MXPA97001440A - Smoke detector, integral and self-adjustment, and method to make my operation - Google Patents

Abstract

A smoke detector, integral and self-adjusting, comprising: a smoke sensitive element, operable to produce a sensitive element signal, indicative of a smoke level, in a space or region; an operable alarm control circuit to determine successive flotation settings with the use of the signal of the sensitive element produced during the corresponding successive intervals of data acquisition time, extending each time interval of obtaining data, a duration of obtaining data, each adjustment of floating indicative, at least in part, of relationships between the signal of the sensitive element in the corresponding data acquisition time interval and a clean air signal produced through the sensitive element in clean air. the alarm control circuit can also be operated with the use of an alarm threshold, the signal of the sensitive element and the corresponding one of the successive float settings to determine in successive determination times of the smoke level, if the signal of the sensitive element indicates an excessive level of smoke in the region, the corresponding one of the flotation settings having as its corresponding time interval of obtaining data, one that is sufficiently recent with respect to the corresponding time of determination of smoke level that the signal of the sensitive element in absence of smoke is not likely to have changed significantly from the data collection time interval to that smoke level determination time, the alarm control circuit also operable with the use of an excessive smoke level determination, to indicate the existence of an alarm situation, and a discreet accommodation that is on the elemen to sensitive and the alarm control circuit and which operatively couples with the sensitive element towards the region of the space

Description

SMOKE DETECTOR, INTEGRAL AND SELF-ADJUSTMENT, AND METHOD TO OPERATE THE SAME.

Technical Field The present invention relates to smoke detectors and, in particular, to an integral smoke detector having internal self-adjusting characteristics that enable it to compensate for its sensitivity to smoke increase or decrease.

BACKGROUND OF THE INVENTION A photoelectric, point, smoke detector measures smoke conditions at a location within a region or space and produces an alarm signal in response to the presence of highly unacceptable smoke levels. Such a system contains in a discreet housing covered by a canopy of -take for smoke, a device that emits light ("emitter") for example, an LED (for its acronym in English) and a light sensor ("sensor"), for example a photodiode placed close to measure the amount of light transmitted from the emitter-to the sensor by dispersion of the smoke particles.

Whenever the particles cooperate to measure the presence of light and determine if it exceeds a threshold amount, the emitter and the sensor need initial calibration and periodic testing to ensure that their optical response characteristics are within the limits nominal ratings. Old designs of photoelectric smoke point detectors suffer from the disadvantage of requiring periodic inspections of their metal accessory system and manual adjustment of electrical components to carry out a calibration sequence.

The North American patent application Series number 08 / 110,131 that appears presented in the name of Bernal and others people for a SMOKE DETECTOR SYSTEM WITH CHARACTERISTICS - AUTO DIAGNOSIS AND REPLACEABLE SMOKE TUBE FOR SMOKE- ("Application '131"), filed on August 19, 1993, assigned to Sentrol, Inc., of Tualatin, Oregon ("Sentrol"), which is precisely the assignee of the present application, incorporate The application '131 to this description as a reference, describes a novel design of a smoke detector, which is the Sentrol Model No. 400, which has a relocatable canopy and internal auto features. diagnosis, to determine and indicate 'when it is out of calibration. 20 The old designs and the Sentrol Model No. 400 over time suffer a change in their sensitivity to smoke. A smoke detector, photoelectric, point, can become more - sensitive to smoke as the surfaces inside are contaminated with particles, such as dust particles or - less sensitive to smoke, as the intensity of the smoke Issuer emission decreases with time in operation. Such changes can cause a smoke detector to indicate an alarm location when it does not exist (over-sensitivity) or not to indicate an alarm situation when it really exists - (low sensitivity).

Such changes in sensitivity travel without being detected when the inspection is not carried out with the old designs; they are indicated by the Sentrol Model No. 400. - However, in the older designs and in the Sentrol Model No. 400, the changes in their sensitivity persist until a human being intervenes. It is expensive to inspect older designs to detect loss of sensitivity and keep them, and even replacing the canopy of a Sentrol Model No. 400 has a cost. Also, a replaceable canopy can not have the uniformity of response between different canopies, which is characteristic of the canopy of the Sentrol Model No. -400. Without such uniformity of response, replacing the dyes will change the sensitivity of the older designs of smoke detectors.

SUMMARY OF THE INVENTION It is an object of the invention, therefore, to increase the time before a smoke detector becomes sufficiently hyper or infra sensitive to service or replace it.

An advantage of the invention is that it allows a longer time between the replacements of a canopy in a smoke detector, such as the Sentrol Model No. 400.

Another advantage of the invention is to provide a smoke detector that self-adjusts to gain or lose sensitivity after installation.

Another additional advantage of the invention is to provide a self-adjusting smoke detector for differences in sensitivity due to differences between a removable canopy that has been in service in the smoke detector and the replacement of a canopy that is, either, new, cleaned, or that has not been in service in that smoke detector.

Still another advantage of the invention is to provide an integral smoke detector which is alert against false alarms, but which quickly signals situations or alarm conditions.

One aspect of the present invention is an integral smoke detector having such self-adjusting i-ternal characteristics. The smoke detector includes a smoke-sensitive element, for example, the combination of LED-photo diode used in the Sentrol Model No. 400. It also comprises a sampler that shows the output of the smoke-sensitive element for produce a succession of indicative samples of the smoke level in the respective plural sampling times. The output of the sampler leads to an alarm control circuit, for example, a microprocessor. The smoke-sensitive element and the alarm control circuit are mounted in a discreet housing. 10 There is a direct correlation between a change in - the output of the smoke sensitive element over a time interval greater than the time in which a slow fire occurs and - the sensitivity of that sensor. Therefore, through the In the case of termination of such changes in the output of the sensor, the smoke detector can determine when it has become either low in sensitivity or over-sensitive. The microprocessor makes appropriate adjustments to neutralize the changes in sensitivity by carrying out an algorithm defined by means of ins operations stored in the firmware. The algorithm determines a float setting and uses it to adjust the untreated data provided by the smoke sensitive element. The microprocessor compares the data thus adjusted with an alarm threshold stored in the memory and indicates an excessive smoke level if the adjusted data exceed the alarm threshold. The microprocessor then determines whether it signals or warns about an alarm situation or condition.

Another aspect of the invention consists of a method 5 of operating a smoke detector. The method includes producing signal samples that indicate measurements of a smoke level in a region or space; Samples include a sample - current and previous plural samples. An alarm threshold is established, preferably in a calibration phase. 10 An adjustment is determined based on selected samples. The current sample, the alarm threshold and the adjustment are used to determine if the current or present sample indicates an excessive level of smoke. Therefore, it is determined if an alarm signal occurs.

Additional objects and advantages of the present invention will be apparent from the following detailed description of a preferred embodiment thereof, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagrammatic view of a blog diagram showing a smoke detector according to the invention, connected to a control panel.

Figure -2 is a schematic diagrammatic view of an alarm control circuit shown in Figure 1.

Figure 3 is a flow diagram showing steps or steps that are carried out in the factory during the calibration of the smoke detector.

Figure 4 is a flow diagram that summarizes - the steps or steps performed by a microprocessor that is shown in Figure 2 when a self-adjustment is carried out, - determining if there is an alarm situation or condition and - leading to out a self-diagnosis.

Figure 5 is a more detailed version of the flow diagram 15m of Figure 4.

Detailed description of a Preferred Modality With reference to Figure 1, an integral smoke detector 20 is used to determine whether at a point 11 in a region or restricted space 12 being monitored, - a sufficiently high level of smoke exists (for example, in air environment in item 11) that an alarm situation or condition should be indicated, a signal of -2 alarm being produced in a signal path 16, to a control unit op nel 18. Region 12 may, but not necessarily have - to be at least partially restricted by the surfaces 19. The smoke detector 10 includes a smoke-sensitive element 20, which measures the smoke level at a point 11 and provides precautionary measures above the path of smoke. signal 22 to an alarm control circuit 24, a sensitive element signal or untreated data;, that is, data that has not yet been adjusted as described below, which indicates that level of smoke . The smoke sensitive element 20 and the alarm control circuit 24 are each mounted in a discrete housing 25 which operatively operates the smoke sensitive element 20 to the region 12 and which mounts the sensitive element 20 the smoke and the alarm control circuit 24 to point 11. The housing 25 can, but does not necessarily incorporate a replaceable canopy, for example. pio, the replaceable canopy of the Sentrol Model No. 400 that IflP describes in Application '131. The housing 25 may have openings 25A that admit ambient air 14 with any associated smoke for measurement by the. element 20 sensitive to smoke. The smoke sensitive element 20 is, for example, a scattering LED-photodiode sensor that detects scattered light of smoke particles (the "dispersion implementation"), as described in the '131 Application. The alarm control circuit 24 controls the activation of the smoke sensitive element 20 above the path 26 of signal. The control panel 18 again places or resets the alarm control circuit 24 above the signal path 28.

Figure 2 is a schematic view of a block diagram showing details of the alarm control circuit 24. The circuit 24 includes a processor or microprocessor 30 to which a non-volatile memory 32 is connected, for example, an electrically programmable memory and capable of being erased only by reading, over a path 34 of signal and a clock oscillator and circuit 36 of wake up above the signal path 38. A set of instructions for microprocessor 30 is contained in the memory only by internal reading to the microprocessor 30. The memory 32 supports certain operating parameters that can screen later and that are determined during the calibration. Untreated data of the smoke sensitive element 20 can lie above the signal path 22 to an optional signal acquisition unit 40, which converts or - conditions the raw data, which are, for example , - 20 analogous data, to a digital form UNTREATED DATA (RAW DATA) and then transports that digital form over the signal path 42 to the microprocessor 30. In the implementation of the dispersion, the acquisition unit 40 The signal includes an analog-to-digital converter ("A / D") which is described in the application '131, to convert the analog output of the photodiode to digital form. If the element 20 sensi. When the smoke produces its untreated data output in a form, either analogue or digital, that microprocessor 30 can receive directly, then the signal path 22 can transport that data without directly processing to the microprocessor, which it produces from that data without addressing the - digital representation UNTREATED DATA (RAW DATA) on which it operates.

To reduce the energy requirements of the smoke detector 10, the microprocessor 10 is preferably inactive or "asleep", except when it is periodically "awakened". The clock oscillator and the piecing circuit 36 may, depending on the selected microprocessor, to be internal or external to the microprocessor 30. Also, to reduce the energy requirements, the microprocessor 30 activates the smoke sensitive element 20 above the signal path 26 to test the smoke level in the region 12 (FIG. 1) . However, any form of sampling that produces samples of the output of the smoke sensitive element 20 is adequate at appropriate times. The sampling produces successive samples, each of them indicative of a smoke level in the respective one, of successive sampling times or moments.

Jai The microprocessor 30 is repositioned above the line 28 by the control panel 18 (Figure 1).

The self-adjustment and self-diagnostic characteristics of the smoke detector 10 depend on calibrating the electronic sensors and storing certain parameters in the memory 32. Figure 3 is a flow diagram showing the steps or calibration stages that are carried out in the factory. The process block 44 indicates the measurement in a medium known as being smoke free from a clean air signal or clean air data sample (CLEAN AIR). which represents a smoke level of 0 percent. In the implementation of the dispersion, the clean air voltage of the photodiode is around 0.6 volts, which typically becomes a digital word equably deciphering 120. Upper and lower limits of tolerance, used in auto -diagnostics, are placed in + 42 percent - of CLEAN AIR. (CLEAN AIR).

The process blog 46 indicates adjustment of the output of the smoke sensitive element 20 and any signal acquisition unit 40. This is achieved by placing the smoke sensitive element 20 in a chamber having a simulated smoke environment representing a calibrated level of smoke. Since the calibrated level of smoke is constant in said environment, the smoke sensitive element 20 produces a constant output; parameters of the smoke detector 10 are adjusted to assign a calibrated value to that output. In - the implementation of the dispersion, the gain of the convert A / D is set as described in the application '131, - so that the smoke sensitive element 20, in that simulated smoke environment, and the signal acquisition unit 40, reach, a voltage threshold alarm (typically around 2.0 volts) that typically becomes a digital word equates to around 230-235 decimals, for a smoke obscuration level of 3.1 percent per foot.

The procedure blog 48 indicates the determination of an alarm threshold corresponding to an output of the smoke sensitive element -15 indicating the presence of excessive smoke in the region 12 and in response to which a signal should be signaled. situation or alarm condition. In the dispersion implementation, the alarm threshold is the threshold at which the gain is calibrated (procedure block 46).

^ At the end of the calibration procedure, the output of the smoke sensitive element 20 and any signal acquisition unit 40 are calibrated and the values for AIR_ CLEAN, the lower and upper tolerance limits and the alarm threshold are stored in the memory 32. Each of these values is specific to the individual smoke detector 10 that was calibrated. Also, stored in memory 32 are ADJISENS and ADJSENS values for a range limit, the use of which is described below.

The self-adjusting and self-diagnostic features of the invention, as implemented in the algorithm described in relation to Figures 4 and 5, rely on the existence in the smoke-sensitive element 20 of a linear relationship between the output of that sensor and the smoke level. That relationship can be expressed as: y = m * x + b, where y represents the sensor output, m represents the gain (defined for a scatter sensor as the change -in the sensor output by percentage of obscuration per foot), and b represents the clean air output. In the implementation of the dispersion, the gain is not affected by an accumulation of dust or other contaminants. Any smoke-sensitive element in which the gain is not affected by factors that cause a change in sensitivity, can be employed as a smoke-sensitive element with the algorithm of Figures 4 and 5.

A change in sensitivity causes the smoke sensitive element ßk 20 to produce, under conditions in which smoke, indicative of an alarm situation is not present ("non-alarm conditions"), a different output of CLEAN AIR. Whenever the output of the element 20 responsive to If smoke in such conditions rises, the smoke detector 10 becomes more sensitive, since it will produce an alarm signal at a smoke level that is lower than the alarm threshold. This can cause false alarms. On the contrary, provided that the output of the smoke-sensitive element 20 in such a condi If the pressure falls below the clean air voltage measured in the calibration, the smoke detector 10 becomes more sensitive since it will not produce an alarm signal until the level of smoke exceeds the level at which the threshold of the smoke was placed. alarm. This may cause delays in the alarm signal, or it may not occur.

Since the gain is constant even with changes for additional time at exit in non-alarm conditions, there is a direct correlation between a change in the output voltage in non-alarm conditions and a change in - sensitivity. The invention exploits that correlation by using certain additional time changes in the output of the smoke sensitive element 20 as a basis for sensitivity change adjustment to keep the smoke detector 10 with the sensibi the capacity with which it was calibrated.

*. The self-adjusting procedure that the microprocessor 30 executes is designed to correct, within certain limits, changes in the sensitivity of the smoke detector 10, while retaining the effectiveness of the smoke detector 10 in detecting fires. The self-adjusting procedure relies on the fact that a change in the output of the smoke-sensitive element 20 over a data collection time interval that is long compared to the time of combustion of a fire. slow in region 12 usually results, not from a fire, but from a change in the sensitivity of the system. The microprocessor 30 uses said change as a basis for determining a float setting (FLT_ADJ) which is used to adjust the unadjusted, the untreated output or the digital word UNDETECTED DATA (RAW_DATA) to produce a value of adjusted data (ADJ_DATA) that is typically closer to the CLEAN AIR than is the reading of UNDETECTED DATA (RAW - DATA). The adjusted data (ADJ DATA) is then used for the alarm test and for self-diagnosis. The - float adjustment (PLT ADJ) is positive or negative when the The smoke detector 10 has become less sensitive or more sensitive, respectively, than it was when carrying out the calibration.

Figures 4 and 5 are flow diagrams showing an algorithm or routine 50 implemented in a microprocessor 30 to carry out the self-adjustment, the test of the -alarm and the self-diagnosis as particularities or characteristics of the invention. The microprocessor 30 receives the successive signal samples produced by the smoke sensitive element 20 and uses those samples for three objectives.

First, the microprocessor 30 determines the successive flotation settings or the values of the flotation setting (FLT ADJ) with the use of the signal of the sensing element or untreated data (RAW_DATA) that occur during the corresponding of the Time intervals for obtaining successive data or periods of 24 hours (figures 4 and 5, blog 58, 60 of procedure). Each data collection time interval extends a data collection period or 24 hours. Each flotation setting is at least indicative - in part, of relationships between raw data (RAW_DATA) in the 24-hour period and clean air (CLEAN_AIR).

Typically, the value of the float adjustment (FLT ADJ), or at least the trend of a float adjustment value (FLT_ADJ) at the next successive value, is generally indicative of whether the raw data (RAW DATA) is greater or less than clean air (CLEAN_AIR) in the corresponding 24-hour period.

In the preferred embodiment the flotation setting (FLT ADJ) is updated (after its start) once every 24 hours on the basis of selected samples produced in those 24 hours.

Second, the microprocessor 30 determines, in successive levels of smoke level determination (Figures 4 and 5, process blocks 56 and 62) whether the output of the sensitive element 20 or the raw data (RAW DATA) indicate a - excessive level of smoke at point 11 in region 12. This is done with the use of an alarm threshold, the signal of the sensitive element and one of the float settings corresponding to the time of determination of level of smoke. smoke. The cor- respondence of the flotation settings used has as its data collection time interval, one which is sufficiently recent at the time of determination of the smoke level that the signal of the sensitive element in the absence of smoke is not likely to have changed. Significantly from the time interval of obtaining data at that time -determination of smoke level. In the preferred embodiment, the float adjustment value (FLT_ADJ) is typically used in the 24-hour period immediately after the 24-hour period which is the typical data collection time interval for that float adjustment value ( FLT_ ADJ). Therefore, the data retrieval time for that float adjustment value (FLT_ADJ) is within 48 hours before the value of the float adjustment (FLT_ADJ) is used. During that clear time of 48 hours, the response of the sensitive element 20 in the absence of smoke is not likely to change significantly in the typical 12 regions. In principle, a value of the flotation setting (FLT_ADJ) that occurred on the base of a data acquisition time interval greater than 48 previous hours (still one year earlier) than the value of the fleet adjustment The measurement (FLT_ADJ) at a smoke level determination time could produce acceptable results for some regions 12.

If a data acquisition time interval is sufficiently recent with respect to a smoke level determination time for a given float setting 1 on the basis that this time interval for obtaining data is used in that time of determination of the level - of smoke, depends, for example, on the speed of the change signi. in the signal of the sensitive element in the absence of smoke and the desired degree of fidelity of the flotation adjustment (FLT ADJ) at that time of determination of the smoke level.

Third, the microprocessor 30 determines, with the use of a determination of an excessive level of smoke, if - it indicates the existence of an alarm situation activating its alarm signal above the line 16. The microprocessor 30 activates its alarm signal only when it has determined that the adjusted data (ADJ_DATA) exceeds the alarm threshold by a predetermined time or by a predetermined number of samples, or samples of three consecutive signals. Such confirmation of an alarm situation provides a greater advantage over conventional smoke detectors and smoke detector systems. Each false alarm puts the life of firefighters at risk by traveling to the scene of the false alarm, reduces the capacity of firefighters to respond to real alarms and imposes unnecessary costs. Selecting the predetermined time or selecting a predetermined number of samples of consecutive signals involves considering the need for an indication -fast of a true alarm situation against the need to avoid false alarms.

Specifically, Figures 4 and 5 show (in full outline) certain procedures or decisions that the micro processor 30 carries out in each execution of the routine 50 and (in irregular contour) other procedures or decisions - which it carries out only in executions selected.

With reference to Figure 4, the microprocessor 30 carries out a routine 50 once every 9 seconds (except-when activated or when it is replaced, when it executes the routine 50 once every 1.5 seconds for the first four executions) , entering these stages in blog 52 of CORRIDA (RUN). As the first step, which is indicated by the process block 54, the microprocessor 30 acquires a digital word DATOS_SIN TRATAR (RAW DATA) with a sensitive element signal or voltage from the smoke sensitive element 2Q or the acquisition unit 40. signal. The microprocessor 30 then uses a value simultaneously assigned to the float adjustment (FLT_ADJ) to adjust the data without tra-0 tar (RAW_DATA) to produce the adjusted data value (ADJ_ DATA) as indicated in block 56. procedural.

The following two procedural blocks, 58 and 60, indicate the procedures that the microprocessor 30 performs only at selected times indicated in more detail in relation to FIG. 5. To preserve the code in practical implementation, the conditions that with the input to the procedure block 58 can still be tested in runs of the routine 50, in which 0 said procedures are not to be carried out, and the procedure block 60 can be carried out in each execution - routine 50 even when it has the power to affect the value of the float setting (FLT_ADJ) only in executions - in which the float setting is changed (FLT__ADJ). The procedure block 58 indicates that the microprocessor 30 - starts or updates the float setting (FLT_ADJ). The procedure block 7 indicates that the microprocessor 30 - then limits the maximum value of the float setting (FLT ^ ADJ) not greater than a predetermined upper limit (ADJISENS.} And limits the minimum value of the float setting (FLT_ADJ ) to no less than a predetermined lower limit (ADJSENS) ADJISENS and ADJSENS limit the extent to which the smoke detector 10 will self-correct for the respective effects of insensitivity and oversensitivity, before indicating that service ADJISENS and ADJ- limits SENS are chosen together with tolerance limits, so that a self-diagnostic feature described below will indicate the need for maintenance while the smoke detector 10 is still operable to reliably detect fires. In the dispersion implementation, - 15 the ADJISENS limit corresponds to a change in the smoke obscuration level, of approximately 0.5 percent per foot or around 18 decimal places in the digital word - flotation adjustment (FLT__ADJ), and the ADJSENS limit corresponds to a change in the level of smoke obscuration of around 20 of the 1.0 percent per foot or about 35 decimals in that digital word. The ADJISENS limit is set so that the smoke detector 10 does not automatically produce an alarm signal when activating or returning to the initiation procedure described below. ^ -fe- As indicated by the procedure block 62, the microprocessor 30 then performs an alarm test using adjustment data (ADJ_DATA). Specifically, the microprocessor 30 compares the adjustment data (ADJ_ DATA) with the value of the alarm threshold set during calibration and stored in memory 32 and activates the alarm signal when the setting data (ADJ DATA) equals or - Jjj exceeds the threshold value of the alarm for three samples of consecutive signals or as described above. Enton ees, as indicated by the procedure block 64, the microprocessor 30 employs adjustment data (ADJ_DATA) to perform a self-diagnostic sensitivity test to determine whether it signals that the smoke detector 10 is sufficiently-out of adjustment to require service. When this task is complete, the microprocessor 30 terminates that execution of routine 50, as indicated by block 66 END.

Figure 5 shows the additional detail of certain parts of the routine 50. The procedure of adjusting data without Processing (RAW_DATA) (procedure block 56) includes setting adjustment data (ADJ_DATA) equal to raw data (RAW_DATA) plus float adjustment (FLT_ADJ) during each routine execution 50, except when activating or relocating the microprocessor 30. Activating or repositioning the setting of flotation (FLT_ADJ) is equal to setting the limit ADJI-SENS for the following four executions of routine 50. This adjustment ensures that even a detector 10 very insensitive to smoke adequately responds to situations of smoke by activating it or repositioning; for a smoke detector 10 which is less insensitive, the float setting (FLT_ADJ) is started quickly as described below.

The procedure of initializing or updating the flotation setting (FLT ADJ) (procedure block 58) -includes determining whether the float setting (FLT__ADJ) has been initialized (decision block 68). If this is not the case, as in the case of activating or replacing, the control passes via the connector A to the steps mentioned below in relation to the procedure block 100 (Figure 5-4). If so, the control passes to the procedure block 70, which indicates that the microprocessor 30 proceeds to determine the maximum and the minimum of certain averages of the flotation adjustment (FLT__ADJ) taken in a time interval of previous base or period that has a preferred base time duration of 24 hours.

Within the procedure block 70, the procedure block-72 indicates that the adjustment data (ADJ_DATA) -is stored every 30 minutes from its last storage. -The procedure block 74 indicates that, every two hours, based on a test average, a new average (NEW_AVG) was calculated last; the microprocessor 30 uses the last four stored values of the adjustment data (ADJ_DATA) to calculate the new average (NEW_AVG) as the average of those last four samples. Each value of the new average (NEW AVG) is then based on the respective of the non-identical sub-locations of the adjustment data samples (ADJ_DATA) produced within the respective intervals of plural adjustment time that have a time duration. of default setting.

The procedure block 74 indicates that the microprocessor 30 stores the maximum and minimum values of the new average (NEW_AVG) determined during a base-time interval of 24 current hours. The procedure block 76 indicates that at the end of the 24 hour base time interval the microprocessor 30 yields to a SELECT variable (used in the procedure block 78) any of the maximum and minimum of the new average (NEW_AVG) since The 24-hour period is the closest to clean air (CLEAN AIR). The use of the corresponding of the maximum and the minimum of the averages that is closest to the clean air (CLEAN_AIR) reduces the influence of passing or transient events through filtering based on the determination of the flotation adjustment (FLT_ADJ ) at least some of the samples that may indicate a smoke level in region 12; it also reduces the change made in the float setting (FLT_ADJ) in each of those settings. Since the SELECT is calculated only once every 24 hours after the initialization of the smoke detector 10, the float setting (FLT_ADJ) is changed only once every 24 hours. When making any change to the float setting (FLT_ADJ) (after it has been started) on the basis of data collected above a base time interval that is long compared to the time of slow burn combustion, which could occur in region 12 helps to ensure that the smoke detector 10 will accurately detect the alarm conditions.

The procedure of updating; that is, to increase or decrease, the float adjustment (FLT ADJ) (blog 78 -of procedure) limits the magnitude of any change in the float setting (FLT_ADJ) at the end of each 24-hour base time interval or period to equal or be less than a predetermined limit of 1.ca nls e, which also reduces the change made in the flotation adjustment (FLT_ADJ) in each update. The ratio of the limit of a l c to n s e - with respect to the values chosen for the adjustment ADJISENS and ADJSENS limits, determines the maximum number of days required for the smoke detector 10 to reach any-of those adjustment limits. In the dispersion implementation, the limit of a l c a n s corresponds to a change of 0.1-percent per foot in the level of smoke obscuration; that is, to a change of approximately 3 decimal places in the digital word float adjustment (FLT_ADJ). A variable float setting (FLT_ADJ) is set to be equal to the clean air CCLEAN_AIR) - SELECT (procedure block 80) and then limited in magnitude to the limit of a l c a n s e (procedure blog 82). The float setting (FLT_ADJ) is then updated by setting equal to the previous value of the float setting (FLT ADJ) plus float setting (FLT_ADJ) (procedure block 84). The procedure blocks 82 and 84 ensure that each of the values of the float adjustment (FLT_ADJ) is (with the exception of the ADJISENS value assigned to the float setting (FLT_ADJ) upon activation or reposition) within the limit of reached from the previous - - - immediate value of the float setting (FLT ADJ).

The procedure of carrying out the -alarm test (procedure block 62) includes determining whether -the adjustment data (ADJ_DATA) is equal to or exceeds the threshold of -alarm (decision block 86). Each routine run 50 then defines a smoke level determination time. The microprocessor 30 produces its alarm signal announcing the presence of an alarm situation, as indicated by the procedure block 88, only when the adjustment data (ADJ_DATA) is equal to or exceeds the alarm threshold for three consecutive signal samples, as described above.

The procedure of carrying out the sensibility test (procedure block 64) is as follows. The decision blogging 90 indicates the sequence comparison by means of the microprocessor 30 of the adjustment data (ADJ DATA) against the upper and lower limits of tolerance and the determination by means of the microprocessor 30, of whether the adjustment data (ADJ_DATA) falls within those limits. If so, the smoke detector 10 continues and, as indicated by the procedure block 92, a counter on the microprocessor 30 and having a module of 2 counts, monitors that the two consecutive amounts of adjustment data concur. (ADJ_DATA) that fall within tolerance limits. Otherwise, a counter is indexed through an account, as indicated by the procedure block 94. However, each time two quantities with set-up data (ADJ_DATA) appear within the tolerance limits, the counter of the two-count module re-sets the counter of the procedure block 94.

The decision block 96 represents a determination of whether the number of accounts accumulated in the counter of the process block 94 exceeds a number limit corresponding to consecutive values of the adjustment data (ADJ_DATA) under conditions of tolerance limit for each of the executions of the routine 50 in a predetermined time interval (for example, 24 hours). If so, the microprocessor 30 provides an indicator (not shown), for example, a disguised LED, visible from outside the smoke detector 10, as indicated in the process block 98. Other indicators, for example, an audible alarm or a relay output, can be used. The indicator indicates that the smoke detector 10 has been derived out of calibration to become either hyper or infra sensitive and needs to be serviced. Otherwise, the microprocessor 30 terminates its present execution of routine 50.

The sensitivity test algorithm provides a bearing measurement period out of tolerance that starts running as long as there are two sequential appearances of the adjustment data (ADJ_DATA) within the tolerance limits. The smoke detector 10 then monitors its sensitivity status without the need for manual evaluation. The use of the adjustment data (ADJ_DATA) instead of the untreated data (RAW_DATA) in the sensitivity test extends the time before the - smoke detector 10 indicates that it is out - calibration and then extends the service life of the Smoke detector 10 and / or - Reduces maintenance or service costs.

Referring to Figure 5-1, if the float setting (FLT_ADJ) is not initialized when entering routine 50, decision block 68 directs control through connector A to process blog 100 (FIGS. 5-4), which controls-initialization of the float setting (FLT_ADJ). The float setting (FLT_ADJ) is initialized for two reasons: (1) to establish in the installation an initial base value for the float setting (FLT_ADJ) in the environment in which the detector 10 is installed. smoke; and (2) to allow the smoke detector 5 to reestablish a base value for the float adjustment (FLT__ADJ) after a relocation of the microprocessor 30 in a commercial implementation that lacks a non-volatile memory to store the value of the Float adjustment (FLT_ADJ) through a relocation.

The initialization has two phases, represented by the two-directions of the procedure flow of the decision block 102, which indicates that the microprocessor 30 determines whether a complete first adjustment has taken place after the most recent activation or repositioning. The first phase makes a full adjustment of the float setting (FLT_ADJ); that is, - an adjustment that is not limited in magnitude by the limit of - - - alcanse. The procedure block 104 represents the calculation of a full average (FULL_AVG) variable, such as the average readings of the data ein treated (RAW_DATA) taken in the first four routine executions 50 after activation or relocation, spaced at a rate of 1.5 seconds from them. This operation rapidly establishes a pro-average total value (FULL_AVG) of the response of the smoke sensitive element 20 and any signal acquisition unit 40 to ambient conditions in region 12. The procedure blog -106 indicates that, to retract smoke detector 10 to the response that was established during calibration, the float setting (FLT_ADJ) is then set-to be equal to clean air (CLEAN_AIR) - FULL AVERAGE. (This occurs in the fifth execution of routine 50 after activation or repositioning, the float setting (FLT_ADJ) is placed in ADJISENS for the first four runs of -routine 50 after activation or repositioning (Procedure block 56 ( Figures 5-1),) That step or step is not limited by the limit of lcanse, therefore, after the procedure block 106, the control goes through the -connector D to the procedure block 60 (Figure 5-) 2) .

In the next execution of routine 50, the block 102 of decision passes the control to the second phase of the initialization, which allows the correction of the first complete adjustment, which could have been affected by a transient smoke event. The decision block 108 establishes an interval of 30 minutes after the first complete adjustment; until - the 30 minute interval is passed, the decision block 108 passes the control to the procedure block 110.

The procedure block 110 indicates that, within the 30 minute interval, the microprocessor 30 stores adjustment data (ADJ_DATA) every 36 seconds. The blog 112 of -procedure indicates that every 2.4 minutes, the microprocessor -30 calculates the average of the last four stored values of adjustment data (ADJ_DATA) and yields the value of that average to a variable initial average (INIT_AVG. procedure block 114 indicates that the value of the initial average (INIT_ AVG) is assigned to the variable SELECT before entering (via connector C) to procedure block 78 (Figure 5-2) to limit, through the limit of a l c a n c e, any increase or decrease of the float adjustment (FLT_ADJ) during the second phase.

Therefore, during the 30-minute interval, the float setting (FLT__ADJ) can be changed through the limit of one time every 2.4 minutes; that is, as many as 20 times. This operation quickly corrects the float setting (FLT ADJ) with respect to any transient smoke event that may have occurred while the data was being obtained to calculate the full average (FULL_AVG) - (procedure block 104).

The decision block 108 indicates that, when the interval of 30 minutes from the first complete adjustment has been transferred, the control is transferred to the procedure block 116, which indicates that an initialized float adjustment flag has been set. is located on the microprocessor 30. Next - from the process block 116, the microprocessor 30 proceeds through the connector B to the process block 70. In the next routine execution 50, the decision block 68 (Figure 5-1) recognizes that the flag is placed and transfers control to the process block 70, thereby bypassing the process block 100. The flag is cleared upon activation or relocation.

When the microprocessor 30 produces an alarm signal above the signal path 16 (Figures -1-2), the control panel 18 verifies the existence of an alarm condition before producing its own alarm signal, which it can be, for example, a ringing bell, a -siren sound, or a signal to the authorities, such as -police or firefighters. The control panel 18 checks an alarm situation by relocating the microprocessor 30 temporarily reducing the voltage of its power supply. The microprocessor 30 then executes the initialization procedure of the routine 50 in which the float setting (FLT_ADJ) is set as ADJISENS for the first four runs (procedure block 56) (Figure 5-1). If the microprocessor 30 then confirms the existence of an alarm situation by again producing its alarm signal above the signal path 16 as described above, the alarm situation is confirmed and the control panel 18 produces its own alarm signal. Such verification of an alarm situation also reduces the risk of false alarms. The invention makes it possible, in a smoke detector - which is adapted to receive a replaceable canopy - to replace a first canopy with a second canopy which is either new, cleaned, or has not been in service at that time. Smoke detector, even if the untreated data (RAW_DATA) in smoke smoke, have a quite different value for the two -sols. This difference may be due to the passage of time, as of the date of installation of the canopy; for example, to an accumulation of dust in the first canopy, which was not present in the second canopy, or may be due to differences between the two canopies; for example, when the two canopies produce a less uniform data adjustment value (ADJ_DATA) in the absence of smoke, which is produced by the design disclosed in the '131 Application.

The first replaceable canopy is installed in * the smoke detector 10, which is then operated as described above. The smoke detector 10 determines an appropriate float adjustment value (FLT_ADJ) for the first canopy and updates that value. The first canopy is then removed; for example, when the smoke detector 10 indicates that it is outside - of a tolerance limit, and the second canopy is installed - in the smoke detector 10. Typically, the value of the untreated data (RAW_DATA) in the absence of smoke is different from the second installed canopy than it was with the first canopy.

However, the smoke detector 10 simply adjusts the value of the float setting (FLT_ADJ) to be suitable for the second canopy. This can be done relatively quickly by being repositioned and thus initialized by sending the signal relocated from the control panel - 18 after the second canopy has been installed. (Such recolor location and initialization could alternatively be initiated through a manual relocation button or a magnetically powered nozzle switch (also not shown) in the smoke detector 10.) Or it can be so by executing routine 50 without repositioning or by initialization and, in this way, adjust the float setting (FLT ADJ) to a value appropriate to a second canopy over a few or many days, OR if, replacing the first canopy with the second triggers, - a signal of alarm on line 16, repositioning and initialization triggered by control panel 18 on line 28 to confirm the existence of an alarm situation could adjust the float setting (FLT_ADJ) relatively quickly if the Relocation and initialization occur after the second canopy has been installed.

Many changes can be made to the details of the preferred embodiment described above of the present invention, without departing from the underlying principles thereof. The microprocessor 30 could employ a float setting (FLT_ADJ) to modify the alarm threshold and - the upper and lower sensitivity thresholds. The flotation averages could be determined by averaging the output of the smoke sensitive element 20 over the corresponding data acquisition time intervals. The alarm control circuit 24 can employ analog acquisition instead of digital acquisition of the output of the smoke sensitive element 20. An example of analog acquisition is the accumulation of voltage through a capacitor. Analogous acquisition is typically less preferred than digital acquisition, due to its normally slower response time and lower flexi-lity. The alarm control circuit 24 may also acquire values from the output of the smoke sensitive element 20 - continuously rather than by sampling. The continuous acquisition of data is typically less preferred than sampling, because of its normally higher energy regresses. The smoke sensitive element 20 can use as a source of radiation, a source of particles instead of electromagnetic radiation, or it can detect smoke by detecting the presence of ions associated with smoke. When the smoke-sensitive unit 20 is an ion detector, it need not be -wrapped by the housing 25. The scope of the present invention should, therefore, be determined only by the following claims.

Claims (33)

* R E I V I N D I C A C I O N E S

1. A smoke detector, integral and self-adjusting, comprising: a smoke-sensitive element operable to produce a sensitive element signal, indicative of a smoke level, in a space or region; - * an operable alarm control circuit for terminating successive flotation settings with the use of the signal from the sensing element produced during the corresponding successive intervals of data acquisition time, extending each data acquisition time interval, a data collection duration, each float setting indicative, at least in part, of relationships between the signal of the sensing element in the corresponding data acquisition time interval and a clean air signal produced through the sensing element in clean air; 20 The alarm control circuit is also operable - with the use of an alarm threshold, the signal of the sensing element and the corresponding one of the successive flotation settings to determine in successive determination times of smoke level, if the signal of the sensitive element indicates an excess level 25 smoke in the region, the corresponding one of the settings - of flotation having as its corresponding data collection time interval, one that is sufficiently recent with respect to the corresponding smoke level determination time that the signal of the sensitive element in the absence of smoke it is unlikely that it has changed significantly from the data collection time interval to that smoke level determination time; the alarm control circuit also operable with the use of a determination of an excessive level of smoke, to indicate the existence of an alarm situation; Y a discrete housing that is on the sensitive element and the alarm control circuit and that -accessively engages with the sensitive element towards the region of space.

2. The smoke detector in accordance with that claimed in clause 1, wherein the alarm control circuit is operable, with the use of the alarm threshold, the signal of the sensitive element and one of the two more recently -produced adjustments of flotation, to determine if the signal -of the sensitive element indicates an excessive level of smoke in the -region.

3. The smoke detector in accordance with that claimed in clause 1, wherein the alarm control circuit is operable, with the use of the alarm threshold, the signal of the sensitive element and the most recently produced float adjustment, for determine if the signal from the sensing element indicates an excessive level of smoke in the region. 5

4. The smoke detector in accordance with Clause 1, where the data collection time is greater than an expected combustion time of a slow fire in the region. 10

5. The smoke detector according to the rei > vindicated in clause 1, wherein the alarm control circuit is further operable to produce an alarm signal - when it has detected an excessive level of smoke for more than one - predetermined time interval. 15

6. The smoke detector in accordance with that claimed in clause 1, wherein the alarm control circuit comprises: a processor operable to receive successive samples of the signal from the sensing element, the samples including a sample corresponding to each smoke level determination time and samples produced during each of the data acquisition time intervals; the processor is further operable to determine - at each successive flotation setting at least in part, selected samples produced during the corresponding data acquisition time interval; The processor is also operable to determine in 5 each smoke level determination time, with the use of the - alarm threshold, the sample corresponding to that smoke level determination time, and the corresponding float adjustment, if that sample indicates an excessive level of smoke in - ^ B the region.

7. The smoke detector in accordance with that claimed in clause 6, wherein the alarm control circuit is further operable to produce samples corresponding to an alarm signal when it has determined that samples - corresponding to a number The predetermined times of determi- nation of smoke level are indicative of the presence of excessive smoke level.

8. The smoke detector in accordance with Clause 6, where the selected samples 0 are chosen to filter from the determination of successive flotation settings, at least some samples that may indicate an aberrant level of smoke in the region.

9. The smoke detector in accordance with the claim 25 vindicated in clause 6, where the samples are produced - periodically.

10. The smoke detector in accordance with that claimed in clause 6, wherein the processor is operable to determine plural test averages, each based on the respective non-identical plural subgames of the selected maters, and to determine the adjustment of flotation with the use of the corresponding of the highest and the lowest of the test averages that is closest to the air signal -clean.

11. The smoke detector as claimed in clause 10, wherein the processor is operable to determine each test average based on an average-of a predetermined number of consecutive samples.

12. The smoke detector according to the claim in clause 6, wherein the processor is of a digital type.

13. The smoke detector according to the claim in clause 6, wherein the processor is of a type based on a microprocessor.

14. The smoke detector according to clause 1, wherein the float setting is not greater than a predetermined upper limit.

15. The smoke detector in accordance with Clause 1, where the float setting is not less than a predetermined lower limit.

16. The smoke detector in accordance with that claimed in clause 1, wherein each float setting has a value that is within a limit of -. * -.- - -allows default of the value of a float adjustment immediately previous.

17. The smoke detector according to the claim in clause 1, wherein the signal of the sensitive element is indicative of a level of smoke dispersion.

18. A method for operating a smoke detector, comprising: mounting a smoke-sensitive element and an alarm-control circuit in a discrete housing that operatively couples the smoke-sensitive element to a region or space, the sensitive element thus coupled, a response in smoke-free, which can vary with time; set an alarm threshold; produce with the sensitive element, a signal of -sensitive element indicative of a level of smoke in the region; determine with the alarm control circuit, -one of the successive flotation settings with the use of the signal of the sensitive element produced during the corresponding one of the successive intervals of data acquisition time, extending each time interval of obtaining of data a duration of obtaining data; each indicative float setting, at least in part, of ratios between the signal of the sensitive element in the corresponding time interval of obtaining data and a signal of clean air produced by the sensitive element in clean air; 10 determine with the alarm control circuit, in successive times of determination of smoke level, with the use of the alarm threshold, the signal of the sensitive element, and the corresponding one of the successive adjustments of flotation, if the signal of the sensitive element indicates an excessive level of smoke in the 15 gión, having the corresponding of the flotation settings - as its corresponding data collection time interval, one that is sufficiently recent with respect to the corresponding alarm determination time that the response of the - sensitive element in the absence of smoke it is not likely to have changed significantly from the data collection time interval with respect to that smoke level determination time; Y determine, with the use of a determination of an excessive level of smoke, if it indicates the existence of an alarm situation.

19. The method in accordance with claim-in clause 18, wherein in determining whether the signal of the sensitive element indi- cates an excessive level of smoke, comprises the -determining, with the use of the signal of the sensitive element, one -of the two most recently produced float settings, and the alarm threshold, if the signal from the sensitive element indicates an excessive level of smoke in the region.

20. The method of compliance with claim-in clause 18, wherein in determining whether the signal of the sensitive element indicates an excessive level of smoke, comprises the -determine, with the use of the signal of the sensitive element, the -more recently produced float adjustment, and the alarm threshold, if the signal of the sensitive element indicates an excessive level of smoke in the region.

21. The method of compliance with the claimed - in clause 18, where the duration of data collection - is greater than an expected time of combustion of a slow fire in the region.

22. The method of compliance with the claim - in clause 18, where the determination of the flotation adjustment includes: producing successive samples of the signal from the sensitive element, the samples including a sample corresponding to each smoke level determination time and samples - produced during each of the data collection time intervals; determining each successive flotation adjustment, at least in part, of selected samples produced during the corresponding data collection time interval; Y * x determine in each smoke level determination time, with the use of the alarm threshold, the sample corresponding to that smoke level determination time, and the corresponding float adjustment, if that sample indicates a There is no excessive smoke in the region.

23. The method according to claim 5 in clause 22, wherein the selected samples are periodically produced.

24. The method according to claim - in clause 22, wherein the determination of the float setting corresponding to a time interval of obtaining data, comprises: determining each of the plural test settings based on the respective plural non-identical subgames of selected samples produced within that time interval; determine a maximum and a minimum of those test settings; Y determine that float setting based on the -corresponding maximum and minimum that is closest to the clean air signal.

25. The method according to claim as claimed in clause 24, wherein the samples selected in each sub-game are produced within the respective plural adjustment time intervals, each of them having a predetermined adjustment time duration.

26. The method in accordance with what is claimed - in clause 24, where the determination of each test setting includes: determine an average of the samples selected in the sub-location. to which corresponds that test setting; Y use the average to determine the test setting for that subcolocation;

27. The method of compliance with claim-in clause 18, wherein the float adjustment is not greater than a predetermined upper limit of float adjustment.

28. The method of compliance with claim-in clause 18, wherein the float adjustment is not less than a lower predetermined limit of float adjustment.

29. The method of compliance with that claimed in clause 18, wherein each float adjustment has a value that is within a limit of .alphase of the value of the immediately preceding float adjustment.

30. The method in accordance with that claimed in clause 18, wherein each of the samples is indicative of the respective plural measures of a level of -dispersion of smoke in the region or space.

31. A method of operating a smoke detector has a light emitting device, a light sensor that receives light emitted by the light emitting device, and an alarm control circuit and which is adapted to receive a replaceable canopy covering the light emitting device and sensor and having openings that operatively couple with the light-emitting device and the light sensor to a region or -space to be -monitoring for smoke level effects, which comprises: install a first re-emplasable canopy in the smoke detector; operate the smoke detector, so that the detector determines a float setting, which has a value that is appropriate to the first replaceable canopy; remove the first replaceable canopy and install in the smoke detector a second replaceable canopy for which a different float adjustment value is appropriate than the value used for the first canopy; Y adjust the float setting to the different value.

32. The method of compliance with that claimed in clause 31, wherein adjusting the float setting comprises initiating the smoke detector.

33. The method of compliance with that claimed in clause 31, wherein adjusting the flotation adjustment comprises: producing with the light sensor a signal of the sensitive element indicative of a smoke level in the region; determine with the alarm control circuit, -one of the successive float settings with the use of the signal of the sensitive element produced during the corresponding one of successive intervals of data acquisition time, extending each of the time intervals of data acquisition, a data collection duration, each float adjustment indicative, at least in part, of relationships between the signal of the sensing element in the corresponding interval of fr of time of obtaining data and a clean air signal produced by the sensitive element in clean air. • *