Vacuum valve control device and vacuum valve

A vacuum valve having a vacuum valve control device for opening and closing a communicating section between a suction pipe communicating with a tank and vacuum discharge pipe communicating with a vacuum source, said vacuum valve comprising:

• a valve body for opening and closing said communicating section;
• a valve operating chamber for accommodating a plunger connected with said valve body;
• a closing force providing means for providing a closing force to said valve body via said valve operating chamber,
• wherein said vacuum valve control device selectively provides an opening force to said valve body via said valve operating chamber, said vacuum valve control device comprising:
• a liquid level detecting diaphragm which resiliently deforms in response to a liquid level in said tank;
• a second plunger directly driven by said liquid level detecting diaphragm;
• a detecting valve being drive by said second plunger;
• a pressure control chamber maintaining a vacuum pressure from a vacuum passage applied thereto when said detecting valve is driven by said second plunger and maintaining an atmospheric pressure from an atmospheric passage applied thereto when said detecting valve is not driven by said second plunger;
• a changeover valve which operates to connect a vacuum pressure from said vacuum passage to said valve operating chamber when said pressure control chamber maintains a vacuum pressure, thereby providing said opening force upon said valve body;
• and
• an opening time adjusting valve for variably releasing a vacuum force introduced into said pressure control chamber, said opening time adjusting valve having an air hole for releasing said vacuum and being compressively deformed to change the section area of said air hole so that an opening time for said vacuum valve can be controlled according to the varying pressure of said pressure control chamber.

A vacuum valve having a vacuum valve control device for by opening and closing a communicating section between a suction pipe communicating with a tank and a vacuum discharge pipe communicating with a vacuum source, said vacuum valve comprising:

• a valve body for opening and closing said communicating section;
• a valve operating chamber for accommodating a plunger connected with said valve body;
• a closing force providing means for providing a closing force to said valve body via said valve operating chamber,
• wherein said vacuum valve control device for selectively provides an opening force to said valve body via said valve operating chamber, said vacuum valve control device comprising:
• a liquid level detecting diaphragm which resiliently deforms in response to a liquid level in said tank;
• a second plunger directly driven by said liquid level detecting diaphragm;
• a detecting valve being driven by said second plunger;
• a pressure control chamber maintaining a vacuum pressure from a vacuum passage applied thereto when said detecting valve is driven by said second plunger and maintaining an atmospheric pressure from an atmospheric passage applied thereto when said detecting valve is not driven by said second plunger;
• a changeover valve which operates to connect a vacuum pressure from said vacuum passage to said valve operating chamber when said pressure control chamber maintains a vacuum pressure, thereby providing said opening force upon said valve body;
• and
• an opening time adjusting valve for releasing a vacuum force introduced into said pressure control chamber, the opening time of said opening time adjusting valve being automatically controlled in accordance with a degree of vacuum in said vacuum discharge pipe.

A vacuum valve control device for controlling operation of a vacuum valve by opening and closing a pipe-shaped connecting section which connects a vacuum discharge pipe in a vacuum condition with a suction pipe for sucking liquid-like materials from a tank, said vacuum valve control device comprising:

• a liquid level detecting pipe whose inside pressure fluctuates in accordance with a liquid level in said tank;
• a pressure adjusting chamber communicating with said liquid level detecting pipe;
• a free-standing damping diaphragm disposed between said liquid level detecting pipe and said pressure adjusting chamber, said damping diaphragm being situated without attachment upon a support portion such that a groove is formed around the periphery of said support portion to quickly release the pressure within the pressure adjusting chamber around the peripheral edge of the damping diaphragm and to quickly close the damping diaphragm in response to a decrease of the pressure inside said liquid level detecting pipe;
• a liquid level detecting diaphragm being resiliently deformed in response to a pressure increase in said pressure adjusting chamber;
• a detection valve controlled by deformation of said liquid level detecting diaphragm;
• and
• a changeover valve being controlled by said detection valve to selectively apply a vacuum pressure and an atmospheric pressure to said vacuum valve.