CA2259346C

CA2259346C - Mine fire and emergency warning stench injector

Info

Publication number: CA2259346C
Application number: CA 2259346
Authority: CA
Inventors: Wayne William Kitching
Original assignee: ZACON Ltd
Current assignee: ZACON Ltd
Priority date: 1999-01-15
Filing date: 1999-01-15
Publication date: 2008-12-09
Anticipated expiration: 2019-01-15
Also published as: CA2259346A1

Abstract

A mine fire and emergency warning device for the protection of personnel working underground. The device will inject a (rotten egg) stench into fans blowing fresh air to workers underground, as well as into compressed air systems used to operate drilling equipment underground. The automated device disperses the stench at a metered rate, and simultaneously to a multitude of sites, which may be kilometres apart.

Description

Title: MINE FIRE AND EMERGENCY WARNING STENCH INJECTOR

[001] This mine fire and emergency device relates generally to the monitoring and control of underground mine warning systems.
BACKGROUND AND SUMMARY

[002] In mine workings underground; situations arise which warrant the immediate notification and attention of workers underground.
Typical of warning situations would be: fire in any area underground; dangerous blasting conditions, rock shifts and bursts, cave-ins and even power failures.

[003] To do this an ethyl mercaptan (rotten egg) smell is injected into mine ventilation air and compressor systems. This smell is purposely objectionable and attention getting.

[004] Accordingly it is an object of the present invention to provide a new and improved device which will provide users a failsafe manner of injection even with power failures; as a manual back-up override is provided.

[005] Another object of the present invention is to provide a device that can be fired immediately and simultaneously from a central station, even if injection points (i.e the remote-stations) are kilometres apart.

[006] Another object of the present invention is to provide a device that has no small orifices, screens or restrictions to plug.

[007] Another object of the present invention is to provide a device that injects stench at a metered rate (and thus meets = CA 02259346 2006-09-13 governmental standards) under various air flows in both ventilation and compressed air applications.

[008] Another object of the present invention is to provide a device that has continuous feedback to the central-station giving the status of the remote-stations under normal as well as firing conditions.

[009] Another object of the present invention is to provide a complete operational system with as few moving parts as possible to provide minimal maintenance.

[0010] Another object of the present invention is to be able to reload the system easily and quickly; so the device is ready to fire again should the need arise.

[0011] Another object of the present invention is the ability of the apparatus to house and fire a single or a multitude of stench cylinders (reservoirs) (for applications having large air volumes).
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0012] By way of further explanation, exemplary apparatuses will now be described with reference to the accompanying drawings, in which:
Fig 1 is a pictorial view of a central-station, showing some of the components thereat.
Fig 2 is a similar view of one of plural remote-stations.
Fig 3 shows a circuit diagram as it relates to the central-station.
Fig 4 shows the circuit diagram as it relates to tow of the remote-stations.

[0013] The apparatus 20 shown in the accompanying drawings and II~
~III

= CA 02259346 2006-09-13 described below is an example. It should be noted that the scope of the patent protection sought is defined by the accompanying claims, and not necessarily by specific features of exemplary embodiments.

[0014] When an emergency situation arises, a call is placed to a constantly-manned emergency number located at a central-station 23.
This may be a control room, shift office, security gate or hoist operator station. At these sites there may be a computer console or a small control panel. An individual at the central-station will activate the stench warning system. When workers smell the injected stench, they depart immediately to a refuge station. At this refuge station all individuals are accounted for and the entrance door is sealed until notification that the emergency situation is passed and under control.

[0015] At the central-station 23, indicators 25 indicate stench injector pressures (in the remote-stations 27) at all times. Two alarm indicators are also present. These are: a "stench system charged" alarm 29 (which goes off when the stench pressure in the stench reservoir or cylinder 30 (at each remote station 27) drops below the pressure required for full evacuation of the cylinder into the compressed air line or ventilation air conduit 32; and a "stench system discharged" alarm 34, which comes on when the full contents of the stench cylinder 30 (at each remote-station) have been discharged into the compressor or ventilation conduits 32.

[0016] Another indicating light at the central-station 23 is a "power on" light 36 which will go out upon a loss of power supply in the remote-stations 27. If that happens, an. operator at that remote-station opens the injector enclosure, and opens a manual-bypass valve 38, to inject the stench into the conduit 32.

[0017] A multitude of the remote-stations 27 can be fired simultaneously by the operation of a single activation switch 40 at the central-station 23. 24VDC switching and indication over telephone lines allows for control of many remote-stations 27, which may be kilometres apart and away from the central-station 23. By this method, central control of all release areas can be provided.
The lines for carrying the activation-signals are connected between the terminals AS on each remote-station and on the central-station.

[0018] The remote-station 27 is designed as follows (referring to Figs 2,4). Single or multiple stench reservoirs in the form of cylinders 30 (held by clamping brackets) feed through stainless steel, PTFE-lined, hose to a manifold 41. The manifold 41 also holds the pressure transmitter 43 which sends the pressure signal to the central-station 23. The pressure-signal is sent to the central-station along lines connected between the terminals PS-1, PS-a, etc on the remote-stations, and the corresponding terminals on the central-station. Also at the remote-station in Fig 2 is a local pressure gauge 45, the manual-bypass valve 38, a vent-to-atmosphere valve 47 (used when replacing cylinders), and connections to a metering valve 49.

[0019] The metering valve 49 at each remote-station includes an electric actuated ball-valve operated by a repeat cycle timer 50, which has individual "open" and "closed" time settings. This is the only moving portion of the complete system. As the ball-valve opens it reveals a large opening (preventing plug-ups), then closes again.
This sequence is repeated over and over until all stench has been discharged.

[0020] The "open" and "closed" times in the cycling relay 50 are adjusted in a timed sequence to provide proper underground exposure according to either the compressor or ventilation SCFM
(standard cubic feet per minute) of air flow. The National Institute for Occupational Safety and Health through the American Conference of Governmental and Industrial Hygienists have selected a STEL (Short = CA 02259346 2006-09-13 Term Exposure Limit) for stench applications (ethyl mercaptan) to be 2 ppm (parts per million) in the U.S.A. and 1.5 ppm in Canada.

[0021] In an emergency, when it is necessary to inject stench, the following is performed (assuming the reservoir cylinder 30 at the remote-station starts off at full pressure, and the "stench-charged"
indicator 29 at the central-station is on). Now, the operator at the central-station 23 presses the timed latching switch 40 that signals all the remote-stations 27 to make stench. As the stench-agent is discharged, the pressure in the stench reservoir 30 will slowly fall, and after a few moments the "stench-charged" indicator light 29 will go off. Then, after four to seven minutes from the start of the injection cycle, the pressure in the stench-reservoir 30 falls so low that the "stench-discharged" light 34 will illuminate, indicating that all, or nearly all, the stench-agent has been injected into the ventilation or compressor conduits 32. After ten minutes, the switch 40 at the central-station 23 unlatches, thereby signalling the metering-valves 49 in the remote-stations to stop cycling, and to remain closed.

[0022] The remote-stations will stay in this closed position indefinitely until they are recharged. To return the system to "stand by" for recharging, the operator turns the "activate-stench" switch 40 at the central-station 23 to the "OFF"
position.

[0023] In the central-station 23, as shown in Figs 1,3, the "power on" light 36 on the panel indicates power is present in the remote-stations. The central-station includes pressure indicators 25 (which may be separate indicators, one for each remote-station, or may be a single indicator instrument which registers the respective readings from the remote-stations in sequence). The indicator 25 at the central-station receives = CA 02259346 2006-09-13 signals from the pressure transmitters 43 at the remote-stations.
The central-station also has the alarm settings for "stench-charged" and "stench-discharged" warning lights 29,34, which again indicate pressure conditions in the stench-reservoirs in the respective remote-stations 27.

[0024] The "stench system charged" light 29 in the central-station 23 comes on when the stench-reservoir 30 in the remote-station 27 has enough pressure to fully inject the contents of the reservoir or cylinder 30 into the ventilation or compressor conduit 32. The "stench discharged" light 34 in the central-station comes on when, after a discharge of stench-agent at the remote-station, the stench-cylinder 30 has fully discharged into the ventilation or compressor conduit 32.

[0025] The signalling system between the remote-stations 27 and the central-station 23 operates on 24DC supply, and a check is kept at the central-station that power is present at the remote-stations, as necessary for transmittal of the injector pressure signal from the remote-station to the central-station, as well for receipt of the stench activate signal from the central-station to the remote-stations.

[0026] The timer-delay relay TDE at the central-station switches off the stench activate signal, and thereby shuts down the injection system in the remote-stations, ten minutes after its initiation. By this time all of the stench-agent has been injected. The shut-down prevents unnecessary cycling of the metering valve 49.

[0027] The master activation switch 40 at the central-station 23 controls the release of stench agent at the remote stations 27.

This switch has a lockable hinged cover over it to prevent accidental firing of the stench system. Placing the switch 40 in the "ON" position begins the injection cycle. Placing the switch in the "OFF" position terminates injection immediately.

[0028] The remote-stations, as shown in Fig 2 and Fig 4, serve to inject stench-agent stored at the remote-stations into either the compressed air or ventilation conduits 32, as required. (In Fig 4, which shows two of the remote-stations, the component numerals have been given suffixes, which indicate remote-station number one and remote-station number two. It will be understood that an installation in a typical mine might have e.g six remote-stations.) The remote-stations include the following components and functions. The activation-relay AR-1 (at remote-station number one) accepts the activate signal from the central-station, to start the stench inject cycle at the remote-station. The cycle timer relay 50 has independently variable "open" and "closed" time cycles which operate the local metering valve 49 through local "open" and "close" relays. These relays drive the metering valve "open" and "closed" respectively, and are time dependent on the local cycle time settings. These relays also prevent inductive kick-back generated when the metering valve 49 suddenly and continuously reverses directions.

[0029] In the remote-stations, the metering-valve 49 is normally closed. When the stench inject sequence begins, this valve cycles continuously from closed to open to closed etc. The amount of time the valve is open or closed is set to produce the SCFM (Standard Cubit Feet per Minute) in the airstream that the stench system is asked to inject into.

[0030] The power-relay PR-1 in the remote-station-1 is energized when the remote-station power is "ON". If there is a power failure at the remote-station, power-relay PR-1 interrupts the injector pressure transmitter signal going to the panel indicator 25 at the central-station 23. Thus, this indicator will show an "ERROR" (interpreted to mean "loss of injector power", which is indicated by lamp 36 at the central-station). The injector pressure transmitter 43 sends the pressure signal from the remote-station to the central-station at all times, provided the power is "ON".

[0031] A 70w heater H is used to heat the remote-station enclosure when ambient conditions drop below freezing. This provides protection for the solid state equipment inside the enclosure. As well, the heater helps maintain pressure in the stench cylinder in below-freezing conditions.

Claims

Claim 1. Stench warning apparatus, wherein:
[2] the apparatus includes a central-station and plural remote-stations;
[3] each remote-station includes, respectively:-[4] - an airstream-conduit, for conveying an airstream;
[5] - a stench-reservoir, for storing a supply of a stench-agent;
[6] - a stench-conduit, for conveying the stench-agent from the stench-reservoir into the airstream-conduit;
[7] - a stench-conduit-valve, which is changeable between a closed condition and an open condition;
[8] - in the open condition of the stench-conduit-valve, the stench-conduit remains open to the conveyance of stench-agent from the stench-reservoir through the stench-conduit to the airstream-conduit;
[9] - in the closed condition of the stench-conduit-valve, the stench-conduit remains closed to the conveyance of stench-agent from the stench-reservoir through the stench-conduit to the airstream-conduit;
[10] - a stench-conduit-valve-operator, which is operable responsively to the remote-station's receiving a stench-actuation-signal;
[11] - a differential-pressure-sensor, for sensing what pressure-differential is available to propel the stench-agent from the stench-reservoir, through the stench-conduit, into the airstream; and [12] - a pressure-signal-transmitter, for transmitting a pressure-signal indicative of the said pressure-differential to the central-station;
[13] the central-station includes:-[14] - a stench-actuation-signal-transmitter, for transmitting a stench-actuation-signal to the plural remote-stations;
[15] - a pressure-signal-receiver, for receiving the pressure-signals from the respective remote-stations;
[16] - an activatable pressure-differential-alerter, which is effective, when activated, to provide an alert indicative of a magnitude, or range of magnitudes, of the said pressure-differential;
[17] - a pressure-differential-alerter-activator, for activating the pressure-differential-alerter responsively to the pressure-signal received from one of the remote-stations signalling that the magnitude of the pressure-differential of that remote-station is outside a predetermined effective range.
Claim 2. As in claim 1, further characterised in that:
[2] the apparatus includes an activatable reservoir-charged indicator, which is able to indicate a reservoir-charged condition differently from a reservoir-not-charged condition;
[3] the reservoir-charged condition is a condition in which the magnitude of the said pressure-differential exceeds a predetermined level above which the reservoir is pressurised sufficiently to inject an effective amount of stench-agent into the airstream conduit;
[4] the reservoir-not-charged condition is a condition in which the pressure-differential is below the said predetermined level.
Claim 3. As in claim 1, further characterised in that:
[2] the apparatus includes an activatable reservoir-discharged indicator, which is able to indicate a reservoir-discharged condition differently from a reservoir-not-discharged condition;
[3] the reservoir-discharged condition is a condition in which the magnitude of the said pressure-differential is below a predetermined level below which the reservoir is pressurised insufficiently to inject substantially no, or no further, amount of stench-agent into the airstream conduit;
[4] the reservoir-not-discharged condition is a condition in which the pressure-differential is above the said predetermined level.
Claim 4. As in claim 1, further characterised in that the central-station is so structured the pressure-differential-warning, when activated, indicates which one of the plural remote-stations has transmitted the pressure-signal signalling that the pressure-differential is below a pre-determined level of effectiveness.