Patent Publication Number: US-2011052414-A1

Title: Apparatus for Controlling a Pump

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for controlling a pump used in a sewage tank. 
     2. Related Prior Art 
     A tank is often used to contain sewage. A pump is often used in the tank to control the level of the sewage under an upper limit. A controller is often used to control the pump. When the level reaches the upper limit, the controller turns on the pump to pump the sewage out of the tank. Installation and maintenance of the controller are however troublesome and time-consuming. In addition, the controller could soon malfunction after some time of use. 
     The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art. 
     SUMMARY OF THE INVENTION 
     It is an objective of the present invention to provide a pump with a controller that can easily be installed and maintained. 
     It is another objective of the present invention to provide a pump with a reliable controller. 
     To achieve the foregoing objectives, the controller includes a sensor unit and a buoy unit. The sensor includes a base, a cylinder extended from a lower side of the base, a micro-switch provided on the base, a ferromagnetic tag connected to the micro-switch and a switch provided on the base. The switch is connected to the micro-switch on one hand and to the pump on the other hand. The buoy unit includes a buoy, a rod inserted through the buoy and a magnet connected to the rod. The rod is movably inserted in the sensor unit through the cylinder so that the magnet attracts the ferromagnetic tag to actuate the micro-switch when the level of sewage reaches an upper limit and that the magnet releases the ferromagnetic tag when the level of sewage reaches a lower limit. 
     Other objectives, advantages and features of the present invention will be apparent from the following description referring to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be described via detailed illustration of the preferred embodiment referring to the drawings. 
         FIG. 1  is a cross-sectional view of a sewage tank equipped with a pump and a controller according to the preferred embodiment of the present invention. 
         FIG. 2  is an exploded view of the controller shown in  FIG. 1 . 
         FIG. 3  is a cutaway view of the controller shown in  FIG. 1 . 
         FIG. 4  is a cutaway view of the controller shown in  FIG. 1 . 
         FIG. 5  is a perspective view of the control shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , there is shown a tank  7  for containing sewage. In the tank  7 , there are provided a pump  6  and a controller for controlling the pump  6 . When the level of sewage in the tank  7  reaches an upper limit, the controller turns on the pump  6  to pump some of the sewage out of the tank  7 . When the level sewage in the tank  7  reaches a lower limit, the controller turns off the pump  6  to stop pumping the sewage out of the thank  7 . 
     Referring to  FIGS. 2 and 5 , the controller includes a sensor unit  4  and a buoy unit  5  according to the preferred embodiment of the present invention. The sensor unit  4  includes a base  10 , a micro-switch  1  provided on the base  10 , a ferromagnetic tag  8  connected to a trigger of the micro-switch  1 , a switch  11  provided on the base  10  and a cover  3  for covering the micro-switch  1 , the ferromagnetic tag  8  and the switch  11 . The switch  11  is electrically connected to the micro-switch  1  on one hand and to the pump  6  on the other hand. The base  10  includes a cylinder  12  extended from a lower side thereof. The sensor unit  4  is securely provided in the tank  7 . 
     The buoy unit  5  includes a buoy  5 , a rod  2  and a magnet  22 . The rod  2  is inserted through the buoy  51 . The rod  2  includes a slide  21  formed at an upper end thereof. The size of the slide  21  is larger than the remaining portion of the rod  2 . The magnet  22  is located in an aperture defined in the slide  21  before the slide  21  is movably inserted in the sensor unit  4  through the cylinder  12 . A screw  9  is driven into the cylinder  12 , thus keeping the slide  21  within the sensor unit  4 . A ring  41  is secured to a lower end of the rod  2 . 
     Referring to  FIG. 3 , when the level of the sewage in the tank  7  reaches the upper limit, the buoy unit  5  goes up accordingly so that the magnet  22  reaches and attracts the ferromagnetic tag  8 , thus actuating the micro-switch  1 . The micro-switch  1  sends a signal to the switch  11  which in turn actuates the pump  6  to pump some of the sewage out of the tank  7 . 
     Referring to  FIG. 4 , the level of the sewage in the tank  7  goes down as some of the sewage is pumped out of the tank  7 . Accordingly, the buoy unit  5  goes down so that the magnet  22  releases the ferromagnetic tag  8 , thus stopping the micro-switch  1 . Therefore, the switch II turns off the pump  6  to stop pumping the sewage out of the tank  7 . 
     The present invention has been described via the detailed illustration of the preferred embodiment. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims.