Patent Application
20230398387
The present disclosure relates generally to an electric fire truck chassis. The electric fire truck chassis is powered by a battery array for movement of the fire truck chassis (by driving). The electric fire truck chassis carries a pump for pumping firefighting agent or firefighting fluid (typically water, with or without fire-suppression foam) for firefighting. The pump is powered by the battery array.
A typical fire truck chassis has traditionally been powered by an internal-combustion engine, which provides power for movement of the fire truck chassis and may provide power to a pump carried by the fire truck chassis. The pump of such a fire truck chassis is typically powered via a conventional power takeoff operatively connected to the internal-combustion engine. Alternatively, a pump on a traditional fire truck chassis may be powered by a dedicated internal-combustion engine.
Electric fire truck chassis have recently become available and may become more prevalent over time. Under current technology, the time required to charge the battery array of an electric fire truck chassis to near capacity is longer than the fueling time of a fire truck chassis with an internal-combustion engine and a fuel tank. Furthermore, the battery array of an electric fire truck chassis may have a lower energy-storage capacity than a typical fuel tank in a fire truck chassis with an internal-combustion engine. The electric fire truck chassis and the electric pump system of the present disclosure may provide advantages over known electric fire truck chassis. These advantages may include efficient use and conservation of the energy-storage capacity of the battery array of the electric fire truck chassis through the disclosed pump system for use on the electric fire truck chassis. In some embodiments, the electric fire truck chassis may be a hybrid fire truck chassis, wherein a traditional internal combustion engine drives a generator to provide some battery re-charging capability. Aspects of the present disclosure would also provide advantages to a hybrid fire truck chassis, reducing the electrical load, increasing battery life, and reducing generator run-time requirements.
Briefly stated, one aspect of the present disclosure is directed to a firefighting apparatus. The firefighting apparatus includes a movable fire truck chassis and a battery array movable with the movable fire truck chassis and operatively connected to provide power for operating at least one pump of the firefighting apparatus. A pre-connect pump has a pre-connect inlet and a pre-connect outlet and is electrically powered by the battery array. A controller is operatively connected to the pre-connect pump and configured to control the pre-connect pump under a standby condition selected to maintain the firefighting apparatus in a state of readiness to pump firefighting fluid. The controller reduces a power-consumption rate of the pre-connect pump while maintaining the standby condition as compared to operating the pre-connect pump under an idle condition. The standby condition requires pumping by at least one pump within the firefighting apparatus for maintenance of the standby condition.
In another aspect, a method is disclosed for operating electrically powered pumps of a firefighting apparatus having a movable fire truck chassis and a battery array movable with the movable fire truck chassis. The battery array is operatively connected to provide power for at least one component of the firefighting apparatus. The firefighting apparatus has a drive motor carried by the movable fire truck chassis and operatively connected to drive movement of the movable fire truck chassis. The drive motor is operatively connected to receive power from the battery array. A pre-connect pump has a pre-connect inlet and a pre-connect outlet and is electrically powered by the battery array. The method comprises operating a controller, the controller being operatively connected to a pre-connect pump having a pre-connect inlet and a pre-connect outlet. The controller controls activation of the pre-connect pump under a standby condition selected to maintain the firefighting apparatus in a state of readiness to pump firefighting fluid, with the controller reducing a power-consumption rate of the pre-connect pump as compared to operating the pre-connect pump under an idle condition, while maintaining the standby condition, and with the standby condition requiring pumping by at least one of the electrically powered pumps for maintenance of the standby condition.
The following detailed description will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings various embodiments, including embodiments which may be presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:
Certain terminology is used in the following description for convenience only and is not limiting. The words “right,” “left,” “lower,” and “upper” designate directions in the drawings to which reference is made. The words “inner” and “outer” refer to directions toward and away from, respectively, the geometric center of an object and designated parts thereof. Unless specifically set forth otherwise herein, the terms “a,” “an,” and “the” are not limited to one element but instead should be read as meaning “at least one.” “At least one” may occasionally be used for clarity or readability, but such use does not change the interpretation of “a,” “an,” and “the.” Moreover, the singular includes the plural, and vice versa, unless the context clearly indicates otherwise. As used herein, the terms “proximal” and “distal” are relative terms referring to locations or elements that are closer to (proximal) or farther from (distal) with respect to other elements, the user, or designated locations. “Including” as used herein means “including but not limited to.” The word “or” is inclusive, so that “A or B” encompasses A and B together, A only, and B only. The terms “about,” “approximately,” “generally,” “substantially,” and like terms used herein, when referring to a dimension or characteristic of a component, indicate that the described dimension/characteristic is not a strict boundary or parameter and does not exclude minor variations therefrom that are functionally similar. At a maximum, such references that include a numerical parameter would include variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit thereof. “Battery array” includes any combination of one or more rechargeable batteries (including but not limited to lithium-ion, nickel-metal hydride, lead-acid, developed to date or hereafter) operatively connected to a movable fire truck chassis, or to one or more electrical components thereof, to provide energy storage. All of the batteries of a battery array may be adjacent to one another; or the batteries of the battery array may be divided among one or more locations and/or housed within one or more housings or units. “Firefighting fluid” refers to firefighting agent comprising liquid and/or foam and usable for firefighting and includes, but is not limited to, water (regardless of the presence of solid or liquid impurities therein) and mixtures of water with foams or foaming agents for firefighting. An “idle condition” is an operating condition requiring operation or rotation of an engine or pump, as when pumps or other devices are connected to an internal-combustion engine, which must run (idle) to maintain the system in a selected standby condition. Various pumps are designated herein as a main pump 80, a large-diameter-hose pump 100, a pre-connect pump 120, and a pressure-maintenance pump 260; these designations refer generally to the functions and roles of such pumps in the firefighting apparatus disclosed herein, rather than to specific characteristics that might be read into to each designation. The terminology set forth in this paragraph includes the words noted above, derivatives thereof, and words of similar import.
With respect to fire truck chassis in general, regardless of the power source thereof, fire-suppression hoses and nozzles and connected pump systems may spend a considerable amount of time in a standby condition. The standby condition is a zero-flow state or a near-zero-flow state or a low-flow state wherein firefighting fluid is not being discharged onto a fire—for example, during rescue, search, or setting up or breaking down suppression operations. The selected standby condition may be determined to maintain the firefighting apparatus in a state of readiness to pump firefighting fluid. While firefighting fluid is not being discharged onto a fire under the standby condition, the fire-suppression hoses and nozzles and connected pump systems may be kept ready to begin supplying firefighting fluid to that the firefighting apparatus can supply firefighting fluid quickly on demand. Although a slight delay of a few seconds in providing firefighting fluid upon demand may not cause an issue with a rigid fire hose, a delay may be critical if a lay-flat hose is used. A lay-flat hose, which collapses when not under pressure, may develop a kink resistant to flow within less than one second; so a firefighting apparatus for safe use with a flexible hose or a lay-flat hose may preferably maintain positive pressure to maintain the lay-flat hose in an expanded condition. As a result, a system with a lay-flat hose must be configured to supply firefighting fluid essentially immediately, within less than one second, or less than one-half second, or less than 0.1 second. If a rigid hose is being used, a short delay may not be an issue, and a pump system may be adequate if able to supply firefighting fluid within one to two seconds of detecting demand.
In one aspect, the present disclosure is directed to firefighting apparatus including a pump system 10 that may substantially reduce the energy used for pumping firefighting fluid in the standby condition (the zero-flow or near-zero-flow states) as compared to a traditional non-electric fire truck chassis with one or more pumps driven by one or more internal-combustion engines. The pump system 10 may be especially advantageous when including a plurality of pumps with varying capacities, allowing for the running of the most efficient pump or pumps for a particular use scenario.
In another aspect, the present disclosure is directed to firefighting apparatus including a pump system 10 and a movable fire truck chassis such as an electric fire truck chassis 12 that may provide more efficient pumping of firefighting fluid by providing one or more pumps 80, 100, 120, 260, with each pump 80, 100, 120, 260 including or powered by an electric motor and adapted and/or powered in a manner suited for particular use scenarios, rather than utilizing the approach used for pumping operations powered by an internal-combustion engine, where the internal-combustion engine must be run at a minimum idle speed, and where energy efficiency may be less critical. As noted more generally above, the electric fire truck chassis 12, which is powered by a battery array 14 (including at least one battery, as defined above), may have a lower energy-storage capacity than a traditional fire truck chassis powered by an internal-combustion engine. Further, a substantial recharge of the battery array 14 may take more time (and may be less conveniently available) that refueling of a traditional fire truck chassis. For at least these reasons, the energy-efficient pump system 10 may be particularly advantageous when used for an electric fire truck chassis 12.
In one aspect, referring to
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The controller 200 may be operatively connected to the pressure-maintenance pump 260 and the pre-connect pump 120 and configured to control the pressure-maintenance pump 260 and the pre-connect pump 120 under the standby condition while reducing a combined power-consumption rate of the pre-connect pump 120 and the pressure-maintenance pump 260 as compared to operating the pre-connect pump 120 under the idle condition. In another embodiment, the controller 200 may be operatively connected to the pressure-maintenance pump 260 and/or the pre-connect pump 120 and configured to control the pressure-maintenance pump 260 to maintain the standby condition while operating only the pressure-maintenance pump 260. The pressure-maintenance pump 260 may have a pressure-maintenance power consumption to maintain the standby condition, and the pressure-maintenance power consumption may be less than a pre-connect minimum power consumption required to operate the pre-connect pump 120 to maintain the standby condition.
Continuing to refer to
A selector-valve device 40 may comprise a single three-way valve configured to allow the main pump 80 to be fluidly connected to a selection of either of two sources of firefighting fluid—for example, an unpressurized water supply 20 or a pressurized water supply 60. Alternatively, the selector-valve device 40 may comprise two valves, each configured to control a fluid connection to a respective one of the unpressurized water supply 20 and the pressurized water supply 60. The selector-valve device 40 has a first selector inlet 42 and a second selector inlet 42′ and a selector outlet 44. The selector outlet 44 is in fluid communication with the main inlet 82, and the selector inlets 42, 42′ may be configured to be connected in fluid communication with an unpressurized supply of firefighting fluid such as the unpressurized water supply 20, or a pressurized supply of firefighting fluid such as the pressurized water supply 60. The controller 200 may receive firefighting-fluid-supply data indicating a connection of the unpressurized water supply 20 or the pressurized water supply 60 in fluid communication with the selector outlet 44. The controller 200 may be configured to control the pressure-maintenance pump 260, the pre-connect pump 120, the large-diameter-hose pump 100, and/or the main pump 80 based in part on the firefighting-fluid-supply data.
The unpressurized water supply 20 may be, for example, a water tank carried on the electric fire truck chassis 12, or another unpressurized source of firefighting fluid such as a water tank not carried on the electric fire truck chassis 12, or a river, or a pond. The pressurized water supply 60 may include a fire hydrant, a piping system, or another pressurized system supplying water under pressure (typically at about 50-100 psi). Based on the setting of the selector-valve device 40 (for example, two or more selector valves, where present), the unpressurized water supply 20 or the pressurized water supply 60 may be fluidly connected to the main pump 80, which may be installed on the electric fire truck chassis 12 and may be capable of supplying a substantial flow of firefighting fluid—for example, about 1250 GPM (gallons per minute) at a pressure of 50 psi, while consuming a maximum of, for example, about 36 WHP (water horsepower). For reference, water horsepower may be computed as the product of pressure (psi) and flow rate (gallons per minute), divided by 1714 (a unit-conversion factor). The main pump 80 may receive firefighting fluid through a main inlet 82 thereof and may discharge firefighting fluid through main outlet 84 thereof. A main check valve 140′ may be operatively connected in fluid communication with the main outlet 84 and the pre-connect inlet 122 and may be configured to prevent back flow through the main pump 80. This arrangement enables a pressure-maintenance pump 260 (discussed below) to maintain pressure without causing backward flow through the main pump 80. Where the pressurized water supply 60 is available and selected, the main pump 80 may be controlled to run at a selected speed, which may be the lowest speed compatible with flow and pressure requirements of any discharge nozzles and related fluid connections in fluid communication with the main outlet 84 of the main pump 80, which are discussed below. If the pressurized water supply 60 provides sufficient pressure for the selected discharge nozzles and related fluid connections, then the main pump 80 may run only as needed (slowly and/or intermittently, to limit, reduce, or minimize power usage), or the main pump 80 may not run at all (for a particular water supply 60).
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A discharge valve 114 may be operatively connected between the pre-connect outlet 124 of the pre-connect pump 120 and the hose 160. In an embodiment wherein the hose 160 is a lay-flat hose, the discharge valve 114 may serve to trap pressure in the hose 160, allowing the hose 160 to remain in the expanded state without receiving pressurized firefighting fluid from the pre-connect pump 120, or by receiving a reduced supply of pressurized firefighting fluid from the pre-connect pump 120—in either case, contributing to reduced power usage by the pre-connect pump 120 and preservation of the charge of the battery array 14. Similarly, a discharge valve 114′ may be operatively connected between the large-diameter-hose outlet 104 of the large-diameter-hose pump 100 and the hose 160′. In an embodiment wherein the hose 160′ is a lay-flat hose (collapsible hose), the discharge valve 114′ may serve to trap pressure in the hose 160′, allowing the hose 160′ to remain in the expanded state without receiving pressurized firefighting fluid from the large-diameter-hose pump 100, or by receiving a reduced supply of pressurized firefighting fluid from the large-diameter-hose pump 100—in either case, contributing to reduced power usage by the large-diameter-hose pump 100 and preservation of the charge of the battery array 14.
An accumulator 161 may be operatively connected between the pre-connect outlet 124 of the pre-connect pump 120 and the hose 160—for example, downstream from the discharge valve 114 in fluid communication with the nozzle 180. The accumulator 161 may provide fluid pressure or fluid flow upon a pressure drop or fluid movement at the accumulator 161. Similarly, an accumulator 161′ may be operatively connected between the large-diameter-hose outlet 104 of the large-diameter-hose 100 and the hose 160′—for example, downstream from the discharge valve 114′ in fluid communication with the nozzle 180′. The accumulator 161′ may provide fluid pressure or fluid flow upon a pressure drop or fluid movement at the accumulator 161′.
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The controller 200 may be operatively connected to and may control the operation of the main pump 80, the pre-connect pump 120, the large-diameter-hose pump 100, and the foam-injection pump 240 for efficient use of the battery array 14, based on conditions within the pump system 10 and demand for firefighting fluid and/or a lack of demand for firefighting fluid. The controller 200 may be operatively connected to the pre-connect pump 120 and configured to control the pre-connect pump 120 under a standby condition selected to maintain the firefighting apparatus in a state of readiness to pump firefighting fluid, with the controller 200 reducing a power-consumption rate of the pre-connect pump 120 while maintaining the standby condition as compared to operating the pre-connect pump 120 under an idle condition as noted above, requiring continuous operation or rotation of the pre-connect pump 120 as in a conventional arrangement including an internal-combustion engine, wherein the standby condition requires pumping by at least one pump within the firefighting apparatus for maintenance of the standby condition.
The controller 200 may be operatively connected to an interface 202, which may be a touch screen, keyboard, switch or switches, or other input device capable of providing input to the controller 200. The interface 202 may be used to provide information to the controller 200 regarding the available firefighting fluid source(s) and/or the desired flow through any connected nozzles and other devices comprising the pump system 10. The controller 200 may be operatively connected to a firefighting-fluid-demand sensor 182, 182′, which may be a sensor capable of detecting demand for firefighting fluid to be supplied to a nozzle such as the nozzle 180, 180′. The firefighting-fluid-demand sensor 182, 182′ may be operatively connected to, or included with, the corresponding nozzle 180, 180′. For example, the firefighting-fluid-demand sensor 182, 182′ may comprise a nozzle-valve-position sensor operatively connected to a nozzle valve 184 of the nozzle 180 to detect an operating position thereof directly. The firefighting-fluid-demand sensor 182, 182′ may alternatively detect the operating position of the nozzle valve 184, 184′ by being operatively connected to detect an operating position of a bail, lever, handle, or other mechanism used to open and close the nozzle valve 184, 184′. Alternatively, the firefighting-fluid-demand sensor 182, 182′ may comprise a flow switch or a flowmeter sensor detecting flow of firefighting fluid through the nozzle valve 184, 184′ or hoses 160, 160′ or other hoses, pipes, or fluid connections providing firefighting fluid thereto. Still further alternatively, the firefighting-fluid-demand sensor 182, 182′ may be a sensor configured to detect a pressure drop through an orifice of the nozzle 180, 180′ or through an orifice fluidly connected to the nozzle 180, 180′ or in any of the hoses or fluid connections providing firefighting fluid thereto, or through the nozzle valve 184, 184′. A firefighting-fluid-demand sensor 182′″ may be positioned and configured to detect a pressure drop through a discharge valve 114, 114′ and may provide information indicating a demand for firefighting fluid to the controller 200. A firefighting-fluid-demand sensor 182″ may be positioned at main outlet 84 and configured to detect flow from the main pump 80 and to provide information indicating a demand for firefighting fluid to the controller 200.
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Maintaining the pump system 10 in the standby condition may require maintaining appropriate pressure in the pump system 10 to maintain the hose 160 in a ready state—preferably in an expanded, pressurized, non-flat state, where the hose 160 is a lay-flat hose. Alternatively, maintaining the pump system 10 in a second standby condition may require maintaining a particular pressure compatible with rapid acceleration of a discharge pump such as the pre-connect pump 120. The pump system 10 may include the pressure-maintenance pump 260, which may be a small-capacity electric pump with an inlet 262 and an outlet 264. The pressure-maintenance pump 260 and may be operatively connected to the battery array 14 and to the controller 200 and may be operated to maintain sufficient pressure to maintain the standby condition in the hose 160, where the hose 160 is a lay-flat hose, to maintain the lay-flat hose in an expanded state. Then, when a nozzle such as the nozzle 180 is opened, a larger electric pump such as the pre-connect pump 120 may be brought up to speed to provide an appropriate flow of firefighting fluid. As a potential further measure to reduce energy consumption, the hose 160 may be a non-collapsible or booster-type hose that retains a round shape or another expanded shape even when not under pressure, with the result being that the pressure in the hose 160 in the standby condition, and therefore the power consumed in maintaining pressure in the hose 160 in the standby condition, are further reduced. Alternatively, the hose 160 may be a lay-flat hose requiring a lower-than-standard standby pressure to maintain its expanded, non-collapsed state; such a hose 160 would also result in reduced standby pressure and reduced energy consumption as compared to a standard lay-flat hose.
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After completing step 214, the processor 200 can perform step 216, which is an additional evaluation of whether firefighting fluid is demanded at one or more nozzles. At step 216, the controller 200 may evaluate demand for firefighting fluid (water) based on a signals from a nozzle-valve-position detector, or based on a pressure drop across any nozzle, or based on a signal from a flow meter or flow sensor, or the like. When there is demand for firefighting fluid at a nozzle such as the nozzle 180, 180′, and one or more pumps are in operation, the controller 200 may evaluate at step 218 (and may do so repeatedly) the flow of firefighting fluid available at any nozzle where flow of firefighting fluid is demanded—for example, at nozzle 180, 180′. The flow of firefighting fluid may be evaluated by determining or estimating the flow of firefighting fluid based on one or more measured quantities, such as pressure readings at various locations in the system. The flow evaluation may include an intermediate determination or calculation of the flow of firefighting fluid, with the adequacy of the flow being determined by comparing the estimated or computed flow rate to the desired flow rate. The flow of firefighting fluid may be computed or estimated based on a pressure reading at one or more locations in the pump system 10, in combination with a known arrangement (connected hoses and devices) and state (valves open and closed) of the system. If the controller 200 evaluates the flow of firefighting fluid as being too low (based on one or more of the measured quantities being too low), then the controller 200 may proceed to step 220 and send one or more signals to increase the speed of one or more pumps fluidly or operatively connected to the flow being detected in evaluating the flow of firefighting fluid. If the flow of firefighting fluid is not evaluated as being too low at step 218, the controller 200 may evaluate at step 222 whether the flow of firefighting fluid is too high. If the flow of firefighting fluid is evaluated at step 222 by the controller 200 as being too high (based on one or more of the measured quantities being too high), then the controller 200 may proceed to step 224 and send one or more signals to decrease the speed of one or more pumps fluidly or operatively connected to the flow being detected in evaluating the flow of firefighting fluid. The controller 200 may then return to step 216 and again evaluate whether firefighting fluid is demanded at a nozzle or other location in the firefighting apparatus. Alternatively or in addition, the controller 200 may evaluate the adequacy of a flow of firefighting fluid based on one or more measurements of pressure and/or another direct measurement, determining appropriate signals to control the pumps based on measurements of pressure or other measured quantity, rather than computing or estimating fluid flow as an intermediate step before determining the adequacy of the flow of firefighting fluid. The flow evaluation may thus be performed by comparing one or more measured pressures to one or more selected pressures, which are selected to provide a desired flow of firefighting fluid, without an intermediate determination or calculation of the flow of firefighting fluid.
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Note that because main pump 80, the large-diameter-hose pump 100, and the pre-connect pump 120 are powered by electric motors (preferably electric motors integrated therewith as a unit), the pumps are able, upon detection of demand or a need for increased flow of firefighting fluid, to accelerate and increase flow of firefighting fluid quickly from a low operating speed or even from a stop. A pump with a low mass moment of inertia (in relation to its pumping capacity) may accelerate quickly to the speed needed to provide the required pressure and flow. A close-coupled pump mounted to a high-torque electric motor (or having such a motor integral thereto) may allow the pump to accelerate to an appropriate speed and to provide the demanded flow of firefighting fluid. Further, a plurality of electric pumps of various capacities may be connected through electrical circuits to the battery array 14 and operated as needed, completely independently from one another, with the pumps consuming power from the battery array 14 only when in operation. The plurality of pumps may be arranged to provide liquid flow in parallel to each other, offering flexibility to use only the pumping power necessary to supply liquid to particular nozzles, at the particular flow rates and pressures, as needed for a particular use of the pump system 10. This mode of operation is quite different from the operation of a traditional fire truck chassis powered by an internal-combustion engine, in which the internal-combustion engine must be kept in an idle condition, with the internal combustion engine idling (running, at the cost of substantial energy usage) in order to maintain a connected pump system in a standby condition (with no demand for firefighting fluid). With a traditional fire truck chassis, a pump connected to the internal-combustion engine may also need to be kept in operation (with pressure relief) to maintain a selected standby condition, even if no liquid is demanded at any of the nozzles.
The methods disclosed herein may be adapted to and performed in conjunction with any apparatus disclosed herein. Any apparatus disclosed herein may have a controller 200 adapted to implement any method disclosed herein.
In the pump system 10, pumps on the discharge side—for example, pre-connect pump 120 and other pre-connect pumps, where included—may be designed for optimum efficiency for a particular intended application (flow rate, pressure, etc.) and need not be compromised for lift performance (working across a broader range of pressures), which could lower efficiency. In certain embodiments, the pump system 10 could include a small electric pump for each discharge valve or nozzle, for example, when a manifold 1100 is used, as shown in
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present disclosure as defined by the appended claims.
This application claims the benefit of priority under 35 USC § 119(e) of U.S. Provisional Patent Application No. 63/350,583 filed Jun. 9, 2022; and the contents of the application identified in this paragraph are incorporated into the present application by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63350583 | Jun 2022 | US |
