Patent Application
20060131038
1. Field of the Invention
The present invention is generally related to the field of remote pressure monitoring and control and more particularly to a hose pressure monitor/telemetry system.
2. Description of the Prior Art
In the use of high-pressure hoses and in particular that of fire hoses, it is very important to maintain constant water pressure at the nozzle. If the pressure changes without warning, a firefighter or other hose user will be faced with either not enough flow to perform the job or a potentially dangerous over-pressure situation. It is known in the art to provide a pressure monitor on a fire engine at the output of the pump that performs a governor operation on the pump throttle to attempt to maintain a constant pressure. This method suffers from the fact that the pressure is being monitored at the pump rather than at the nozzle. The pump operator estimates the pressure at the nozzle by taking into consideration the friction loss for the hose length (i.e., hose diameter, hose length). The friction loss itself is dependent on the water flow rate.
For the case of a flow-adjustable fog nozzle or other nozzle, if the person at the nozzle inadvertently changes (or requires more water flow but cannot communicate this to the pump operator) the water flow setting of the nozzle, there will be an overpressure or under-pressure condition. Also in fire work, a nozzle can be at a totally different elevation than that of the pump, thus requiring a correction to the pump discharge pressure (i.e., one half pound per square inch per foot of elevation). For example, a firefighter might be using a nozzle on the end of a hose that is several stories above the level of the pump (or in the alternative, below the level of the pump). Also, the hose can encounter numerous bends and other obstacles that cause the pressure to be different at the nozzle from that at the pump and very difficult to estimate.
In most fire usage, the pressure is increased or decreased only based on feedback from direct person-to-person communications with the nozzle person. This can be very dangerous because the firefighters operating the nozzle may not have sufficient water flow to extinguish the fire or protect themselves with a proper fog pattern The nozzle can have too much pressure that can fatigue the firefighters or throw them back. An overpressure situation also makes hose handling more difficult since it becomes more rigid. Not having the correct pressure also causes delays in response.
What is badly needed is a method and system for automatically and continuously monitoring pressure directly at the nozzle, relaying that information back to the pump location, and optionally performing automatic closed-loop control of the pump.
The present invention relates to a system for remotely monitoring the pressure or other quantity at a hose nozzle that may include a pump providing liquid pressure to a nozzle, at least one sensor in proximity to the nozzle where the sensor monitors the pressure or other quantity at the nozzle, and a radio transmitter coupled to the sensor that transmits messages back to at least one central station pertaining to the nozzle pressure or other measured quantity. The present invention includes the option of closed-loop feedback control of the water pressure that using any type of sensor to monitor any quantity at a nozzle.
Several figures and illustrations have been presented to aid in the understanding of the present invention. The scope of the present invention is not limited to what is shown in the figures.
The present invention relates to a method and system to directly measure water pressure at a nozzle (in particular, a fire hose nozzle) and provide this information at the pump panel for use by the pump operator, or provide this information to other locations, or optionally automatically control a pump through a closed-loop feedback arrangement. In the manual case, the pump operator can read the pressure and manually adjust the pump. In the automatic case, a feedback loop can maintain a constant desired pressure at the nozzle. The present invention also provides optionally additional pressure monitoring locations (such as at the pump discharge) to locate problems in the system such as kinks in the hose and leaks. These problems can be diagnosed by reporting the differential pressure between the pump discharge and the nozzle. A pressure sensor can also be used at the pump intake to provide that pressure to a relay fire engine providing a continuous water supply.
The present invention normally uses wireless communications between the nozzle and a receiver unit located near the pump preferably on the fire engine. The communications should preferably be by wireless such as radio in a frequency band that is not primarily line-of-sight. While infrared or microwave line-of-sight communications could be used in some situations, these techniques would not generally be useful in a fire situation with firefighters inside a building. It is also within the scope of the present invention to use electrical communication such as a wire running with the hose as shown in U.S. Pat. No. 5,044,445). However, this method suffers from the danger of a broken wire in a harsh hose environment and requires somehow attaching a wire to the hose.
A single channel or multiple RF radio channels can be used with the present invention. While the invention will work with one channel, it is desirable to have two or more channels to achieve diversity. Diversity increases the system's resistance to fading. Fading occurs with a single radio channel when the radio-wave travels from the transmitter to the receiver by more than one path (multi-path reception). In this case, the radio signal can reflect from objects resulting in a reflected wave and a direct wave (or two reflected waves) arriving at the receiver at different times. In some cases, the time difference is sufficient to create an approximately 180 degree phase shift between the two signals This causes a total cancellation of the signal. This is known as a deep fade.
Diversity communication uses at least two separate transmitting or receiving antenna locations or different frequencies to minimize this fade problem. It is within the scope of the present invention to use any type of diversity method or none at all. The preferred method is to transmit simultaneously on two different radio channels (i.e., separated in frequency). This type of diversity causes fading to occur at different physical locations for each channel. Thus, if one channel is faded, there is a high probability that the other is not. The method of having multiple receiving antennas is also possible. For example, a fire vehicle could have two receiving antennas (say one on the front of the truck or top of the cab and one on the rear of the truck). This type of diversity (also known as space diversity) accomplishes the same result (makes the system more immune to fading as the transmitter moves around).
At the fire engine or other pump location, at least one radio receiver 3 receives signals from the nozzle transmitter 2. An optional controller 4 can drive a display 5 that shows that pressure visually, and can optionally control a proportioning valve 8 automatically. The proportioning valve 8 normally controls the flow of water into a hose 6. An alternate method (not shown) is to have a microcontroller 4 directly control the throttle of the fire truck pump 7. It should be understood that any method of controlling the pump, or displaying the nozzle or hose pressure, is within the scope of the present invention. An additional, optional flow meter 9 can report the flow rate to the processor 4. The processor 4 can also optionally measure pressure at the pump discharge. The controller 4 can be any processor including a microcontroller, microprocessor, PC or any other type of computer or processor.
There are some fire engine manufacturers who use a system called a “pressure governor.” This system monitors the water pressure at the main pump discharge on the fire engine. Once a target pressure is set by the operator, the pressure governor will increase or decrease the engine speed to maintain the target pressure. The present invention can improve that system by providing the actual pressure at the nozzle instead of the pressure at the main pump discharge. Without actual knowledge of nozzle pressure, friction loss can cause errors in a pressure governor system. If the nozzle person changes (increases) the water flow setting on the nozzle, more water tends to flow, reducing the pressure at the pump discharge. The pressure governor tries to correct this pressure, but the actual water flow at the nozzle will be incorrect because the increased water flow also increases the friction loss provided by the hose, and this factor is not taken into account by the pressure governor because of its pressure monitoring location. With actual nozzle pressure information, this problem is eliminated no matter what the instantaneous hose friction loss is.
The present invention is particularly useful during the first critical minutes upon arrival at a fire scene. The pump operator is extremely busy establishing a proper water supply to the firefighters at the nozzle of the initial attack hose line(s). During these critical minutes, the driver must 1) put the fire engine into pump gear; 2) chock the wheels, 3) open the tank-to-pump gate, 4) throttle up to develop pressure at the pump discharge, 5) re-circulate water to prevent the pump from overheating, 6) open the gate (valve) to the attack line(s), 7) open the discharge gate to get water to the nozzle, 8) set the over-pressure relief valve, 9) coordinate setting up a continuous water supply (e.g., fire hydrant, second-due fire engine) to the fire engine, 10) bleed the air from the continuous supply line, 11) transition the pump water inlet from the truck tank to the intake by gating both sources simultaneously (i.e., close one while opening the other), 12) fill the tank with the continuous water supply, and 13) if more than one attack line is used, monitor the discharge pressure gauges to gate the discharge as nozzles are opened and closed.
The pump operator must also monitor the radio to ascertain if any attack line is having pressure problems and try to adjust the gating or pump accordingly. The present invention can help in these critical minutes by providing real-time reporting of pressure at the attack end of each of the hoses. In this early stage, the entire operation can remain manual. After the flow becomes steady to each attack line, the pump operator can switch that line to the automatic mode of the present invention so that nozzle pressure is maintained automatically. This frees up the operator to attend to the other essential tasks such as coordinating a continuous water supply.
As previously stated, the present invention can optionally have a two-way communications radio also incorporated into the nozzle unit to provide easy communication between the nozzle person and the pump operator. A push-to-talk (PTT) button 13 (shown in
Also as stated before, an additional pressure sensor can be added at the pump discharge so that kinks and leaks on the hose can be quickly assessed. This can be accomplished by comparing the differential pressure between the pump discharge and the nozzle, taking into account the friction loss of the hose. If there is a kink in the hose, the differential pressure will be higher than normal taking into account the expected pressure loss along the hose due to friction loss. The processor can automatically calculate the expected differential pressure and determine if there is a kink in the hose, and generate and alarm or take other action.
It should be particularly noted that the present invention can be used with multiple nozzles and multiple firefighters. In the case of multiple nozzles, the processor is particularly useful in monitoring and/or controlling the pressure and flow at each nozzle independently.
It should also be noted that the present invention can be used in a much wider context than just that of fire hose pressure sensing. Any number or type of sensor can be mounted at the remote end of the hose or on or in the nozzle. Examples of these diverse sensors 10 could include toxic gas sensors, heat or temperature sensors and a video camera. Any sensor that can be mounted on or in proximity to the nozzle is within the scope of the present invention.
The present invention has been described by various written descriptions and illustrations. It will be recognized by one of skill in the art that numerous changes and variations are possible. All of these changes and variations are within the scope of the present invention.
The present invention is related to and claims priority from U.S. provisional patent application 60/518,157 filed Nov. 7, 2003. Application Ser. No. 60/518,157 is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60518157 | Nov 2003 | US |
