Patent Application
20240024719
This invention is directed to an improved method of connecting fire notification devices to a fire sprinkler system, with a self-generating power source to increase reliability in a variety of building life-safety applications.
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The automatic fire sprinkler system was patented by Philip W. Pratt of Abington, Massachusetts, in 1872. This was followed by the automatic electric fire alarm system patented in 1890 by Francis Bobbins Upton, an associate of Thomas Edison. And over the years the fire protection trade has grown at an exponential rate since the above technologies were first introduced, giving way to new innovations that have radically improved the life-safety industry, with national codes and regulations keeping pace.
A modern home fire sprinkler system is designed to contain and extinguish a fire at or near its origin. However, by itself, it does not alert the household of the emergency situation and requires additional notification equipment for the occupants. The most common types of notification equipment are an exterior riser bell, a standalone smoke alarm, and a fire alarm system.
While an exterior riser bell may draw the attention of anyone outside their homes; it does very little for those inside the house. The sound from an outside bell is attenuated by the walls and drowned out by any interior ambient noise. Also, it is known that most sleeping children, especially those with a hearing impairment, will not awaken to the high frequency pitch of a smoke alarm. Adults under the influence of any substances have similar difficulty. This reduces the amount of time needed to safely evacuate.
Fire alarm systems on the other hand are designed to detect the early signs of a fire and then alert the occupants of the building to evacuate. A fire alarm system can even dispatch the local fire department to that location. Therefore, both a fire extinguishing system and an alarm system are undeniably essential. Such systems are required by code in most jurisdictions and their design depends on building structure and occupancy. Combining these two systems through a sprinkler waterflow detection switch reduces the loss of life and property damage. However, both systems do have their inherent strengths and weaknesses.
Automatic Fire Sprinkler Pros: They are proven to be more reliable and effective than the delayed response of the local fire department. Most fires are extinguished by the time they arrive on-site. Property damage and environmental impact is substantially lower with fire sprinkler systems, especially compared to a fire department's aggressive methods to put out a fire. Fortunately, a fire sprinkler system can operate independently, without the need of an external power source.
Automatic Fire Sprinkler Cons: As a standalone system it cannot alert anyone that it has been actuated. Notification requires the use of one or more of the following: a water motor gong, an electrified waterflow switch combined with a local exterior riser bell, and a fire alarm system with interior and exterior notification devices. Once the sprinkler system releases water, it will continue to flow until stopped manually by a human closing a valve. In this design, any form of notification is beneficial in reducing further water damage once the fire has been extinguished. Also, a broken sprinkler head/pipe may continue unnoticed for some time.
Waterflow Switch Pros: The most common and least expensive method to interface a fire alarm panel with a sprinkler system is to use a vane or pressure waterflow switch. It has an adjustable means to delay the output up to 90 seconds which prevents water pressure fluctuations from triggering a false alarm.
Waterflow Switch Cons: The waterflow switch is strictly a component and not a standalone device. It requires additional equipment, such as a riser bell and/or a fire alarm system to have any fire life-safety value. The waterflow switch commonly utilizes a pneumatic time delay mechanism which is known to have one of the highest failure rates in fire sprinkler systems. This is due to the wear and tear of its pneumatic damper and exposure to the elements. These difficulties result in sporadic false alarms. Consequently, this requires the entire waterflow switch to be exchanged for a new one since replacement parts are not readily available. This is an expensive repair as it typically requires participation of both the fire sprinkler and alarm technicians.
There are two types of bells on the market, the electromechanical and the water motor gong (WMG). The electromechanical is the most common and is usually powered directly by a 120 VAC source and is mounted to the exterior of the building. The WMG is completely mechanical, operating on the principle of flowing water rapidly spinning a turbine that rotates a striker, which in turn clangs against the gong. This eliminates the need for an external power source which makes it fail-safe in areas with unreliable utility service. Alternately, an electric bell is used which comes in lower voltage ratings and can be wired directly to a lower voltage source from a typical fire alarm system.
Fire Alarm Systems based on smoke or heat are designed to detect the early signs of a fire, alerting the building occupants to evacuate. They can also communicate with an off-site monitoring station, which then dispatches the local fire department to that location. An early warning may also be enough time for someone on-site to evaluate and extinguish the fire prior to the local fire department arriving.
However, on its own, this kind of fire alarm system is not designed to alert anyone that a sprinkler head has been actuated. It requires the use of a separate waterflow switch to trigger an alarm. It also requires a dedicated 120 VAC power source and backup batteries, with associated peripheral devices installed per fire code. And depending on the type of installation, periodic inspections are required, increasing the overall operating costs.
The last and most recognized form of life-safety equipment is the standalone smoke alarm found in most private homes, apartments, and hotels. It is a self-contained device with the smoke sensor, sound tone generator, and optional strobe light being integral parts of the unit. Although similar to the smoke detector found in most commercial and industrial environments, this device is not interchangeable. A smoke detector is a smoke sensor only, relying on a central fire alarm panel to control and power the notification appliances, such as horns, strobes, and low frequency sounders. Smoke alarms come in many designs, and as with most things, have their pros and cons.
Standalone Smoke Alarm Pros: For the homeowner this device is the least expensive option when compared to a complete fire alarm installation. They can be hardwired to a standard 120 volt household circuit; with an integral backup battery should the main power fail. Others are powered from a battery alone. Modern devices even allow multiple smoke alarms to be linked through a pair of wires or wirelessly, causing all alarms to sound throughout the home at the same time when one of them senses smoke. And depending on the technology used to sense smoke particles, the device typically detects smoke presence before the temperature increases and triggers the sprinkler head. It is a very cost-effective early warning system.
Standalone Smoke Alarm Cons: These devices do not have the reliability of a commercial grade smoke detector tied to a fire alarm system. A 120 volt device with a failed battery backup is inoperable during power outages or a circuit breaker trip. And the functionality of a device that is powered from a battery alone is questionable should the battery expire before replacing it. They are notorious for false alarms, and relentlessly chirp when the battery is low. This can frustrate a homeowner to the point of permanently disabling the device, making them useless.
Further, years of laboratory testing have proven that the typical smoke alarm tone of about 3 kilohertz will not awaken most children, those with diminished hearing, or adults under the influence of any substances. Whereas a low frequency tone of 520 hertz will. However, due to the higher power requirements and enlarged physical size of the low frequency generator, currently available smoke alarms do not produce the 520 hertz tone output.
In order to use the more effectual low frequency sounders, a complete fire alarm system needs to be installed. Unfortunately, most homeowners opt out due to its high cost and maintenance requirements. What is needed is a simple and effective way to sound an alarm by a high reliability device that avoids the difficulty and frustrations of current art devices and arrangements.
The conceived invention simplifies current art methods of fire sprinkler systems by replacing vane and pressure type of waterflow switches with a single water driven hydroelectric flow switch generator having dual functionality. It includes power generation and fire alarm system activation when water moves through a sprinkler system. The system also includes a digital controller to drive at least one notification appliance device which sounds an alarm. The alarms comprise an exterior riser bell, low frequency sounders, horns and flashing strobes.
Another embodiment of the invention works with both current fire sprinkler and fire alarm systems. It includes both alarm and circuit supervisory functions to enhance the operation and maintenance of these systems.
The embodied invention is conceived to be useful in private one and two family homes, multifamily apartment complexes, and commercial or industrial buildings. The invention works with the operation of fire sprinkler systems. In a sprinkler system, water is held under pressure within dedicated pipes and prevented from flowing out by the sprinkler heads. When a fire raises the temperature to the triggering point, the sprinkler head nearest to the flames bursts open and releases the water to extinguish the fire.
The conceived invention utilizes an HFS and can be adapted to various types of commercial/industrial fire sprinkler configurations. However, it is ideally suited for one and two family homes. The HFS gives the homeowner an option of installing low frequency sounders in each of the sleeping areas, without the major expense of having to install a complete fire alarm system. This technology increases the life-safety effectiveness of the home sprinkler system a magnitude several times over one that solely relies on an exterior bell and/or standalone smoke alarms, saving lives, resources, and money. The Hydroelectric Flow Switch operates completely off the grid with clean renewable energy, consumes absolutely no power while in its standby mode, and functions with zero emissions. The HFS is virtually maintenance free, with no backup batteries to maintain or replace, and is not affected by utility power surges and outages.
The instant a sprinkler head is triggered, the HFS taps into the kinetic energy of the water moving through the fire sprinkler riser and self-generates enough electricity to power its own electronic time delay circuitry and any of the notification appliances connected to its notification appliance circuit output.
The HFS can be constructed from any suitable material, such as plastic and/or metal. The device can be designed as a single unit with the generator, the electronic circuitry, and all associated components housed within the same enclosure. Or in a preferred embodiment, the device is designed as a modular system with the generator and turbine in one enclosure, and the electronic control circuitry in another enclosure. A two part modular design allows the two to be linked through a cable harness. The generator can be designed to output a direct or preferably an alternating current. The turbine can be designed with different blade styles such as straight, curved, or concave.
In
When the temperature around an individual sprinkler is high enough to break the bulb, it separately activates as illustrated by open sprinkler head 106a and closed sprinkler head 106b respectively. When the bulb breaks, water sprays over the flames in that area. Spraying water flows through the sprinkler riser and through the hydroelectric generator 104. The generator creates electrical power (AC or DC), and the exit water continues on to the sprinkler distribution pipe 117. The electrical power output of the generator 104 is connected to the HFS control module 112 where the power is regulated to the proper voltage level for a digital microcontroller, and immediately starts the delay timer sequence. The delay timer is needed to prevent false alarms from water pressure surges and other reasons. The delay is adjustable from 0 to 90 seconds, and typically set between 30 to 60 seconds.
At the end of this delay timer sequence, the module 112 notification appliance circuit (NAC) output turns on all alarm notification devices: strobe 113, low frequency sounder 114, and alarm bell 115, without the need of any external power supply. The generator 104 is designed to supply all the power needed for the module 112 and notification devices 113, 114, and 115 regardless of the number of sprinklers activated. Optionally, a separate smoke alarm 116 is installed for redundancy, and is usually needed depending on local fire codes.
An inspector's test valve 119 is installed downstream from the generator and can be turned on for inspection, testing, and troubleshooting. The water flow is sent to a drain. The designed water flow through the valve is equivalent to the amount of flow through the smallest sprinkler head on the system when activated.
The ability to power the fire alarm notification devices separately from other electrical power sources is a distinct advantage of the embodied invention. In some cases, a fire causes the external electrical power to be shut off, and battery backup systems may fail. Also, the embodied invention replaces the vane waterflow switch which is known to be unreliable.
In
The converter 154 rectifies the AC power to DC and a separate voltage regulator 153 controls the DC voltage to a constant amount for the digital microcontroller and an internal delay timer 157. Typically, the voltage is set to microcontroller requirements to avoid additional voltage regulation devices.
The internal delay timer 157 is immediately started when power is applied to the digital microcontroller. A timer setpoint 155 is used to avoid nuisance alarms and is typically set at a value of 30-60 seconds. When the timer reaches zero, and power is still being supplied by the generator, an alarm relay 158 is activated and sends a voltage to the NAC output 159. The alarm notification devices 113, 114, 115 are then activated concurrently. The operating voltage range for a typical 24 VDC rated notification appliance is 16 to 33 volts DC. This allows the notification appliances to utilize the unregulated DC voltage directly from the AC to DC converter. Using unregulated DC voltage means that there is no separate voltage control circuit added to the generator, nor is there voltage regulation included in the generator.
An overcurrent module 156 protects the HFS control module 112 and generator 151 from damage, due to excessive current drawn in the event of a short circuit across the NAC output. It also assures that the waterflow switch continues to function properly and will still trigger an external fire alarm system, if one is being used, even though the NAC output has been disconnected from its HFS generator power source.
In
The generator 151 is designed so that the power needed for the digital microcontroller and the alarm notification devices can be provided by a single activated sprinkler head.
The sprinkler system riser 201 is connected to the building water line (not shown) and is typically fed from a city water supply. The water supply feeds the fire sprinkler riser 201 and the connected sprinkler distribution pipe 218 with water pressure. The water is prevented from spraying out any of the sprinkler heads 205a,b until a liquid filled glass bulb breaks from the heat of a flame.
When an individual sprinkler bulb breaks, it activates a sprinkler head 205a but not neighboring sprinkler head 205b. The actuated sprinkler head causes water to flow through the sprinkler riser 201 and through a tamper butterfly valve 202. The tamper valve has an electrical contact that closes and notifies the fire alarm system 210 if the valve has been closed. The fire alarm system then notifies maintenance/security of a system fault due to the closed supply valve. This prevents unauthorized individuals from tampering with the valve, hence its name.
The riser 201 is monitored by the fire alarm system 210 through the HFS control module 211. In its standby state the city water supply fills the riser 201 on both sides of the normally closed alarm check valve 203 and distribution pipe 218 with water under pressure. The water is prevented from flowing until one or more of the heads are triggered by enough heat from a fire, as shown by closed sprinkler head 205b and open sprinkler head 205a respectively. When sprinkler head 205a triggers and starts spraying water over the flames, water flows up through the riser 201 and into alarm check valve 203 where it forces an internal valve to open up a small water pathway to the HFS generator 217, with the majority of the water feeding the distribution pipe 218. This is accomplished by the internal mechanical motion of the check valve. Alarm check valves that provide this function are commercially available.
The small amount of water flows through the hydroelectric generator 217 where it spins a water based turbine that generates an alternating current, before exiting through the drain pipe. The output power of the hydroelectric generator 217 is connected to the input of the HFS module 211 where the power is conditioned and regulated to the proper voltage level to energize the microcontroller, which in turn starts a delay timer. Again, the delay is typically 30-60 seconds. At the end of the delay, and the generator still creating power, the waterflow switch and NAC output circuit of module 211 activate. This triggers the alarm system 210 and an associated bell 212 respectively. The fire control system 210 then powers the strobe 213, and horn 214, and other devices as designed.
The HFS generator and control module replaces several of the unreliable water based mechanical components, such as a retard chamber, pressure waterflow switch, water driven motor gong, and associated piping, resulting in a substantial savings.
Smoke detector 215 activates during a fire and sends an alarm signal to the fire control system 210. The fire control system is powered by an electrical circuit breaker panel 200.
The
In
The power is preferably unregulated DC power directly from the AC-DC converter 312 for circuit efficiency. Alternately, this can be regulated if the NAC appliances require a specific DC voltage for activation.
Water stops flowing through the sprinkler riser conduit. The HFS generator stops generating power.
The flow switch 317 is a unique and special design. It is monitored by the fire alarm system 305a,b,c for three types of outputs. The normal case is to look for the value of the resistor 304 in the circuit. This means the circuit and all devices are connected properly. The second is a contact closure, meaning that there is a fire. Lastly, an open circuit will indicate that there is a problem with the circuit, and maintenance is required to troubleshoot the problem.
If the waterflow switch 317 and NAC supervision 319 fire alarm monitoring points are not monitored, circuit supervision cannot be achieved. Fault conditions will go unnoticed.
This unsatisfactory result can be avoided with the addition of an end of line resistor 321 and a monitoring point from a 3rd party fire alarm system.
The NAC EOLR 321 is a special inclusion into the operation of the HFS. If included, the supervision of the NAC field wiring, and subsequently all of the notification devices that are attached to this circuit, is accomplished with the addition of a monitoring point from a 3rd party fire alarm system.
The HFS control module has three associated NAC I/O positions:
The notification appliance circuit wiring connects to the NAC output and extends outward to the field, following a path through each location in the building where the notification devices are mounted, attaching to each device via its terminal screws, and then terminating at the last device with an appropriate valued end of line resistor across its same terminals. This EOLR is what the monitoring point senses, showing a normal condition on the fire alarm system. However, should the wire break or become disconnected from under the terminal screw, the monitoring point can no longer see this resistor, and consequently triggers an open circuit fault condition on the fire alarm system.
It should also be noted that if the wires have a short across them, or become grounded, the monitoring point will annunciate these fault conditions as well. The HFS control module has an internal NAC supervision circuit that connects the NAC output field wiring to the NAC supervision monitoring point (when in a non-fire standby state), via an delectromagnetic relay in reverse polarity. This blocks all of the monitoring point's current from passing through the polarized (diode protected) notification devices, forcing the current to flow exclusively through the EOLR, thereby preventing a false short circuit fault condition. Once the module is triggered due to a fire, and before the timer has completed the countdown, the internal NAC supervision relay removes the NAC output field wiring and its EOLR from the supervision monitoring point. Simultaneously, the equivalent EOLR is placed across the NAC supervision monitoring point output to prevent a false open circuit fault condition. The equivalent EOLR must match the resistor value that is connected to the last device out in the field. Therefore, the only reason for the equivalent EOLR is to satisfy the NAC supervision circuit and keep the fire alarm system clear of any false open circuit conditions whenever the HFS has been triggered due to a fire.
In general, the digital controller electronically controls when the alarm relay, and supervision relay when used, energizes and changes state. For example: a) if only an alarm relay is used, as shown in the bare bones home configuration, the alarm relay would be energized and change state at the end of the timer countdown; and b) when using both an alarm and supervision relay, as shown in the commercial configuration, the supervision relay would change state at any time before the alarm relay, to prevent power from the HFS generator back feeding into the NAC supervision monitoring point, and causing possible damage to the 3rd party fire alarm system. And through proprietary code commands, i.e. programming, the digital controller starts its timer and relay output sequence as soon as the HFS control module is powered up via the HFS generator; then resets automatically and de-energizes the relay(s) as soon as the HFS generator stops providing power due to the sprinkler control valve being closed and water no longer flowing through the sprinkler riser.
Embodiments of the present invention utilize a digital controller or a microcontroller device which includes a microprocessor, programmable memory components, programmable analog and digital blocks, and volatile or non-volatile memory. A microcontroller contains one or more processor cores along with memory and programmable input/output peripherals. Program memory is usually included on chip, as well as RAM. Microcontrollers are primarily designed for embedded applications, but also provide for general purpose applications and functions. Various microcontrollers have differing features, including different capacities, and are often purpose built or selected from a wide variety of available designs.
While various embodiments of the present invention have been described, the invention may be modified and adapted to various operational methods to those skilled in the art. Therefore, this invention is not limited to the description and figures shown herein, and includes all such embodiments, changes, and modifications that are encompassed by the scope of the claims.
