CROSS-REFERENCES TO RELATED APPLICATIONS

None.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to liquid dispensing devices. More specifically, the invention relates to a system and method for the continuous dispensing of liquid disinfectant whereby such dispensing is controlled by vacuum.

2. Description of the Related Art

There exists in the art devices for dispensing a disinfectant to disinfect fluid or liquid prior to utilization of the disinfected liquid. For example, there are devices for use in connection with septic systems that dispense chlorine into a tank for disinfecting the accumulated liquid prior to dispersion of the disinfected liquid to a sprinkler or drain field. These kinds of systems may either use solid (e.g., tablets) or liquid disinfectants. The disinfectant is further generally drawn or pulled into the liquid to be disinfected using a venturi through a phenomenon known as the venturi effect. The disinfectant used is generally chlorine.

However, there may be certain environments or regulations that do not allow certain types of disinfectants to be used or where a disinfectant other than chlorine is desired. In additional, there may be several components that comprise the disinfecting dispensing equipment which translates to multiple potential areas of failure. This would, in turn, require additional maintenance and increased costs to maintain the equipment. Having more replacement components translates to having to accommodate additional replacement parts in inventory.

Current wastewater treatment systems also impact the environment as the amount of disinfectant used often exceeds the amount needed to effectively treat wastewater. For example, current disinfecting systems using a venturi may release up to 15 drops of liquid (which is equal to 1 mL) in 1 gallon of treated wastewater. In other words, it takes 15 drops of liquid bleach to treat 1 gallon of wastewater.

Accordingly, there is a need for a stand-alone dispensing device that has a free flow gravity feed design that is environmentally friendly, low cost, easily installable on to any aerobic system and contains no moving parts. There is a further need for such device to be vacuum controlled such that the device dispenses disinfectant to a liquid continuously and in real time. There is also a further need for a dispensing device that is capable of dispensing a variety of types of disinfectants in accordance with applicable environmental, regulatory and/or consumer constraints. The present invention addresses these and other shortcomings of the currently existing disinfecting systems.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a closed system for dispensing a liquid disinfectant into a tank containing liquid (effluent) without using a venturi to dispense the disinfectant. Rather, the dispensing of the disinfectant is controlled via a vacuum. The present invention further provides for a gravity flow device that applies disinfectant to a holding tank as the water level rises, thus, giving the ultimate amount of contact time for the disinfectant to work. The disinfectant is introduced to effluent water in a holding/pump tank as the effluent enters the holding/pump tank. The longer the contact time the disinfectant has to interact with pathogens, the better the disinfectant disinfects and treats the effluent water. In short, the present invention provides for maximum contact time for minimal pathogen survival.

The inventor conducted a series of experiments demonstrating the underlying principles supporting the present invention and observed that 1″ Hg was sufficient in any size pipe to raise water within such pipe approximately 14″ in the pipe. In these experiments, the invention used six different sized pipes—also described as “sensing pipes”—having diameter sizes of 1¼″, 1″, ¾″, ½″, ⅜″ and ¼″. Each was tied together via tubing to a header having a ball valve. The water was dyed to demonstrate visually the effect the vacuum had on the water within the sensing pipe. The header was connected via tubing to a vacuum gauge which was approximately at 0.0″ Hg. This then was connected via tubing to a venturi.

When the venturi was turned on (which created a vacuum within the system), the water within each of the sensing pipes rose simultaneously and notably at the same rate with the same amount of vacuum being applied to each sensing pipe of differing diameters. After turning off the venturi, and thus ceasing the application of vacuum, the vacuum sensor measured approximately 1″ Hg of vacuum. The ball valve on the header was shut off thus, maintaining the vacuum within the sensing pipe.

What was observed was that the distance the dyed water rose in each of the sensing pipes of different diameters was about 14 inches above the surface of the water. In other words, the column of water within each of the sensing pipes was approximately 14″-15″ inches from the water surface. This length of water column within the sensing pipe and above the water surface was maintained consistently so long as the vacuum was maintained. Once the system lost vacuum, the water column began to fall down towards the surface of the water.

In an alternative embodiment, if a T was placed inline and connected to a vacuum switch (e.g., low level), the gauge was normally a closed switch with 0.38″ to 1″ Hg. As long as the system was under vacuum, the system pulled the switch open. However, a low level functioning alarm was also tied in to indicate when the level was low. When vacuum was lost, the alarm went off.

While this demonstration was prepared using a venturi to create the vacuum, the present invention operates absent a venturi.

An object of the present invention is to control the dispensing of a liquid disinfectant without a venturi.

A further object of the present invention is to provide for a disinfection device for secondary treated effluent.

A still further object of the present invention is to provide for a disinfection device that may be used with 6-10% sodium hypochlorite (household bleach) as the liquid disinfectant.

Yet another object of the present invention is to provide for a disinfection device that may be used with various kinds of disinfectants as the liquid disinfectant.

A further object of the present invention is to provide the maximum amount of contact time between the liquid disinfectant and the liquid to be treated.

To contrast the prior art to the present invention, reference is now made toFIG. 1which depicts graphical representation10illustrating the relationship between the amount of liquid in the tank and the level of residual chlorine as a function of time for front side dosing using a venturi front of pump cycle. Front side dosing means all dose is provided as the pump starts. Left axis12represents the quantity of liquid (gal.). Right axis14represents the current level of residual chlorine (mg/L). Bottom axis16represents time (24 hours). Metered flow is a slow steady addition of chlorine drops when the pump starts and continues to run. However, once the initial dosage is provided, minimal, if any, disinfecting occurs until the pump cycle resumes. In contrast, the present invention, without the use of a venturi, controls the dosage of disinfectant into the tank of effluent to be treated to disinfect continuously and in real time.

Utilizing gravity and vacuum controlled dispensing of disinfectant rather than a venturi to control the dispensing or dosing of the disinfectant, the present invention thus dispenses disinfectant continuously in real time. This may be demonstrated quantitatively. Referring now toFIG. 2, graphical representation18illustrates the relationship between the amount of liquid in the tank and the level of residual chlorine as a function of time. Left axis20represents the quantity of liquid (gal.). Right axis22represents the current level of residual chlorine (mg/L). Bottom axis24represents time (24 hours).

As shown inFIG. 2, an almost linear and proportional relationship between the amount of chlorine and water exists as a function of time. At the start of the pump cycle (12 am) the quantity of water in the pump tank is 0.0 gal. and the residual chlorine is near 2.0. Then at 3:00 am, there is an increase of water to about 10 gal. At that time the residual chlorine is at about 1.5. At 6 am, the water level increases to about 50 gal. and the residual chlorine is about 1.0. The residual chlorine level decreases until about 7 am then begins to increase in concentration. At about 9 am the residual chlorine level is about 0.75 whereas the water level has increased to about 100 gal. This proportional increase of both the water level and residual chlorine concentration level continues until about 12 am where the water quickly decreases from about 250 gal. to about 50 gal. while the residual chlorine plateaus at about 2.0. This would then coincide to the residual chlorine level described at the beginning of the pump cycle. The water level also continues to decrease after the pump cycle back down to 0.0 gal. before the next pump cycle begins. As the water level in the tank increases (from between 6 am to 12 am), there appears to be a somewhat linear relationship with the chlorine level which also increases proportionately during this same time period.

Stated differently, at the start of a pump cycle, the water level in the pump/holding tank is high enough, as all of the daily water usage is satisfied by a level float, probably until midday. However, the water held in the tank is monitored by a timer and is not generally satisfied by midnight (timer setting). When both the float level and the timer settings coincide, the pump cycle begins.

Some jurisdictions, e.g., Texas, require spray discharge/pump cycle to occur between 12 am-5 am. It is important to note that there is always about 100-150 gallons or more in the tank all the time at “0” (SeeFIG. 2) because the pump intake is about 12″ off the bottom of the tank. There is always about 16-18″ of water in a tank because of the location of the pump intake. The graph starts at 0 which corresponds to daily water usage. Water level/usage decreases overnight due to inactivity, e.g., everyone is sleeping. In the morning the water level and water usage increases, then becomes stagnant and maybe increases during the lunch hour and continues to increase when everyone is at home in the evening using water before bedtime.

When stagnant water flows, chlorine residuals decline due to the nature of agressive/nonstable sodium hypochlorite (bleach). When flows are present, chlorine residuals are proportionally linear. SeeFIG. 2.

Over the course of several experiments, the inventor discovered that an increase in the inner diameter of the sensing tube translated into an observed increase in the resulting chlorine concentration in the pump tank with no losses of chlorine. For example, with a 500 gal pump tank, using a concentration of sodium hypochlorite of 6.25%, a sensing tube of 0.5 inches in diameter and having the following parameters:

Pump Tank Wet Well Height55inchesPump Tank Total Volume771gallonsUnit Volume14.02gal/inchSensing Tube Diameter0.5inchesSodium Hypochlorite Concentrations6.25%

The following resulted:

TABLE 1Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.531.611.610.00042455.72.1

When the sensing tube diameter was increased to 0.75 inches, and maintaining the remaining parameters, the results were as follows:

TABLE 2Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.533.623.620.001054125.24.7

Increasing the sensing tube diameter to 1.00 (all other parameters unchanged), gave the following:

TABLE 3Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.536.436.430.001796222.68.4

The inventor performed a similar experiment increasing the sodium hypochlorite concentration to 8.00% but all other parameters remaining unchanged:

Pump Tank Wet Well Height55inchesPump Tank Total Volume771gallonsUnit Volume14.02gal/inchSensing Tube Diameter0.5inchesSodium Hypochlorite Concentrations8.00%

The following resulted:

TABLE 4Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.531.611.610.00042471.22.7

When the sensing tube diameter was increased to 0.75 inches, and maintaining the remaining parameters, the results were as follows:

TABLE 5Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedw/no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.533.623.620.001054160.36.0

Increasing the sensing tube diameter to 1.00 (all other parameters unchanged), gave the following:

TABLE 6Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedw/no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.536.436.430.001796285.010.7

The inventor performed a similar experiment increasing the sodium hypochlorite concentration to 10% but all other parameters remaining unchanged:

Pump Tank Wet Well Height55inchesPump Tank Total Volume771gallonsUnit Volume14.02gal/inchSensing Tube Diameter0.5inchesSodium Hypochlorite Concentrations10%

The following resulted:

TABLE 7Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedw/no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.531.611.610.00042489.13.4

When the sensing tube diameter was increased to 0.75 inches, and maintaining the remaining parameters, the results were as follows:

TABLE 8Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.533.623.620.001054200.47.6

Increasing the sensing tube diameter to 1.00 (all other parameters unchanged), gave the following:

TABLE 9Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.536.436.430.001796356.213.4

Increasing the pump tank size produced similar results. For example, with a 1000 gal pump tank, using a sensing tube of 0.5 inches in diameter, and having the following parameters:

Pump Tank Wet Well Height56inchesPump Tank Total Volume1220gallonsUnit Volume21.79gal/inchSensing Tube Diameter0.5inchesSodium Hypochlorite Concentrations6.25%

The following resulted:

TABLE 10Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.541.231.611.610.00042455.71.4

When the sensing tube diameter was increased to 0.75 inches, and maintaining the remaining parameters, the results were as follows:

TABLE 11Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.541.233.623.620.001054125.23.0

Increasing the sensing tube diameter to 1.00 (all other parameters unchanged), gave the following:

TABLE 12Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.541.236.436.430.001796222.65.4

Increasing the pump tank size produced similar results. For example, with a 1000 gal pump tank, using a sensing tube of 0.5 inches in diameter, and having the following parameters:

Pump Tank Wet Well Height56inchesPump Tank Total Volume1220gallonsUnit Volume21.79gal/inchSensing Tube Diameter0.5inchesSodium Hypochlorite Concentrations6.25%

The following resulted:

TABLE 13Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.541.231.611.610.00042455.71.4

When the sensing tube diameter was increased to 0.75 inches, and maintaining the remaining parameters, the results were as follows:

TABLE 14Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.533.623.620.001054125.24.7

Increasing the sensing tube diameter to 1.00 (all other parameters unchanged), gave the following:

TABLE 15Resulting ChlorineChange inSensing TubeEquivalentEquivalentMassConcentrationPump TankEquivalentVolumeVolumeVolumeEquivalentChlorinein Pump TankHeightVolumeChangeBleachBleachVolumeDosedwith no losses(in.)(L)(mL)(mL)(gal.)(drops)(mg)(mg/L)0.526.536.436.430.001796222.68.4

As demonstrated above, these calculations demonstrate that varying the diameter of the different sensing tubes directly affects the chlorine dose.

The dispensing system of the present invention adjusts the amount of chlorine that drips into the pump tank by controlling the amount of air allowed into the disinfectant dispensing reservoir via the sensing pipe. A different size will give a different result. The flexible tubing from the top of the sensing pipe connects directly into the liquid dispensing reservoir, preferably at the highest point as it is a “vent,” but only in the sense that the reservoir only receives air from the sensing pipe, not atmosphere, as the present invention is a closed system.

As the water column rises, this allows air to enter into the reservoir and by entering into the reservoir, the vacuum within the plastic tubing is lessened which allows the dispensing tube to dispense fluid, e.g., disinfectant, such as chlorine.

The present invention demonstrates that 1″ Hg lifts approximately 14″ of water column. The column of air above the water column controls the feed rate (chlorine dosage) of the liquid dispensing reservoir. Reducing the diameter of column of air (by reducing the inner diameter of the sensing pipe) reduces the amount of air fed into the air locked liquid dispensing reservoir.

The present invention substantially reduced the amount of disinfectant required to treat wastewater over current disinfecting systems. The present invention reduces the amount of liquid chlorine used by about half. With the present invention, it now only takes 7 drops of bleach per gallon to effectively treat wastewater. This is tantamount to about 16,000 gallons of water treated with about 2 gallons of disinfectant, e.g., bleach. This is quite an unexpected result. The inventor is not aware of any other device or system that can effectively treat this much wastewater with such a minimal amount of liquid chlorine. The benefits of reducing the amount of disinfectant to effectively treat wastewater include a more environmentally friendly treatment system and a reduction on cost for consumables and operating costs.

An advantage of the present invention is the free flow gravity feed design that is easily installable on to any aerobic system and contains no moving parts. An additional advantage is that the present invention is vacuum controlled such that the device dispenses disinfectant to a liquid continuously and in real time. Still another advantage is that the present invention is capable of dispensing a variety of types of disinfectants in accordance with applicable environmental, regulatory and/or consumer constraints while reducing the number of components and consumables which translates into substantial cost savings.

