Plural component mixing system

A plural component mixing system includes an automatic balance feature to balance the pressure of two or more components as they are mixed. The pressures or flow rates of the two components are monitored. If there is a difference in pressure or flow rate greater than a specified amount, a bleed valve is opened for a short period of time to balance the flows. A computer with a touch screen is used to set the pressure and flow rate differences that trigger the bleed, and to set the time period for the bleed.

FIELD OF THE INVENTION

The present invention relates generally to systems for mixing liquid materials, and more particularly to systems for mixing and applying two or more liquid components to form a polyurethane based item.

BACKGROUND OF THE INVENTION

There are many situations where it is desirable to mix together two or more components to form a mixture that gets applied to form a structural component. For example, many structural items are formed from a polyurethane-based foam that is formed by mixing a urethane resin based liquid with a catalyst. When the two components mix they react to form a foam that causes the mixture to expand and eventually dry and harden into a structural element. These structural elements might include building insulation, molded foam products, and other items. In these situations it is necessary to carefully control the temperature, pressure, and flow rate of the materials being mixed.

A popular material for insulating commercial buildings and residential buildings is spray foam insulation. To create the spray foam insulation, two liquid components are mixed together as they are sprayed. As the two components mix together, they foam and expand and then relatively quickly dry and harden into a permanent insulation layer. The first liquid is commonly referred to as part A or component A and is typically comprised of isocyanates. The second component is typically referred to as part B or component B, and is typically a polymer resin. When component A and component B are mixed together at an elevated temperature, an immediate chemical reaction begins that releases gas that forms bubbles in the mixture. The mixture quickly hardens into a foamed solid.

In order to effectively apply such plural component insulations it is necessary to carefully control the temperature, pressure, and ratio of component A and component B as they are sprayed. If theses variables are not carefully controlled, it can result in an inefficient or wasteful use of the components, the resulting insulation product may be inferior, and the spraying equipment may be damaged. It can be difficult to optimally control these variables. The optimal inputs can vary during a single spraying session based on temperature changes—both environmental temperatures and equipment temperatures, especially as the equipment fully warms up. In the past, pressures have been adjusted by a user based on their observations of the quality of the foam. Electro-mechanical relay systems for operating check valves have been suggested for balancing the pressures of the two components as they are applied.

The efficient heating of the components to the appropriate temperature can be important. It is desirable to heat the components in a manner that is fast, and that maximizes the efficiency of the energy consumed in producing heat. In addition to heating the components, energy is required for moving the components through the system and ultimately to spray the components into place.

From the perspective of an owner of a spray rig, one of the important factors in how profitable operating the rig can be is the efficiency of the crew operating the rig. However, unless the owner is present, it can be difficult for the owner to know how efficient a crew is in their operation of the rig. For example, the efficiency could be better estimated if the owner knew how much time the crew spent spraying versus how much time was idle at a job site. Furthermore, there is danger that users of the system will “moonlight” by using the equipment at unauthorized jobs for which the owner is not being paid. Better yet would be if the owner could track the activity of the spray rig in real time from a home office.

When a mixing system, such as a spray foam insulation rig, shuts down for a long idle period between jobs, it is necessary to park the system. In particular, the pumps need to be returned to a “wet” rest position to avoid any material remaining in the pumps that could harden or crystallize and damage the pumps when they are restarted. The pressure should also be released from the system to avoid stress on the parts and to permit cleaning of the hoses and guns. Typically this is a manual process.

The components are supplied to the spray gun by a hose that includes a bundle including at least a conduit for each component. It is known to heat the conduits within the hose by using electrical resistance heaters. More recently, it has been realized that heated glycol or similar heat containing liquid can be provided to the hose to help maintain the A and B components at the proper temperature as they travel through the hose to the gun. Unfortunately, these heated hoses have been heavy and cumbersome both in storage and in use.

The present invention is an improvement over existing plural component spray rigs. It is an object of the present invention to improve the efficiency of the operation of a spray rig by automatically balancing at an appropriate ratio the pressure at which component A and component B are provided to a spray gun.

It is a further object of the present invention to efficiently heat component A and B by utilizing the heat generated by the engine and air compressor that are used to power the spray rig to provide heat to the components A and B.

It is a further object of the present invention to improve the efficiency of a spray rig by utilizing an air compressor to drive the pumps and other mechanisms used to move the components A and B through the system as well as to clear the components from the spray gun.

It is a further object of the present invention to record and log the spraying activity of the system to permit the efficiency of its use to be monitored.

It is a further object of the present invention to record and log the GPS coordinates of the spray rig as it is being used to monitor the use of the spray rig.

It is another object of the present invention to provide an automated system for returning the pump to a storage position and bleeding pressure from the system to when parking the system between jobs.

It is another object of the present invention to permit real time monitoring from a remote location of the activity of a mixing system.

It is a further object of the present invention to transfer data from the mixing system to a remote location.

It is yet another object of the present invention to permit control and reprogramming of the system from a remote location.

It is yet another object of the present invention to provide a lighter-weight heated hose for use transporting the components to the spray gun.

These and other advantages will be realized by the embodiments of the invention described and claimed herein. It should be understood that some embodiments may accomplish only one or a few of the objects. The invention should not be limited by the listed objects, except as reflected in the language of the claims.

SUMMARY OF THE INVENTION

According to one embodiment, the present invention is directed to a plural-component mixing system that includes first and second reservoirs containing first and second liquid components. A mixing apparatus is provided for mixing and applying the first and second liquid components. A supply system supplies the liquid components from the reservoirs to the spray gun. A programmable logic controller connected to the supply system controls the supply system and records information about use of the system. The system may include a touch screen interface in connection with the programmable logic controller to display information about the spraying system and to permit customized control of the spraying system. The system may include first and second bleed valves associated with the first and second liquid components respectively. First and second sensors may be included that are in communication with the programmable logic controller and that sense a quality of the liquid components. The programmable logic controller may control the first and second bleed valves based on the sensed qualities. The first and second sensors may be pressure sensors, wherein the programmable logic controller is programmed to compare the pressure at the first sensor with the pressure at the second sensor and to open the first bleed valve if the pressure at the first sensor exceeds the pressure at the second sensor by a specified amount and for opening the second bleed valve if the pressure at the second sensor exceeds the pressure at the first sensor by the specified amount. The programmable logic controller may be programmed to open the bleed valves for a specified period of time each time one of the bleed valves is opened. A user may be able to modify the specified period of time using the touch screen interface. The programmable logic controller may be programmed to automatically adjust the specified periods of time based on a determined property of the liquid components, such as the viscosity of the liquid components. The first and second sensors may be flow rate sensors, and the programmable logic controller may be programmed to open the bleed valves in response to the sensed flow rates to keep a ratio of the flow rates within a desired range. A GPS receiver may be provided in communication with the programmable logic controller to record the geographic data received from the GPS receiver when a spraying operation is initiated. The programmable logic controller may be programmed to record a time and duration of spraying operations.

According to another embodiment, the present invention is a plural-component mixing system that includes a reservoir of a first liquid component, the first liquid component being supplied to a first manifold, and a reservoir of a second liquid component, the second liquid component being supplied to a second manifold. A first pressure sensor monitors a pressure of the first liquid at the first manifold and a second pressure sensor monitors a pressure of the second liquid at the second manifold. First and second bleed valves are associated with the corresponding manifolds. A programmable logic controller compares the pressure at the first sensor with the pressure at the second sensor, and opens the first bleed valve if the pressure at the first sensor exceeds the pressure at the second sensor by a specified amount, and opens the second bleed valve if the pressure at the second sensor exceeds the pressure at the first sensor by the specified amount. The programmable logic controller may be programmed to open the first bleed valve for a first specified period of time each time the first bleed valve is opened, and the programmable logic controller may be programmed to open the second bleed valve for a second specified period of time each time the second bleed valve is opened. A user may be able to modify the specified periods of time using the touch screen interface. The programmable logic controller may be programmed to automatically adjust the specified periods of time based on a determined property of the liquid components, such as viscosity.

According to another embodiment, the invention is directed to a plural-component mixing system that includes a first reservoir containing a first liquid component and a second reservoir containing a second liquid component. A first flow-rate sensor monitors a flow rate of the first liquid and a second flow-rate sensor monitors a flow rate of the second liquid. A first bleed valve is associated with the first liquid component and a second bleed valve is associated with the second liquid component. A controller compares the flow rate at the first sensor with the flow rate at the second sensor, and opens the first bleed valve or the second bleed valve to bring a ratio of the first flow rate to the second flow rate into a desired range. A spray gun is in fluid communication with the reservoirs to spray and mix the liquid components to form a sprayed foam insulation.

According to another embodiment, the present invention is directed to a lightweight heated hose for use in applying plural component spray foam insulation. The hose includes a flexible, removable outer protective jacket. A flexible insulating jacket is contained within the protective outer jacket. First and second conduits are provided within the flexible insulating jacket. Each of the first and second conduits have an inlet for receiving a spray foam liquid component and an outlet for providing the spray foam liquid components to a spray gun. A third conduit is provided within the flexible insulating jacket. The third conduit has an inlet leg and an outlet leg. The third conduit contains a heated liquid to provide heat to the first and second spray foam liquid components in the first and second conduits. The conduits are formed from thin-walled tubing. The insulating jacket may be formed from fiberglass.

According to another embodiment, the present invention is directed to a plural-component mixing system comprising that includes first and second reservoirs containing first and second liquid components. Each of the liquid components has an associated bleed valve. A proportioner pump is provided to pressurize the liquid components. The proportioner pump has a preferred storage configuration. A programmable logic controller controls function of the bleed valves and the proportioner pump. The programmable logic controller is programmed to include a park function whereby the programmable logic controller causes the bleed valves to be opened and then causes the proportioner pump to move to the preferred storage configuration while the bleed valves remain open. Pressure sensors may associated with the liquid components to provide a signal to the programmable logic controller. The programmable logic controller may be programmed to maintain the bleed valves open during the park function until the pressure sensors indicate a sufficiently low pressure. A touch screen control may associated with the programmable logic controller to initiate the park function.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2show a spray rig5that includes a plural component insulation mixing system10according to one embodiment of the present invention. The mixing system10can be used to mix and apply insulation12. The rig5is provided on a portable trailer7. The trailer7includes a hitch9and wheels (not shown) that permit it to be towed by a towing vehicle (not shown) to a remote job site. As an alternative, the rig5could be included on a self-propelled vehicle, such as a truck. The walls of the rig5may be insulated. Ventilation openings and fans (not shown) may be provided to control the temperature within the trailer7. The mixing system10includes a first set of permanent reservoirs14that are intended to contain a first liquid component A. A rack15is also provided for containing portable drums of the first liquid component A. In practice the rig5may include both the permanent reservoirs14and the rack15, or may include only one or the other. Similarly, second permanent reservoirs18and rack19are provided to contain a second liquid component B. The reservoirs14and18may be large pressure vessels that will hold several drums worth of components A and B. Alternatively, in the case of a plural component mixture that contains more than two liquid components, the rig5could be provided with reservoirs or racks to hold additional types of components.

A liquid-cooled internal combustion engine24is provided to drive an air compressor26. Preferably the engine24has a shaft drive connected to the air compressor26to drive the air compressor26. Alternatively, a belt drive may be used. The engine24may for example, be a diesel engine, and the compressor26may be a screw compressor. According to the embodiment shown, the air compressor26is used to pneumatically power most of the components of the invention.

A proportioner pump28is driven by compressed air received from the compressor26. The proportioner pump28receives liquid components A and B from the reservoirs14and18and pumps them to a heat exchanger34. The components A and B are warmed in the heat exchanger34by coolant from the engine24and oil from the compressor26. The heated components A and B flow rearward to hoses (not shown) provided on the hose racks55.

A touch screen control66connected with a programmable logic controller (PLC) (not shown) is used to operate and monitor the system10. The touch screen control66is mounted at eye level for convenient access.

The rig5is preferably provided with safety equipment such as fire extinguishers27, a first aid kit (not shown) and an eye wash station (not shown). A tool cabinet29may also be included for storing tools. The heat exchanger34and other components may be hidden within a work bench31. The work bench31should be easily opened to provide access to the heat exchanger34and other components. Those of ordinary skill in the art will recognize many configurations for the various components within the rig5.

FIG. 3is a diagram that illustrates the primary components of the mixing system10that can be used to mix and apply insulation12, according to one embodiment of the present invention. The mixing system10includes a first reservoir14that contains component A16, which typically will be an isocyanate liquid. A second reservoir18contains component B20, which will typically be a polymer resin. The reservoirs14,18may be the 55-gallon drums in which components A and B are typically transported, or may be larger storage tanks which can hold a larger supply of the components. Additionally, and as will be discussed below, more than one reservoir may be used for storing each component in order to increase the volume of components that can be carried efficiently. A mixing apparatus, such as a spray gun22is provided as part of the system10in order to apply the insulation12. The gun22has a trigger (not shown) that allows a user to selectively spray components A and B such that they mix together to form the insulation12. The mixing system10provides an effective and efficient apparatus for moving the components A and B from the reservoirs14and18to the gun22. As an alternative to a spray gun, a mixing apparatus might include a variety of applicators or other mixing devices.

A liquid-cooled internal combustion engine24is provided to drive an air compressor26. Preferably the engine24has a shaft drive connected to the air compressor26to drive the air compressor. Alternatively, a belt drive may be used.

The air compressor26provides compressed air to various components in order to control and drive the components. A proportioner pump28is driven by the compressed air received from air compressor26. The proportioner pump28receives a low pressure supply of components A and B through inlet pipes30. The proportioner pump28pressurizes the components A and B and pumps them to heat exchanger34through outlet pipes32. Preferably the proportioner pump28will pressurize the components A and B to a pressure of about 1300 to 1400 pounds per square inch. The components A and B remain separate from each other within the proportioner pump28and the outlet pipes32. Preferably, the proportioner pump28will pump components A and B through the outlet pipes32at a ratio of about 1:1 on a by-volume basis. Alternatively, it may be possible to match the ratios of the components A and B to some other desired ratio. For example, it may be desirable to pump the components A and B on a 1:1 basis by weight rather than volume. It may also be possible to pump the components at a different specified ratio that works better for a given set of components. Furthermore, additional reservoirs with different liquid components could be added such that more than two components are kept in balance during a mixing and/or applying operation.

The air compressor26also provides pressurized air to the reservoirs14and18through pneumatic lines36. The pressurized air provided through pneumatic lines36is used to pump the components A and B through the inlet pipes30to the proportioner pump28. The air compressor26is also attached to a pneumatic line38that provides pressurized air to an agitator pump40. The agitator pump40is used to agitate and mix the resin20that makes up component B. The agitator pump40serves to recirculate component B20within the reservoir18to keep component B20in appropriate condition for mixing with component A to form the insulation. It should be appreciated that while the pneumatic lines, shown in broken lines withinFIG. 3, are illustrated as direct connections between the air compressor26and the various components, in practice the pneumatic lines would run through a manifold or manifolds that can selectively turn on and shut off the supply of pressurized air from the air compressor26to the various components. Additionally, while not shown inFIG. 3, the pressurized air from air compressor26may be used to control several valves that control the flow of components A and B through the system10. The air compressor26supplies pressurized air to the gun22through pneumatic line42. This pressurized air is used to clear the liquid components from the gun22so that they do not foul or clog the gun22. Therefore, when the trigger is depressed to spray the insulation12, the air flow from the air compressor26may be shut off, and the pressure of the components A and B may be relied upon to discharge the spray of insulation. When the trigger of the gun22is released, pressurized air blows through the gun22to clear the spray tip of any remaining component A and B in order to keep the gun22clean.

The engine24is cooled with an engine coolant, such as glycol. A coolant line44is used to supply coolant from the engine24into the heat exchanger34. The coolant remains in a closed loop, and passes through the heat exchanger34and then through a loop46that extends from the heat exchanger34to the gun22and then back to the heat exchanger34. The coolant then flows back from the heat exchanger34to the engine24through return line48. A pump (not shown inFIG. 3) may be provided within the coolant loop to help circulate the coolant from the engine through the heat exchanger to the gun22and back through the heat exchanger34to the engine24. Also, while not shown inFIG. 3, the air compressor26may have a loop of air compressor oil that circulates through the heat exchanger34to cool the air compressor26and heat the components A and B.

The components A and B are provided to the proportioner28at a relatively low pressure through inlet pipes30. The proportioner28pressurizes the components A and B and provides them to the heat exchanger34through outlet pipes32. Within the heat exchanger34heat is transferred from the engine coolant to the components A and B to heat the components A and B to a desired temperature. The components A and B then flow out of the heat exchanger34through heat exchanger outlets54which lead to bleed valves50and52. The bleed valves50and52could be cartridge valves or other types of valves. In operation the components A and B pass through the bleed valves50and52to insulated hose60that leads to gun22. Pressure sensors56and58measure the pressure of components A and B respectively at the bleed valves50and52. Pressure sensors56and58are connected either through wires, or by a wireless router, with computer62. The bleed valves50and52can be used to bleed off excess pressure from the components A and B to keep the pressures in balance. The bleed valves50and52have bleed lines64that lead back to the reservoirs14and18. If the pressure difference sensed by sensors56and58is too great, the control valve50or52that is associated with the higher pressure will be opened for a short period of time to bleed off pressure so that the pressures in the two lines are brought into balance.

The specified ratios are typically provided on a by-weight or by-volume basis. Therefore, pressure is only an indirect mechanism for determining the desired ratio. As an alternative, the sensors56and58may be flow rate sensors that measure the actual rate of flow of components A and B through the system. This may provide a more accurate mechanism for assuring the appropriate ratio of the components A and B than pressure. Therefore, a specified ratio of flow rates may be maintained by using the bleed valves50and52. If the ratio of flow rate of component A as measured at sensor56compared to the flow rate of component B measured at sensor58is too great (e.g., exceed 1.01) then bleed valve50can be opened for a specified period of time to bleed pressure from that line and reduce the flow rate of component A. Similarly, if the ratio of the flow rate of component A to the flow rate of component B is too small (e.g., less than 0.99), the bleed valve52can be opened for specified period of time to reduce the pressure in that line and hence reduce the flow rate of component B.

A touch screen66may be associated with the computer62to display information about the system10, and to permit a user to provide inputs to the computer62. Preferably the computer62will be a programmable logic controller (PLC). A user may specify how great the pressure difference sensed by sensors56and58must be before one of the control valves50or52is opened to bleed off pressure. Additionally, the touch screen66may be used to input a duration that the bleed valves50or52will be opened in response to a sensed pressure difference that is sufficient to trigger opening one of the valves50or52. For example, a user might input that a pressure difference of greater than 100 psi will trigger the higher pressure side to open its valve50or52. The user may also specify the time that the valve50or52will remain open, for example 1/10thof a second. It is critical that the pressure of the components A and B not be too far apart when they are combined together in the gun22as they are sprayed. If the pressure difference is too great, it can cause back flow from the higher pressure component into the outlet for the lower pressure component, which can result in foaming and expansion of the materials inside the system. That can lead to catastrophic failure. Therefore, the bleed valves50and52, in conjunction with the pressure sensors56and58and the computer62are used to maintain the system in appropriate balance.

Similarly, if the sensors56and58are flow rate sensors, a user may use the touch screen66to specify a desired range for the ratio of the flow rate of component A to component B. For example the range could be from 0.99 to 1.01. If the ratio is outside this range, the bleed valve50or52associated with the component with too high of a flow rate can be opened for a period of time that can also be specified by the user—for example, 0.1 seconds. If use of the system shows that frequent repeated bleed operations are occurring, a user can specify longer time period (e.g., 0.2 seconds) for the valve50or52to be opened on each occurrence. Or, if each bleed operation results in to great of a drop in pressure, a short time can be specified (e.g., 0.05 seconds). This also provides a convenient mechanism for dealing with different products, which might have a different specified ratio. Furthermore, both pressure sensors and flow rate meters could be used simultaneously. In the instance where both flow meters and pressure sensors are used in the balancing process, the flow rate would be the primary control variable for determining when to open a bleed valve. The reading from the pressure sensors would be for detecting errors in the system. For example if the pressure difference between the two fluids is greater than expected, it could be flow is impeded in one of the lines. Therefore a warning could be generated on the touch screen, or in severe cases, the PLC could cause the system to shut down entirely, so that the source of the problem can be identified and fixed.

The flow of components A and B through the system may be better understood by reference toFIG. 4. As seen in the component flow diagram ofFIG. 4, the system may be provided with two or more reservoirs100for storing component A102. The reservoirs100are each connected to a corresponding valve104that can be selectively opened or closed. Opening the valves104permits flow of component A102to the proportioner pump106. In practice, typically one of the valves104will be opened and one closed so that only a single reservoir100is being used at any one time. The valves104may be manually opened and closed, or may be controlled electronically, for example through a computer132. Component A102will be supplied to the proportioner106through valves104at a relatively low pressure, typically around 150 psi. The proportioner106will pressurize the component A102to about 1000 to 3000 psi. The pressurized component A102flows from the proportioner106through heat exchanger108where the component A102is heated to a desired temperature range for mixing with component B and spraying. The heated component A102flows from the heat exchanger to manifold110that includes a bleed valve112. The bleed valve112can be selectively opened to bleed off excess pressure. In practice, the bleed valve112may be two or more valves. When the valves are opened, they have lines that lead back to the reservoirs100so that as pressure and excess material are bled off, the excess component102is returned to the reservoirs100. The component A102flows from the manifold110to spray gun114through insulated hose116.

Reservoirs118, which may include two or more reservoirs118, contain resin component B120. Each of the reservoirs118has an associated agitator pump121which is used to circulate and agitate component B120so that component B120is ready for use. Valves122, which may be provided separately or as part of a single manifold, are used to selectively provide a flow of component B120from the reservoirs118to the proportioner pump106. Typically, only one of the valves122will be opened at any one time. Preferably, the proportioner pump106will be the same proportioner106as is used to pressurize component A102. The pressurized component B120flows from the proportioner106through heat exchanger108which preferably will be the same heat exchanger108that is used to heat component A102. The component B120flows from the heat exchanger108to manifold124that includes one or more bleed valves126. If the bleed valves are opened they will bleed off excess pressure from the component B120. When the bleed valve126is opened, the excess component B120that bleeds off is returned to one of the reservoirs118so that the material is not wasted. The bulk of the component B120flows through the manifold124to the gun114through insulated hose116where it can be sprayed and mixed with component A102to form the foam insulation.

The pressures of component A102and component B120are sensed by pressure sensors128and130respectively that are located at or within the manifolds110and124. The pressure sensors128and130are in communication with central processing unit132. Therefore, the pressures of the component A102and the component B120are continuously provided to the CPU132by the sensors128and130. The CPU132is programmed to compare the pressures within component A102and component B120at the manifolds110and124. The CPU132is also connected with bleed valves112and126, either directly or through a control mechanism, such that the CPU132can selectively open the bleed valves112and126. A user may input a pressure differential between component A and component B that will cause the CPU132to open the bleed valve112or126that is associated with the higher pressure component. A touch screen134or other input device such as a keyboard, may be used to input the triggering pressure differential. In addition, the time duration for which the bleed valve112or126will be opened upon each triggering event may be input by a user. Each of the bleed valves112and126may be set to be open for the same duration, or they may have different durations. In general, if the components have a relatively high viscosity, a relatively longer time period should be selected to open the bleed valves, and conversely when the components have a low viscosity, for example at elevated temperatures, a relatively shorter time period may be used for opening the bleed valves112and126.

While not shown inFIG. 4, the reservoirs100and118may be provided with sensors for measuring the remaining amount of component within the reservoirs100and118. For example, proximity sensors may be provided at the top of the reservoirs100and118to determine the distance between the top of the reservoirs118and100and the top of the fluid level of the component within the reservoir. The sensors may be connected with the CPU132and an output may be displayed on touch screen134to permit a user to monitor the amount of material remaining to be sprayed. Additionally, temperature sensors (not shown inFIG. 4) may also be provided at various locations to monitor the temperature of the components102and120. These temperatures may be communicated to the CPU132, which in turn may display that information on the touch screen134so a user can monitor the temperatures. Additionally, the CPU132may be programmed to control the flow of coolant to the heat exchanger108to regulate the temperature of the components102and120as desired.

These components may also be used to perform an improved “parking” function when the system is being shut down for an extended idle period, for example at the end of the work day, or when finishing at a work site. In order to prevent damage to the proportioner106, it is desirable to park the proportioner in its storage position. Typically this storage position will be one where the pump is at the end of stroke such that the seal remains wet and not excess component remains in the cylinder. If the proportioner106is adjusted to this park position it can over pressurize the component in the lines down stream from the proportioner, unless the bleed valves112and126are opened. Therefore, the present invention has a park feature programmed into the CPU (PLC)132. A user selects the park function using the touch screen134. The CPU132will then cause the bleed valves112and126to remain open while the proportioner106strokes to its storage position. The bleed valves112and126will remain open until the pressure sensors128and130sense that the pressure is at, or nearly at, zero. An indication may be given by the touch screen134that the parking function has been completed, and that it is safe to remove the hose116and gun114for cleaning.

FIG. 5is a schematic illustrating the pneumatic components of the mixing system10isolated from the other components for ease of visualization. Pressurized air is provided to the pneumatic components by an air compressor200. Preferably the air compressor200is directly driven by a shaft of an engine (not shown inFIG. 5). The air from the air compressor200should be treated to remove moisture and contaminants, for example, by a dehumidifier202and a filter204. Those of ordinary skill in the art will be aware of appropriate devices and methods for conditioning the air before providing it to the various pneumatic components. The conditioned air may be provided to a first manifold206. The first manifold206has outlets that provide the pressurized air first to a proportioner pump208and also to a second manifold210. The first manifold206may be provided with a safety valve to prevent the system from overloading the pneumatic components. Additionally, the first manifold206may be provided with utility outlets214such that a user can attach additional pneumatic components to the system as desired.

The second manifold210may be in communication with a computer216that can control various valves within the manifold210. The manifold210serves to control and selectively provide pressurized air to the various pneumatic components. For example, the second manifold210may selectively open and close a valve218that controls the flow of oil from the air compressor200to the heat exchanger (not shown inFIG. 5). Similarly, the second manifold210can be used to selectively provide pressurized air to coolant valve220that controls the flow of engine coolant to the heat exchanger (not shown inFIG. 5). By controlling valves218and220, through the manifold210, the CPU216can control the temperature of the components A and B. The pressurized air from the second manifold210can also be provided to the agitator pumps222that agitate the component B. The pressurized air from manifold210can also be supplied to a diaphragm pump214that is used to circulate the engine coolant.

The pressurized air from the second manifold210is also used to control the flow of components A and B to the proportioner pump208. This is accomplished by providing a supply of the air from the manifold210to the top of the reservoirs (not shown inFIG. 5). Pressurizing the reservoir tanks with the pressurized air in turn pressurizes the components A and B with the reservoir tanks encouraging the contents to flow to the proportioner pump208. In addition, the valves228and230that control the flow from the reservoir tanks226to the proportioner pump208are selectively actuated by pressurized air provided by the second manifold210as controlled by the computer216. Pressurized air is also provided to the gun232through the second manifold210. This pressurized air is used to blow out any excess liquid components remaining in the nozzle of the gun232after spraying the components.

FIG. 6is a diagram illustrating the elements of the system that are used to heat the components A and B isolated from the other elements of the system for ease of visualization. As seen inFIG. 6, components A and B are separately stored in storage tanks300and flow through heat exchanger302in separate conduits. While passing through the heat exchanger302, the components A and B are heated by engine coolant and air compressor oil that both also flow through the heat exchanger302. The engine coolant, typically glycol, is circulated through the heat exchanger302. The engine coolant travels from the engine304through a ball valve306that can be selectively opened or closed to help control the final temperature of the components A and B. After flowing through the heat exchanger302, the glycol engine coolant makes a loop through the insulated hose308in order to maintain the temperature of components A and B as they flow through the hose308to the gun310. The glycol coolant then flows back to the heat exchanger302on its return leg to the engine304, so that additional heat may be extracted from the coolant and passed onto the components A and B. A pump312may be included in the engine coolant loop to circulate the engine coolant. In the embodiments shown inFIG. 6, the pump312is located in a preferred location downstream from the heat exchanger302and upstream from the hose308.

Oil from the air compressor314also flows through heat exchanger302in a circulating loop. A valve316is provided to selectively control the flow of air compressor oil through the loop. Therefore, the system efficiently uses heat generated to operate the elements of the system to heat the components A and B.

FIG. 7is a schematic diagram illustrating the control and monitoring features according to one embodiment of the present invention. A computer central processing unit (CPU)400is provided to receive and log information from sensors provided as part of the system. Preferably the CPU400will be part of a programmable logic controller (PLC). The CPU400is also programmed to automatically control many of the elements of the system. A touch screen402is operationally connected with the CPU400to display output from the CPU400and permit a user to input data and responses into the CPU400. As an alternative, a display screen with a separate key board and monitor may be used to perform the functions of touch screen402. A communications device409, such as a wireless modem or cellular phone may be associated with the CPU400, such that a user can send and receive data from the CPU400.

The engine404has sensors connected with the CPU400so that the CPU400can monitor and log the time the engine404has been running, the engine temperature, the oil pressure, the voltage of the battery for the engine, fuel level of the engine, and the RPM rate. The air compressor406is connected to the CPU400so that the CPU400can monitor and log the air compressor's temperature and air pressure.

Various other sensors throughout the system also provide input that is monitored and logged by the CPU400. Most fundamentally, pressure sensors408provide an input of the pressures for components A and B. As described above, if there is a significant difference in pressures between components A and B, as measured by sensors408, the CPU400will send a signal that causes one of the bleed valves410to open for a short period of time to bleed pressure off of the higher pressure component. The touch screen402permits a user to specify how much of a pressure difference is required to trigger such a pressure bleeding event or what deviation from a desired flow rate ratio will trigger a bleeding event. The user may also specify through the touch screen402a period of time that the bleed valve410will be opened upon sensing a sufficiently large pressure difference to trigger the pressure bleeding event. The CPU400may also be connected with the gun412to monitor and log the spraying activity. This log information of spraying activity can be useful for comparing how efficiently an operator is using the system. The log information may be provided to a remote location, such as a home office, in real time, or nearly real time, via the communication device409. Therefore, a manager located in a home office can monitor the work being performed by a rig, or several rigs, without having to travel to the location of the rigs. The log information gathered by the system that can shared with the remote manager would include mixing time and idle time, the amount of material used, and the geographic location of the rig. The manager can address any difficulties immediately, rather than waiting for end of the day reports. Furthermore, the log information may be directly and automatically entered into a billing system to automatically generate a bill based on the time, location, and amount of material used.

Various temperature sensors414may also be connected with the CPU400. The temperature sensors414can provide information to the CPU400about the temperature of the components A and B so that the CPU400may control the flow of coolant and compressor oil into the heat exchanger to maintain a proper temperature. If the system cannot maintain the an appropriate pressure ratio or if the temperature of the components A or B reach an unsafe level, the controller can be programmed to automatically shut down the system to prevent damage. An error message will be displayed on the touch screen64indicating the reason for the shut down. A user can specify what pressure ratio and temperatures will trigger an automatic shut down. Furthermore, the CPU may be programmed to recognize when too many or too frequent bleed events are being required which indicates a problem somewhere in the system. A warning can be generated, or the system may automatically shut down. This can permit a user to solve a problem before damaging the equipment, or spraying faulty insulation that will need to be replaced at significant expense.

Additionally, an air temperature sensor (not shown) may be connected with the CPU400so that if the engine room temperature is too high, the system can automatically shut down to prevent damage or injury.

Proximity sensors may be provided on the component A and component B storage tanks to measure the level of liquid within the storage tanks. These proximity sensors416may be connected with the CPU400so that the amount of materials remaining can be monitored and displayed on the touch screen402.

A GPS receiver unit418may also be provided as part of the plural component spraying system. This GPS unit418may be connected to the CPU400so that the spraying data may also be associated with a particular geographic location. In addition, or in the alternative, the GPS unit418may provide information back to a home base or remote location, so that the location of the unit may be monitored at all times. This can be important information to ensure that the mixing system is being used in the most efficient manner, and is not being used in any unauthorized locations.

The communications device409may permit the CPU400to be reprogrammed from a remote location, such as a home office. Therefore, if the parameters or characteristics of one of the components change, for example if a new vendor is being utilized, the operational features of the system could be revised to match the new parameters. This could be especially useful for updating an entire fleet of rigs quickly. For example, if a new component B is being utilized that has a higher viscosity that the previously used component B, the system could be modified to open the bleed valves for a longer period of time each time they are opened. This could be done from the home office on all rigs in the fleet without the need for the manager to go to the rigs or have the rigs come to the home office.

FIGS. 8 and 9illustrate a manifold450that is used to automatically balance the pressure between components A and B according to one embodiment of the present invention. The manifold450includes a solid body452that includes an inlet passage454for receiving a compressurized component A or component B. A bleed valve456is provided in the inlet passage454. The bleed valve456is adjustable to either prevent or permit flow of the pressurized component through an outlet bleed line458. The inlet passage454is connected with a central passage460(only visible in cross-section view7). The central passage460connects with two outlet passages462and464. Each of these outlet passages462and464may be connected to its own mixing apparatus (e.g., spray gun) (not shown inFIG. 6or7). Accordingly two spray guns may be utilized off of the same manifold450. The central passage460also leads to an accumulator466that serves to moderate and maintain a constant pressure within the central passage460and outlet passages462and464.

A pressure sensor470is provided in the central passageway of the manifold450to monitor the pressure of the component A or B as it is provided to the manifold450. The bleed valve456is automatically controlled by a computer that compares the pressures of the component A or B provided to the manifold with a similar pressure of the other component A and B that is provided to a similar manifold. If the pressure of the component provided to manifold450exceeds by more than a specified amount the pressure of the component provided to another similar manifold, then bleed valve456is opened to permit the component to flow out the bleed line458for a short period of time to reduce the pressure in the system. Typically, opening the valve456for a tenth of a second or less will be sufficient to reduce the pressure within the central passage460by 100 psi or more. It should be understood that the manifold450shown inFIGS. 8 and 9is for a system that includes mixing apparatuses (e.g., two spray guns) and one supply tank. Those of skill in the art will recognize that several various numbers of orifices may be provided to the central passage depending upon how many mixing apparatuses and supply tanks are being utilized. It may be preferable to make a standardized manifold450with a large number of orifices that can be selectively plugged, for example by a threaded cap, if not needed.

FIG. 10shows a cross-sectional view of a hose500according to a preferred embodiment of the present invention. The hose500has an insulated outer jacket502that should be flexible and durable and may be formed from a variety of materials, such as nylon, Gore-Tex, or other similar fabric. In a preferred embodiment, the outer jacket502has a hook and loop fastener (e.g., Velcro) seam504that can be selectively opened and closed to insert the hose components. The hose500includes within it conduit lines506and508that carry component A and B respectively to the gun. In order to help maintain components A and B within the conduits506and508at the desired temperature, a loop of glycol coolant is also provided within the hose500. The loop of glycol coolant includes in cross-sectional view a first conduit510that carries engine coolant that is flowing in the same direction as the components A and B within conduits506and508. In cross-section, a second glycol conduit512is the return leg of the glycol loop that contains glycol flowing the opposite direction as the components A and B in conduits506and508. An air conduit542for providing pressurized air to an attached mixing device, such as a spray gun, is also provided within the bundle. The conduits506,508that carry the pressurized components A and B may be formed from Teflon and woven stainless steel. Preferably the conduits506and508will have an inner diameter of about 0.375 inches. The glycol conduit510and512is a thin-walled PVC tubing having an inner diameter of about 0.375 inches and an outer diameter of about 0.5 inches. The air conduit42may also be formed from thin-walled PVC tubing having an inner diameter for about 0.25 inches. These thin-walled PVC tubes are a significant improvement over prior art designs that utilized rubber or other thicker-walled tubes. They result in a smaller diameter, lighter hose for easier storage and manipulation. Conduits506,508,510,512, and542are all tightly bundled together and wrapped by a fiberglass insulating jacket514. The fiberglass insulating jacket514should be flexible to permit the hose to be easily manipulated as used. The bundle of conduits within the fiberglass insulating jacket514can be placed within the outer jacket502to protect, and further insulate the bundle.

The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives. For example, while a plural-component structure for use in applying insulation has primarily been described, the features and structures described herein could also be used for mixing more than two components, and for forming items other than insulation. For example, rather than using a spray gun to spray the mixture, a stream or poured mixture could be used for applying the mixture into a form or mold to form a variety of foamed parts.