Patent Abstract:
A drainage device for draining liquid out of a closed chamber includes an air cylinder, a driving assembly, a first channel, a second channel, a first sealing assembly, a second sealing assembly, and a controller. The air cylinder includes a main body defining a receiving chamber, an action piston positioned in the receiving chamber of the main body, and a connecting rod connected to the action piston. The main body defines a liquid inlet and a liquid outlet, both of which communicate with the receiving chamber, and the presence of a fixed piston with a seal in each of the inlet and outlet creates a double-acting one-way valve when the action piston is moved up and down.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to two co-pending U.S. patent applications, which are: application Ser. No. 13/242,011, application Ser. No. 13/242,006, and all entitled “DRAINAGE DEVICE FOR CLOSED CHAMBER CONTAINING LIQUID”. In this co-pending applications, the inventors are Yang et al. Such co-pending applications have the same assignee as the present application. The disclosure of the above two identified applications are incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure generally relates to drainage devices, and particularly, to a drainage device for draining liquid out of a closed chamber. 
     2. Description of the Related Art 
     In the discharge of sewage, sewage is generally sucked into a container to be purified by a water suction cleaner, and then discharged outside. The sewage suction cleaner includes a closed chamber and an air pump. The air pump creates a certain degree of vacuum in the closed chamber. Under the negative air pressure, the sewage is pushed into the closed chamber. However, when discharging the sewage, outside air will flow into the closed chamber via an outlet, and thus the degree of vacuum of the closed chamber is decreased. As a result, the air pressure difference between the inside and the outside of the closed chamber is decreased, and sewage is not forced as strongly into the closed chamber. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a sectional view of an embodiment of a drainage device in a first state. 
         FIG. 2  is a sectional view of the drainage device of  FIG. 1  in the first state with a receiving chamber full of liquid. 
         FIG. 3  is a sectional view of the drainage device of  FIG. 1  in a second state. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an embodiment of a drainage device  100  includes an air cylinder  20 , a driving assembly  30 , a first sealing assembly  40 , a second sealing assembly  50 , and a controller  60 . 
     A closed chamber  10  defines a fluid channel  12  and a gas channel  14  in the top end, and a slag discharge hole  16  in the bottom end of the closed chamber  10 . The closed chamber  10  further includes a sealing cover  18  for sealing the slag discharge hole  16 . The fluid channel  12  is used for liquid flow, and is equipped with a flow control valve (not shown). The gas channel  14  is connected to an air pump (not shown) for producing a certain degree of vacuum in the closed chamber  10 . 
     The air cylinder  20  is positioned in the closed chamber  10 , and includes a main body  21 , an action piston  23  positioned in the main body  21 , and a connecting rod  25  connected to the action piston  23 , a first channel  217 , and a second channel  219  opposite to the first channel  217 . The main body  21  is substantially cylindrical, and defines a receiving chamber  211 . One end of the main body  21  defines a liquid inlet  213  and a liquid outlet  215  communicating with the receiving chamber  211 , and the other end of the main body  21  is hermetically sealed. The liquid inlet  213  is opposite to the liquid outlet  215 . The first channel  217  communicates with the liquid inlet  213 , and the second channel  219  communicates with the liquid outlet  215 . The first channel  217  is below the level of the liquid of the closed chamber  10 . The liquid in the receiving chamber  211  may be discharged outside the closed chamber  10  via the second channel  219 . 
     The action piston  23  is movably received in the receiving chamber  211 , and forms a sealing surface  231  against a sidewall  2111  of the main body  21 , and a resisting surface  233  adjacent to the liquid inlet  213 . The action piston  23  separates or segregates the receiving chamber  211  into a first chamber  2113  and a second chamber  2115 . The first chamber  2113  communicates with the liquid inlet  213  and the liquid outlet  215 . The action piston  23  is fixed to the bottom of the connecting rod  25 , which extends through the top end of the main body  21 . 
     The driving assembly  30  includes a receiving body  31 , a drive piston  33  movably received in the receiving body  31 , and a drive rod  35 . The receiving body  31  is positioned on the outer surface of the closed chamber  10 . The drive rod  35  connects the drive piston  33  to the connecting rod  25 . 
     The first sealing assembly  40  is positioned in the first channel  217 , and includes a fixed piston  41 , a flexible member  43 , and a filter  45 . The flexible member  43  and the filter  45  are positioned on opposite sides of the fixed piston  41 , and the flexible member  43  is closer to the liquid inlet  213 . The fixed piston  41  defines a plurality of permeable holes (not shown), so that any liquid in the closed chamber  10  can flow to the receiving chamber  211  via the permeable holes. The flexible member  43  is attached to the inner surface of the first channel  217  in order to seal the first channel  217 . In the illustrated embodiment, the flexible member  43  is a circular silicone mat, and the filter  45  is a metal mesh filter, and functions as a large-scale filter of the liquid flowing into the receiving chamber  211 . 
     The second sealing assembly  50  is positioned in the second channel  219 , and includes a fixed piston  51  and a flexible member  53 . The fixed piston  51  has a similar structure and function to those of the fixed piston  41 . The flexible member  53  has a similar structure and function to those of the flexible member  43 . 
     The controller  60  includes a sensor  61  positioned beneath the surface of the liquid in the closed chamber  10 . The controller  60  monitors the level of any liquid in the closed chamber  10  by means of the sensor  61  and controls the movements of the driving assembly  30 . 
     In assembly of the drainage device  100 , the air cylinder  20  is positioned in the closed chamber  10 , with the liquid inlet  213  and the liquid outlet  215  being immersed in the liquid of the closed chamber  10 . The first sealing assembly  40  is positioned in the first channel  217 , and the second sealing assembly  50  is positioned in the second channel  219 . The fixed piston  41  is fixed to the inner surface of the first channel  217 . The flexible member  43  is fixed to the liquid inlet  213 -side of the fixed piston  41 . The filter  45  is positioned in the first channel  217  and away from the flexible member  43 . The fixed piston  51  is fixed to the inner surface of the second channel  219 . The flexible member  53  is fixed away from the liquid outlet  215 -side of the fixed piston  51 . 
     The driving assembly  30  is fixed on the outer surface of the closed chamber  10 . The drive rod  35  connects the drive piston  33  to the connecting rod  25 . The controller  60  is positioned in the closed chamber  10 . 
     Referring to  FIGS. 1 and 2 , in use, the closed chamber  10  is subjected to a predetermined degree of vacuum via the air pump, and liquid is sucked into the closed chamber  10  via the fluid channel  12 . When the liquid level in the closed chamber  10  exceeds a predetermined level, the sensor  61  generates a signal. The controller  60  transmits a start signal to the driving assembly  30 , and then the driving assembly  30  starts to work. The drive rod  35  drives the connecting rod  25  to move upwards. As a result, the action piston  23  slides in the receiving chamber  211  away from the liquid inlet  213 , and as the volume of the first chamber  2113  is increased, the air pressure in the first chamber  2113  is reduced. The air pressure difference between the first chamber  2113  and the closed chamber  10  causes the liquid in the closed chamber  10  to move through the filter  45  and the fixed piston  41 , and to be sucked into the first chamber  2113  because of the negative air pressure. This is the drainage device  100  in the first state. 
     When the action piston  23  has moved the maximum distance upward relative to the liquid inlet  213 , the first chamber  2113  is filled with liquid as shown in  FIG. 2 . Referring to  FIG. 3 , after the first chamber  2113  is filled with liquid, the drive rod  35  drives the connecting rod  25  to move downwards. As a result, the action piston  23  slides in the receiving chamber  211  towards the liquid inlet  213 , thereby reducing the volume of the first chamber  2113  and thus increasing the pressure. Under pressure, the liquid in the first chamber  2113  is forced through or around the flexible member  53  and into the second channel  219 , the flexible member  43  is pressed tightly against the fixed piston  41  by means of the applied pressure. This is the drainage device  100  in the second state, in which the liquid in the first chamber  2113  is being discharged to the outside via the second channel  219 . 
     As the drainage device  100  continuously operates between the first state and the second state, the liquid in the closed chamber  10  is drained to the outside. When the liquid level in the closed chamber  10  again falls to the predetermined level, the sensor  61  detects it and generates a closing signal. The controller  60  transmits the closing signal to the driving assembly  30 , and then the drainage device  100  stops. In addition, if there is sediment which has accumulated at the bottom of the closed chamber  10 , the sealing cover  18  can be opened to remove the sediment from the closed chamber  10 . It should be pointed out that, the connecting rod  25  and the drive rod  35  can be integrally formed. 
     When the liquid of the closed chamber  10  flows into the first chamber  2113  via the first channel  217 , the flexible member  53  seals the second channel  219 . When the liquid of the first chamber  2113  flows to the outside via the second channel  219 , the flexible member  43  seals the first channel  217 . Therefore, the outside air cannot reach the inside of the closed chamber  10  at any time. 
     While the present disclosure has been described with reference to particular embodiments, the description is illustrative of the disclosure and is not to be construed as limiting the disclosure. Therefore, various modifications can be made to the embodiments by those of ordinary skill in the art without departing from the true spirit and scope of the disclosure, as defined by the appended claims.

Technology Classification (CPC): 5