially steam and its condensate water, and these foreign matters are caused by various valves,
For example, it stuck to the valve opening of the steam trap and caused various problems.

Therefore, conventionally, in order to remove foreign matter in the fluid, Y is generally used.
There is a so-called type strainer. This is provided with a fluid inlet and outlet in the main body, a porous cylindrical screen is placed between the inlet and outlet, and it is provided to discharge foreign substances clogged in the pores of the screen to the outside of the device. It is composed of a discharge valve that is installed.

Problems to be Solved by the Invention When the fluid flowing from the inflow port passes through the screen, the strainer accumulates and removes foreign matters such as dust and carbon contained in the fluid in the pores. If the amount of accumulation increases, the fluid passage area of the screen decreases, and eventually the fluid does not flow. Therefore, foreign matter accumulated by the discharge valve provided under the screen is removed.

However, at this time, the large foreign matter on the screen surface is discharged to the outside of the device by the fluid pressure on the primary side, but the small foreign matter stuck in the pores cannot be removed and remains. The only way to completely remove it was to remove the screen from the body and clean it.

As a result of analyzing the components of foreign matter such as carbon and dust,
It turns out that the main component is iron. In particular, in pipes through which a high-temperature and high-pressure fluid such as steam flows, oxidation of the metal surface is promoted and corrosion is remarkable.

Taking into consideration this point, the technical means of the present invention taken to solve the above-mentioned problems is a strainer including a fluid inlet, a foreign matter capturing screen in the fluid, and an outlet.
The foreign matter capturing screen is formed of an electromagnet, and a separate electromagnet is arranged facing the entire inflow side surface of the screen at a predetermined distance, and a discharge valve is connected to the inflow side of the screen to form a foreign matter formed by the electromagnet. The electromagnet is not magnetized while the capturing screen is magnetized, the outflow valve is kept closed, the electromagnet is magnetized when the screen is demagnetized, and the electromagnet is demagnetized after a predetermined time. When the discharge valve is opened, the control device is arranged so that the discharge valve is opened.

Action During normal operation, the screen is always magnetized, and foreign matter (iron) in the fluid accumulates on the pores of the screen.
Further, when the amount of accumulation increases and the fluid passage area of the screen becomes smaller and the fluid becomes difficult to flow, the magnetization of the screen is cut off and the electromagnet is magnetized. Then, the foreign matter adhering to the surface and pores of the screen is attracted to the electromagnet and adheres to the surface. Thereafter, when the electromagnet is also demagnetized and the discharge valve is opened, foreign matter is freed and blown out of the discharge valve by the action of the flow of the primary pressure and discharged.

Effect Foreign matter adhering to the screen is forcibly removed by the electromagnet, so the screen can be completely cleaned without disassembling it from the main body. Further, since the screen is magnetized, it is possible to remove even small foreign matters that have conventionally passed. Therefore, the valve provided on the secondary side of the strainer operates well without causing clogging of the valve opening.

Example An example showing a specific example of the above technical means will be described. (See FIG. 1) The main body 1 is provided with a fluid inlet 2 and an outlet 3, and porous cylindrical screens 4 and 5 are arranged between the inlet 2 and the outlet 3, and fixed by a screen holder 6. To do. The screens 4 and 5 are formed so that a coil is wound around a part thereof (not shown) to become an electromagnet. Screen 4,
The roughness of the eyes 5 is greater than the outer screen 5 and the inner screen 4
Is rougher.

An exhaust port 7 to the outside of the device is formed in the screen holder 6, and an electric valve 8 as an exhaust valve is connected thereto. Further, on the side surface of the screen holder 6, a connector 13 of a power supply line 12 to a coil (not shown) for magnetizing the screens 4 and 5 is provided.
To provide.

Pressure sensors 9 and 10 are installed on the inflow port 2 side and the outflow port 3 side with respect to the screens 4 and 5, and respective signals from the pressure sensors 9 and 10 are input to a controller 11 so that the differential pressure thereof is constantly checked.

The controller 11, the power supply line 12 to the coil, and the electric valve 8 are connected to each other. The controller 11 accommodates a control device that performs the following functions.

Since the pressure difference between the inlet 2 side and the outlet 3 side is small when the screen is not clogged at the beginning of operation and in normal operation, the controller 11 judges that the screen is normal and the screen 4 is not magnetized. Are placed in a magnetized state. At this time, the motor-operated valve 8 is closed.

The foreign matter (iron content) that has flowed in through the inflow port 2 is removed by the screen 4 when it is large, and the small foreign matter that cannot be removed there is adsorbed by the pores of the screen 5 and the magnetic force. At this time, even a small foreign matter that normally passes through the pores of the screen is attracted and removed because the screen 5 itself is magnetized.

When foreign matter accumulates in the screens 4 and 5 and the accumulated amount increases, the fluid passage area of the screen decreases, and as a result, the pressure on the outlet 3 side becomes lower than that on the inlet 2 side, and the differential pressure is the reference. If it becomes larger than the value, it is judged in the controller 11 that the supply voltage to the screen 5 is cut off and the magnetization is also cut off. At the same time, power is supplied to the screen 4 to magnetize it. Then, the foreign matter attached to the pores of the screen 5 is forcibly attracted to the screen 4 and attached to the surface thereof.

After the screen 4 has been attracted for a certain set time, the magnetization of the screen 4 is also cut off and the motor-operated valve 8 is opened, so that the foreign matter adhering to the surface of the screen 4 or the foreign matter remaining on the screen 5 (other than iron) ) Is also discharged out of the device by the action of the fluid pressure on the primary side. After discharging for a certain period of time, the motor-operated valve 8 is closed and the magnetized states of the screens 4 and 5 are restored.

Here, the pressure difference between the primary side and the secondary side is about 0.3 kg / cm ² or less when the screen is not clogged, and the standard is to judge that it is clogged if it is more than that.

In this embodiment, the screen 4 is not magnetized in the initial stage, but it may be magnetized. Further, the screen 4 may be an ordinary rod-shaped electromagnet having no screen function.

In this embodiment, the pressure sensors 9 and 10 are used to detect the differential pressure across the screens 4 and 5 to switch the magnetization and open / close the motor-operated valve 8. However, the pressure sensors 9 and 10 are used. For example, the switching and the opening / closing of the motor-operated valve 8 may be performed at regular time intervals without the need.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of this embodiment. 1: Main body, 2: Inlet 3: Outlet, 4,5: Screen 8: Motorized valve, 9, 10: Pressure sensor 11: Controller

Claims (1)

[Claims] 1. A strainer comprising a fluid inflow port, a foreign matter capturing screen in the fluid, and an outflow port, wherein the foreign matter capturing screen is formed of an electromagnet, and a predetermined distance is provided facing the entire inflow port side surface of the screen. A separate electromagnet is placed separately, and a discharge valve is connected to the inlet side of the screen.The electromagnet is not magnetized while the foreign substance capturing screen formed by the electromagnet is magnetized, and the discharge valve is closed. A strainer with a screen cleaning function, in which a control device is arranged to keep the state and the electromagnet is magnetized when the magnetization of the screen is cut off, and the discharge valve is opened when the magnetization of the electromagnet is cut off after a predetermined time.