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Vacuum valve control device and vacuum valve

Usually, sewage discharged from every home flows to a sewage disposal plant by the action of natural flow. However, in this natural flow type sewage collection system, the construction of sewer pipes is restricted by geography and the condition of the ground, and further the drain tends to be stopped up. For this reason, recently, attention has been given to a vacuum type sewage collection system in which sewage discharged from every home is forcibly transported by the action of vacuum.

This vacuum type sewage collection system includes: a vacuum valve unit in which sewage discharged from each home is stored when it flows by the action of natural flow; and a vacuum station by which sewage is collected from the vacuum valve unit through a vacuum pipe.

A vacuum valve unit is disclosed, for example, in U.S. Pat. No. 5,069,243. The vacuum valve unit disclosed in the above patent includes: a suction pipe, one end of which is dipped in sewage in the sewage tank; a vacuum valve, the pipe-shaped communicating portion of which is connected with the other end of the suction pipe; and a vacuum discharge pipe connected with the communicating portion, wherein this vacuum discharge pipe is connected with a vacuum pump disposed in a vacuum station through a vacuum pipe. In the vacuum valve, the pipe-shaped communicating portion can be opened and closed when a valve body disposed in the pipe-shaped communicating portion is operated. The vacuum pipe is maintained to be in a vacuum condition at all times by the action of the vacuum pump through the vacuum pipe. When a predetermined amount of sewage is stored in the sewage tank, the valve body of the vacuum valve is opened by a pressure difference between the vacuum in the vacuum discharge pipe and the atmosphere, so that the pipe-shaped communicating portion can be opened. Due to the foregoing, the vacuum discharge pipe in a vacuum condition is communicated with the suction pipe, so that sewage in the sewage tank is sucked into the vacuum discharge pipe by the action of vacuum, and transported to the vacuum station through the vacuum pipe.

The valve body disposed in the communicating portion of the vacuum valve usually closes the communicating portion. When the valve operating chamber is put into a vacuum condition, the valve body is pulled so that the communicating portion can be opened. The vacuum condition in the valve operating chamber is controlled by the vacuum valve control device.

This vacuum valve control device is connected with a liquid level detecting pipe, the lower end of which is dipped in the sewage in the sewage tank. When the liquid level of sewage is changed, the pressure in the liquid level detecting pipe is changed, so that a liquid level detecting diaphragm provided in the vacuum valve control device is resiliently deformed. Due to the deformation of the liquid detecting diaphragm, a detecting valve for introducing a vacuum into the vacuum valve control device is operated. Therefore, vacuum is activated on a changeover valve disposed in the vacuum control valve. Due to the foregoing, the changeover valve can be changed over, so that the vacuum discharge pipe is communicated with the valve operating chamber of the vacuum valve. Accordingly, this valve operating chamber is put in a vacuum condition. When the valve operating chamber is put in a vacuum condition, the valve body is pulled, and the communicating portion is opened.

As a result of the foregoing, the vacuum discharge pipe in a vacuum condition is communicated with the suction pipe, so that the inside of the suction pipe is also put in a vacuum condition. Accordingly, sewage in the sewage tank is quickly sucked into the suction pipe and vacuum discharge pipe. Then the sewage is transported into a sewage collection tank in the vacuum station through the vacuum pipe.

When sewage in the sewage tank is sucked in a moment, the liquid level detecting diaphragm of the vacuum valve control device gradually returns to the original condition. Due to the foregoing, the operation of the detecting valve is released, and the communication between the inside of the vacuum valve control device and the vacuum discharge pipe is intercepted, and at the same time the atmosphere is introduced into the vacuum valve control device. Then the changeover valve is changed over, so that the atmosphere is introduced into the valve operating chamber of the vacuum valve.

2012-01-19

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