Abstract:
This invention relates to an automated vacuum liquid waste handling system having two or more waste vessels, with a liquid-level sensor, a means for filling the waste vessels with waste, a means for switching from the first waste vessel, once full, to one or more other waste vessels that are not full, and a means for simultaneously removing said waste from the first full waste vessel to output holding stations and filling another waste vessel so that waste collection is not interrupted.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The collection of depleted and contaminated chemicals from chemical processing equipment is an important facet of all manufacturing processes that utilize such chemicals. Where hazardous waste chemicals are not properly controlled the manufacturing facilities that utilize the chemicals can be shut down, resulting in significant and expensive losses of material and equipment. Also, high-levels of volatile organic compounds (VOCs) can be generated by waste chemicals, and the control of such VOCs is a significant problem. Therefore, a need exists for reliable, automated waste chemical collection systems, and particularly systems such as those liquid waste collection systems disclosed in U.S. Pat. Nos. 5,148,945 and 6,148,846. However, there is a need for improvement of these systems.  
         [0002]     As an example, high throughput screening instruments generate a large volume of liquid waste. With existing high throughput screening instruments, the large volumes of liquid waste generated must be constantly monitored and collected into waste bottles for disposal. Some disadvantages with high throughput screening liquid waste disposal are that it is currently a manual process and it can require waste disposal when robotics operators are not on-site.  
         [0003]     Thus, a need still exists for a liquid waste management system with no human contact with waste and the waste bottles are emptied automatically at any time of the day, without requiring the presence of a robotics operator.  
       SUMMARY OF THE INVENTION  
       [0004]     This invention relates to an automated vacuum liquid waste handling system having two or more waste vessels, with a liquid-level sensor, a means for filling the waste vessels with waste, a means for switching from the first waste vessel, once full, to one or more other waste vessels that are not full, and a means for simultaneously removing said waste from the first full waste vessel to output holding stations and filling another waste vessel so that waste collection is not interrupted. The automated vacuum liquid waste handling system can to switch back and forth, as needed, to one or more of the waste vessels as each becomes either full or is emptied.  
         [0005]     This invention also relates to an automatic process for handling liquid waste that minimizes human contact with waste and allows full waste vessels to be emptied automatically at any time of the day, without requiring an operator to be present. The automated vacuum liquid waste handling system comprises using a vacuum and pressure system. The vacuum system draws the liquid waste from the liquid waste production source into the waste vessel. As the fluid accumulates in the vessel the liquid level rises engaging liquid-level sensor when the vessel is full. An electronic system controller is connected to the liquid-level sensor in the waste vessel as well as to the 2-way and 3-way control valves which control the flow of liquid waste throughout the system. The 2-way and 3-way control valves are controlled by the electronic system controller that alters the flow of liquid waste between a plurality of waste vessels. When a high liquid level alarm signal is received from the liquid-level sensor the electronic system controller engages the appropriate control valves so that the flow of liquid waste is stopped at the full vessel and the liquid waste in the full vessel is emptied at the holding station using a removal pump. The flow of the liquid waste is then activated and sent to an unfilled vessel thereby filling the unfilled vessel. After the full vessel is emptied the liquid-level sensor signals the electronic system controller to engage the appropriate control valves to isolate the emptied vessel from the removal pump. This and other aspects of the invention are realized upon a review of the specification as a whole. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a diagram of the automated vacuum liquid waste handling system utilizing two waste vessels. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0007]     The present invention relates to an automated vacuum liquid waste handling system that minimizes human contact and allows full waste vessels to be emptied automatically at any time of the day, without requiring an operator to be present.  
         [0008]     As shown in  FIG. 1  (illustrating a system with 2 waste vessels), the automated vacuum waste handling system ( 50 ) comprises liquid waste production source ( 19 ), liquid waste supply lines ( 9 ) and ( 10 ) each having at least one 2-way control valve ( 12 ) and ( 13 ), liquid waste vessels ( 1 ) and ( 11 ) each having liquid-level sensors ( 22 ) and ( 33 ), respectively, and three openings ( 5 ), ( 6 ) and ( 7 ) and ( 5   a ), ( 6   a ) and ( 7   a ), respectively, liquid waste output lines ( 10   a ) and ( 9   a ) each having at least one 2-way control valve ( 12   a ) and ( 13   a ), removal pump ( 40 ), vacuum source lines ( 10   b ) and ( 9   b ), each vacuum source line having a 3-way control valve (14) and (15) attached thereto, vacuum pump ( 20 ) and T-joints ( 2 ), ( 3 ) and ( 4 ).  
         [0009]     The liquid waste production source ( 19 ) is connected to liquid waste supply lines ( 9 ) and ( 10 ) by a T-joint ( 2 ). The 2-way control valve ( 13 ) and ( 12 ) on each liquid waste supply line ( 9 ) and ( 10 ) is located after T-joint ( 2 ) and before waste vessels ( 1 ) and ( 11 ), respectively.  
         [0010]     Liquid waste vessel ( 1 ) and ( 11 ) each have three openings, ( 5 ), ( 6 ) and ( 7 ) and ( 5   a ), ( 6   a ) and ( 7   a ), respectively. Liquid waste supply line ( 10 ) is attached to liquid waste vessel ( 1 ) through opening ( 5 ). Liquid waste output line ( 10   a ) is connected to liquid waste vessel ( 1 ) through opening ( 7 ). Vacuum source line ( 10   b ) is connected to liquid waste vessel ( 1 ) through opening ( 6 ). Liquid waste output line ( 10   a ) containing at least one 2-way control valve ( 12   a ) attached thereto and is connected to a removal pump ( 40 ) by T-joint ( 3 ). Vacuum source line ( 10   b ) having at least one 3-way control valve ( 14 ) attached thereto and is connected to vacuum pump ( 20 ) by T-joint ( 4 ).  
         [0011]     Liquid waste supply line ( 9 ) is attached to liquid waste vessel ( 11 ) through opening ( 5   a ). Liquid waste output line ( 9   a ) is connected to liquid waste vessel ( 11 ) through opening ( 7   a ). Vacuum source line ( 9   b ) is connected to liquid waste vessel ( 11 ) through opening ( 6   a ). Liquid waste output line ( 9   a ) containing at least one 2-way control valve ( 13   a ) attached thereto and is connected to removal pump ( 40 ) by T-joint ( 3 ). Vacuum source line ( 9   b ) having at least one 3-way control valve ( 15 ) attached thereto and is connected to vacuum pump ( 20 ) by T-joint ( 4 ).  
         [0012]     Removal pump ( 40 ) is connected to dump line ( 30 ), which is connected to an output holding station ( 31 ). The liquid-level sensors ( 22 ) and ( 33 ), 2-way control valves ( 12 ), ( 13 ), ( 12   a ), ( 13   a ) and 3-way control valves ( 14 ) and ( 15 ) are connected to an electronic system controller ( 60 ) that controls the flow of liquid waste throughout the waste handling system. The electronic system controller ( 60 ) engages the appropriate control valves so that liquid waste vessel ( 1 ) or ( 11 ) is emptied when full or filled when empty, which ever is appropriate.  
         [0013]     In operation, the automated vacuum liquid waste handling system ( 50 ) pumps liquid waste through liquid waste supply lines depending upon which line is open. When one liquid waste supply line is open the other(s) is closed.  
         [0014]     Using  FIG. 1  as a model, when liquid waste supply line ( 10 ) is opened, generally this means 2-way control valve ( 12 ) is open, 3-way control valve ( 14 ) is open to vacuum pump ( 20 ) and 2-way control valve ( 12   a ) is closed to removal pump ( 40 ). Liquid waste is then pumped, using vacuum pump ( 20 ) from liquid waste production source ( 19 ) through liquid waste supply line ( 10 ) to liquid waste vessel ( 1 ). Liquid waste is collected in liquid waste vessel ( 1 ) until it becomes full at which time the liquid-level sensor( 22 ) is activated. This signals the electronic control system ( 60 ) to close 2-way control valve ( 12 ); switch 3-way control valve ( 14 ) to release the vacuum on liquid vessel ( 1 ); open 2-way control valve ( 13 ) to accept liquid waste and send it to liquid vessel ( 11 ); switch 3-way control valve ( 15 ) to vacuum pump ( 20 ) to provide vacuum to liquid waste vessel ( 11 ); open 2-way control valve ( 12   a ); and activate removal pump ( 40 ) to draw waste from liquid waste vessel ( 1 ). Once liquid waste vessel ( 1 ) is empty liquid-level sensor( 22 ) is activated signaling the electronic controll system ( 60 ) to close 2-way control valve ( 12   a ) and shut off removal pump ( 40 ).  
         [0015]     Once liquid waste vessel ( 11 ) becomes full the liquid-level sensor means ( 33 ) is activated, which signals the electronic control system ( 60 ) to close 2-way control valve ( 13 ), switch 3-way control valve to release the vacuum on liquid vessel ( 11 ); open 2-way control valve ( 12 ) to accept waste to liquid waste vessel ( 1 ); open 3-way control valve ( 14 ) to vacuum pump ( 20 ) allowing vacuum to liquid vessel ( 1 ); open 2-way control valve ( 13   a ) and activate removal pump ( 40 ) to draw waste from liquid waste vessel ( 11 ). Once liquid waste vessel ( 11 ) is empty liquid-level sensor ( 33 ) is activated thereby signalling 2-way control valve ( 13   a ) to close and shutting off removal pump ( 40 ).  
         [0016]     The automated vacuum liquid waste handling system of the claimed invention is comprised of at least two liquid waste vessels. When there are three or more liquid waste vessels the system can be set up to fill and/or empty the vessels in succession or some other pre-determined order. Alternatively, the liquid waste handling system can be set up to operate by modules. For example, it can have two modules, module A, having liquid waste vessels  1  and  2  and module B, having liquid waste vessels  3  and  4 . In this example liquid waste vessel  1  can collect liquid waste until it is filled at which point it stops collecting and liquid waste vessel  2  begins to collect waste until it is filled. Once liquid waste vessel  2  is filled Module A can be trigger to begin emptying the vessels and liquid vessel  3  of module B can begin collecting liquid waste until it is filled at which point liquid waste vessel  4  begins collecting liquid waste. Each module can be controlled by a separate electronic system controller, or a single electronic system controller can be used. As one skilled in the art can imagine, there are many ways that the liquid waste can be collected with a multi-waste vessel system.  
         [0017]     Liquid-level sensor means that can be used in this invention are those known in the art. Examples are those that have a 2-point float switch, ultrasonic sensor, magnetostrictive sensor or any other continuous liquid level measurement sensors. Generally, the 2-point sensor has a float switch that rises as the waste vessel is filled with liquid waste, such that when the float switch reaches the top of the vessel, the sensor is activated. Additionally, when the waste vessel is emptied, the float switch falls, such that when the float switch is at the bottom of the vessel the sensor is activated and signals that the waste vessel is empty. An example of a 2-point sensor is GEMS LS-700. The liquid-level-capacity sensor serves to detect when the liquid level in the vessel is empty or full. Thus, the sensor has a dual function. When a waste vessel is empty, the sensor in this vessel signals the electronic system controller to open the control valves responsible for filling the vessel. When a waste vessel is full the sensor in this vessel signals the electronic system controller to close the control valves responsible for filling the vessel and open the control valves responsible for emptying the vessel.  
         [0018]     Electronic system controller that can be used in this invention are known in the art and are analog, digital, or a combination. When the liquid-level-capacity sensor is activated the electronic system controller ( 60 ) engages the appropriate control valves so that the flow of liquid waste throughout the system is controlled.  
         [0019]     Examples of known two-way and three-way control valves that can be used in this invention are solenoid, ball valve, elliptical valve, diaphragm valve, needle valve and the like. The control valve should be one that is resistant to caustic fluids, if caustic fluids are being used. The ASCO Valve is an example of a two-way control valve.