Abstract:
The subject matter disclosed herein relates to vehicle-based mobile fluid delivery apparatus and methods for dispensing fluid from a vehicle-based tank.

Description:
RELATED APPLICATION 
       [0001]    This is a PCT application claiming priority to U.S. Provisional application No. 60/894,605, filed on Mar. 13, 2007, which is in its entirety incorporated herewith by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is related to vehicle-based mobile fluid delivery systems, and more particularly, to apparatus and methods for dispensing fluid from a vehicle-based tank. 
       BACKGROUND 
       [0003]    Vehicle-based mobile fluid delivery systems are used in a number of applications, such as, but not limited to, the dispensing of fluid-based lawn chemicals. Vehicles used for the delivery and dispensing of fluid-based lawn chemicals commonly have a fluid storage tank that dispenses the fluid contents through a hose via a pump. The pump creates the fluid pressure required to dispense the fluid and to create the desired spray pattern and range from the nozzle coupled to the dispensing end of the hose, such that the service personnel can spray the fluid on a lawn, for example. 
         [0004]    A common size of the fluid storage tank adapted for lawn service is 400 gallons. The pump drives the fluid in the storage tank through a hose. A common quantity of fluid dispensed at each service call is approximately 5 to 10 gallons for a small residential lawn. 
         [0005]    The pump is commonly powered via a power take-off (PTO) driven by the engine of the vehicle, commonly off of a drive gear in the transmission; the output shaft of the PTO engaging the pump via a clutch pack. In standard operation, the pump is engaged with the PTO and the engine is driven at a high idle speed sufficient to drive the pump. The pump is left engaged with the PTO, and thus the engine is operated at high idle, for the duration of the service call, so as to maintain the fluid pressure in the hose. 
         [0006]    Continuous operation of the vehicle engine at high idle is associated with loud engine noise, air pollution, high consumption of fuel, increased wear on the vehicle engine/transmission, pump, and the PTO, among other things. Continuous operation of the pump, and therefore operating the vehicle engine at high idle, is mainly due to convenience of operation. It is not uncommon for the hose to be extended hundreds of feet, for example 400 feet or more, from where the pump controls are located. Further, it is not uncommon for the operator to wear protective gear, including bulky water-proof gloves and body coverings, making the operation of control switches difficult and inconvenient. Therefore, it is common practice for the operator to leave the pump engaged with the PTO with the vehicle engine running at high idle throughout the service call which can be for ten&#39;s of minutes. 
         [0007]    The pump commonly used is a diaphragm pump. A diaphragm pump is a positive displacement pump that uses a combination of the reciprocating action of a flexible diaphragm and check valves. The diaphragm is flexed causing the volume of the pump chamber to increase, decreasing the pressure and drawing the fluid into the chamber. When the diaphragm is flexed causing the volume of the pump chamber to decrease, the chamber pressure increases forcing the fluid currently drawn in out. 
         [0008]    A significant problem with current fluid delivery vehicles relates to problems associated with the conveyed fluid. The chemical composition of the fluid-based lawn chemicals, for example, can be highly corrosive, such as associated with iron-based moss killer and fertilizer. Positive displacement pumps are particularly susceptible to damage caused by the corrosive fluid dispensed and left therein. Such corrosion damage to a pump can cause downtime for the fluid vehicle and necessitate the repair or replacement of the damaged pump at considerable expense, particularly since these types of pumps can be relatively expensive and/or time consuming to repair or replace. Moreover, if delays are encountered in obtaining a replacement pump or parts therefore, the downtime for the fluid vehicle can substantially increase substantially impairing economic value. 
         [0009]    Current fluid-delivery vehicles with pumps driven by PTO&#39;s thus tend to be relatively complex and require time-consuming purging and cleaning procedures. 
         [0010]    A PTO drive system can add considerably to both the initial cost and the ongoing maintenance expenses associated with a fluid-delivery vehicle. Such current vehicles and their fluid distribution systems also tend to have a number of moving parts, which are susceptible to damage and wear from corrosion. 
         [0011]    It is therefore desired to provide a fluid delivery system wherein the fluid is delivered as needed with relatively few moving parts and with less corrosion concerns. Moreover, it is desired to provide a fluid delivery system which is not dependent on the engine idle speed yet provides reliable pressurization for attaining operating pressures of up to 300 PSI or more, and to provide such a system which can accommodate various fluid-delivery application procedures. 
         [0012]    What is needed in the art is a vehicle-based mobile fluid delivery system with a pressurized discharge system that overcomes the limitation of current systems and that provides dispensing of the fluid product without the associated high idle operation of the vehicle and without the associated maintenance issues of the pump. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Like reference numbers generally indicate corresponding elements in the figures. 
           [0014]      FIG. 1  illustrates a vehicle-based mobile fluid delivery system in accordance with an embodiment; and 
           [0015]      FIG. 2  is a schematic of a fluid-delivery system in accordance with an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Reference will now be made to embodiments illustrated in the drawings and specific language which will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated devices, as such further applications of the principles of the invention as illustrated therein as being contemplated as would normally occur to one skilled in the art to which the invention relates. 
         [0017]    Embodiments in accordance with the present invention provide a vehicle-based mobile fluid-delivery system. The fluid-delivery is provided by apparatus comprising a secondary storage tank pressurized by gas pressure. The gas pressure is provided by any suitable means, including means associated with a compressor, compressed gas cylinder, and the like. 
         [0018]      FIG. 1  illustrates a vehicle-based mobile fluid delivery system  2  comprising a primary storage tank  20 , a secondary storage tank  30 , a gas pressure supply  40  adapted to pressurize the secondary storage tank  30 , and a discharge outlet  50 , in accordance with an embodiment of the present invention. The vehicle-based mobile fluid delivery system  2  may be adapted to be coupled to a vehicle  10 . The vehicle  10  may include a cab  12  and a chassis  14 , the chassis  14  being adapted for mounting the fluid handling components. 
         [0019]    The primary storage tank  20  is a fluid containment vessel including a primary inlet  22  adapted for filling the primary storage tank  20  with a fluid, and a primary outlet  24  adapted for dispensing fluid therefrom. The primary storage tank  20  may be fabricated from any material adapted for containment of a desired fluid, such as, but not limited to, metal, polymer and fiberglass material. The primary storage tank  20  has a predetermined fluid capacity, such as, but not limited, to that associated with a day&#39;s worth of fluid delivery. 
         [0020]    The secondary storage tank  30  is a containment vessel having a secondary inlet  32 , a secondary outlet  34 , a pressure inlet  36 , and a pressure outlet  38 . The secondary inlet  32  is adapted for coupling in fluid engagement with the primary outlet  24  of the primary storage tank  20 . The secondary outlet  34  is adapted for dispensing the fluid from the secondary storage tank  30 . Control of fluid from the primary storage tank  20  to the secondary storage tank  30  may be provided by a first valve  21  in fluid engagement with the primary outlet  24  and secondary inlet  32 . Control of fluid from the secondary storage tank  30  to the secondary outlet  34  may be provided by a second valve  31  in fluid engagement with the secondary outlet  34 . The pressure inlet  36  is coupled in fluid engagement with the pressure supply  40 . The pressure supply  40  is adapted for providing gas pressure to the secondary storage tank  30 . The pressure outlet  38  may be provided with a pressure release valve  39  in fluid engagement therewith for overpressure protection and pressure relief. The secondary storage tank  30  may be fabricated from any material adapted for containment of a desired fluid under pressure, such as, but not limited to, metal, polymer and fiberglass material. 
         [0021]    The secondary storage tank  30  may have any fluid capacity. The secondary storage tank  30  may have a predetermined fluid capacity such as, but not limited to, that associated with a single application of fluid delivery at a job site. In accordance with an embodiment of the present invention, the secondary storage tank  30  may have a capacity of 5 to 10 gallons so as to provide fluid for a single application. In accordance with another embodiment of the present invention, the secondary storage tank  30  may have a capacity of 30 to 50 gallons so as to provide fluid for a large single application or provide for multiple applications without the need to release the gas pressure and fill and pressurize the secondary storage tank  30  as often as compared with a smaller capacity. 
         [0022]    Gas pressure may be provided to the pressure inlet  36  of the secondary storage tank  30  with apparatus associated with a gas pressure supply  40 . Apparatus associated with gas pressure supply  40  includes, but is not limited to, a compressor and compressed gas cylinders. Air compressors include, but not limited to, electric, gas and hydraulic-driven compressors. A compressor may be driven off of an electric, gas and/or hydraulic system of the vehicle  10 , or an independent system such as, but not limited to, storage batteries. In accordance with an embodiment of the present invention, the gas pressure supply  40  may be an air compressor driven by an electrical system of the vehicle  10 , such as, but not limited to a 12 or 24 volt electrical system. In accordance with another embodiment of the present invention, the gas pressure supply  40  may be an electric air compressor powered by storage batteries that are charged by an electrical system of the vehicle  10 . In accordance with another embodiment of the present invention, the gas pressure supply  40  may be an electric air compressor powered by storage batteries. 
         [0023]    In an embodiment in accordance with the present invention, the pressure supply  40  further comprises a pressure switch  42  adapted for sensing pressure in the secondary storage tank  30 . When the pressure switch  42  detects that the pressure is below a predetermined value, the pressure supply  40  is caused to engage and increase the pressure in the secondary storage tank  30 . When the pressure switch  42  detects that the pressure is above a predetermined value, the pressure supply  40  is disengaged. 
         [0024]    In accordance with an embodiment wherein the pressure supply  40  is an air compressor, engagement and disengagement with the secondary storage tank  30  is affected by use of a controller turning the compressor on/off. In accordance with an embodiment wherein the pressure supply  40  is a compressed gas cylinder, engagement and disengagement with the secondary storage tank  30  is affected by use of a valve opening/closing gas communication between the secondary storage tank  30  and the cylinder. 
         [0025]      FIG. 2  is a schematic of a fluid-delivery system  4  in accordance with an embodiment of the present invention. The fluid-delivery system  4  comprises a secondary storage tank  30  and a pressure supply  40  in fluid engagement therewith adapted to pressurize the secondary storage tank  30 . The secondary storage tank  30  comprises a secondary inlet  32  with fluid communication controlled by a first valve  21 , a secondary outlet  34  with fluid communication controlled by a second valve  31 , a pressure inlet  36  adapted to couple in fluid engagement with the pressure supply  40 , and a pressure outlet  38  with fluid communication controlled by a pressure valve  39 . 
         [0026]    Referring again to  FIGS. 1 and 2 , in accordance with an embodiment of a process of the present invention, the pressure valve  39  is opened to bring the secondary storage tank  30  to atmospheric pressure. The first valve  21  is opened and fluid from the primary storage tank  20  is supplied to the secondary storage tank  30  by, such as, but not limited to, gravity feed. The secondary storage tank  30  is filled with a predetermined quantity of fluid. The first valve  21  is closed and the pressure valve  39  is closed and set in an overpressure protection operation. The pressure supply  40  is caused to engage and pressurize the secondary storage tank  30  to a predetermined pressure above atmosphere, such as, but not limited to 125 psi. The second valve  31  is opened so as to dispense the fluid, such as, but not limited to, through a hose  52  coupled to and in fluid communication with an outlet of the second valve  31 , the gas pressure maintained to a predetermined pressure within the secondary storage tank  30  so as to dispense the fluid. 
         [0027]    In accordance with an embodiment of the present invention, the fluid-delivery system  4  further comprises a pressure switch  42 . The pressure switch  42  is located so as to sense the pressure within the secondary storage tank  30 . The pressure switch  42  is in sensing communication with the pressure supply  40 . The engagement and disengagement of the pressure supply  40  may be controlled by a signal from the pressure switch  42 . In an automatic operation in accordance with an embodiment, the pressure switch  42  controls the operation of the pressure supply  40  by engaging and disengaging the pressure supply  40  in accordance with the pressure switch  42  sensing a predetermined pressure range, such as, but not limited to, 125-150 psi, and thus, controlling the pressure within the secondary storage tank  30  within the predetermined pressure range. The operation of the pressure supply  40  is thus controlled so as to provide a pressure within the secondary storage tank  30  within a predetermined range without intervention by the operator. The pressure supply  40  is controlled on an as-needed basis rather than on a continual basis. 
         [0028]    Referring again to  FIG. 1 , in accordance with an embodiment, the primary outlet  24  may be adjacent to and/or a part of a primary storage tank bottom  27  of the primary storage tank  20 , and likewise, secondary inlet  32 , may be adjacent to and/or a part of a secondary storage tank bottom  37  of the secondary storage tank  30 . The relative position of the primary outlet  24  being adjacent the primary storage tank bottom  27  and the secondary inlet  32  being adjacent the secondary storage tank bottom  37  facilitates the process of fluid transport and mixing described below. 
         [0029]    Referring to  FIGS. 1 and 2 , in accordance with an embodiment of a process for filling the secondary storage tank  30  with fluid from the primary storage tank  20 , the pressure valve  39  is opened to bring the secondary storage tank  30  to atmospheric pressure. The first valve  21  is opened and fluid from the primary storage tank  20  is supplied to the secondary storage tank  30 . The secondary storage tank  30  is filled with a predetermined quantity of fluid. The movement of fluid from the primary outlet  24  to the secondary inlet  32  and into the secondary storage tank  30  creates fluid turbulence at the secondary storage tank bottom  37  which is particularly helpful in stirring up and mixing any sedimentary products in the fluid. For example, certain lawn care products, such as those containing ferrous sulfate for killing moss in lawns, will settle out within the secondary storage tank  30  without suitable agitation. The movement of fluid from the secondary inlet  32  into the secondary storage tank  30  helps to suspend or mix product that might otherwise settle. 
         [0030]    In accordance with an embodiment of a process for dispensing fluid from the secondary storage tank  30  through a hose  52 , the first valve  21  is closed and the pressure valve  39  is closed and set as an overpressure protection operation. The pressure supply  40  is caused to engage and pressurize the secondary storage tank  30  to a predetermined pressure above atmosphere. The second valve  31  is opened so as to dispense the fluid, such as, but not limited to, through the hose  52  coupled to the outlet of the second valve  31 , the gas pressure maintained to a predetermined pressure within the secondary storage tank  30  so as to dispense the fluid under pressure. 
         [0031]    In accordance with an embodiment of a process for back-flushing fluid from the secondary storage tank  30  back into the primary storage tank  20 , the second valve  31  is closed and the pressure within the secondary storage tank  30  is raised to a higher pressure head than that at the primary outlet  24 . The primary storage tank  20  may remain open to the atmosphere so as to maintain atmospheric pressure within the primary storage tank  20 . The first valve  21  is opened and fluid from the secondary storage tank  30  is supplied to the primary storage tank  20  as the pressure in the secondary storage tank  30  reduces to that of the primary storage tank  20 . 
         [0032]    In accordance with another embodiment of a process for back-flushing fluid from the secondary storage tank  30  back into the primary storage tank  20 , the second valve  31  is closed and the pressure within the secondary storage tank  30  is raised to a higher pressure head than that at the primary outlet  24 . The primary storage tank  20  may remain open to the atmosphere so as to maintain atmospheric pressure within the primary storage tank  20 . The first valve  21  is opened and fluid from the secondary storage tank  30  is supplied to the primary storage tank  20  as the pressure in the secondary storage tank  30  is controlled to maintain a higher pressure that that at the primary outlet  24  such that substantially all of the fluid is removed from the secondary storage tank  30 . The secondary storage tank  30  may be substantially emptied into the primary storage tank  20  where the secondary inlet  32  is in close proximity to the secondary storage tank bottom  37 . 
         [0033]    The movement of fluid from the secondary storage tank  30  to the primary storage tank  20  remixes the fluid and creates fluid turbulence in the primary storage tank bottom  27  which is particularly helpful in stirring up and mixing any sedimentary products in the fluid. 
         [0034]    In accordance with an embodiment of a process, the secondary storage tank  30  may be substantially emptied into the primary storage tank  20  after a service call and the secondary storage tank  30  refilled with fluid from the primary storage tank  20  before the next service call. In this way, the fluid dispensed from discharge outlet  50  is relatively well mixed from the fluid mixing during the back-flushing and filling process of the secondary storage tank  30 . 
         [0035]    It is appreciated that complete emptying of the secondary storage tank  30  is not necessary to create fluid mixing. Fluid mixing will occur with the addition of fluid from the primary storage tank  20  into the secondary storage tank  30 . 
         [0036]    Embodiments in accordance with the present invention provide a vehicle-based mobile fluid delivery system that addresses the limitations of current systems. The power take-off (PTO) subsystem may be eliminated such that the operation of the pressurization system is not dependent on the operation of the vehicle engine. Therefore the engine of the vehicle need not be running for the operation of the fluid delivery system, thus saving in fuel costs, reducing noise and air pollution, and reducing engine wear and tear. The fluid pump has been eliminated in favor of a gas pressure delivery system eliminating the cleaning, maintenance and replacement issues associated with current fluid delivery systems. With the elimination of the pump and associated PTO elements, the components and complexity of the system is greatly reduced resulting in reduced equipment costs. Since a pump is not used in the fluid stream, fluids not adapted for pumping, or particularly damaging or corrosive to a pump, can be used with this system. 
         [0037]    It is understood that the embodiments described are adapted for fluid delivery systems of many types, such as, but not limited to, the dispensing of lawn care chemicals, the dispensing of seed/mulch slurries used for reseeding bare ground, and spray-down/cleaning of equipment, among many others. 
         [0038]    While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention and the limits of the appended claims.