GB2534957A

GB2534957A - A gas detector

Info

Publication number: GB2534957A
Application number: GB1514593.1A
Authority: GB
Inventors: Summerfield Adrian
Original assignee: Crowcon Detection Instruments Ltd
Current assignee: Crowcon Detection Instruments Ltd
Priority date: 2015-02-02
Filing date: 2015-08-17
Publication date: 2016-08-10
Also published as: GB201514593D0; GB201501699D0

Abstract

A gas detector has a gas sensor and a processor and a memory. The detector can switch between two states. In a first state S101, concentration of a target gas is detected, and a measurement response produced for recording in the memory. In a second state S103, the gas sensor does not detect the presence of the target gas. Input to an input sensor within the detector S104 causes retrieval of the measurement response from the memory. The input sensor provides an output indicative of a physical parameter associated with the gas detector which may be a user input, or a device detecting motion. The measurement response may be short or long term exposure level, and may be deleted from memory S115 if not retrieved or updated in the active state. Exposure data may be displayed or transmitted externally.

Description

A Gas Detector

Field of invention

The invention relates to improvements to gas detectors for measuring a response to a first target gas. Particularly, but not exclusively, it relates to a gas detector for measuring exposure data.

Background to the invention

It is known that a measure of the exposure of a user to a gas over a period such as a work shift is required in order to ensure that the user is not exposed to a dangerous level of a gas. Usually gas detectors calculate and record a user's exposure to a target gas. Typically such gas detectors discard the exposure data when the detector units are deactivated for longer than a period of time, assuming a user's shift has ended. This period of time is typically 15 minutes and represents a reset time after which the exposure data is reset to zero.

It is also known that a user may be required to travel between multiple sites within a single shift or otherwise take a break over which the user may deactivate the gas detector to save energy. In the cases where this results in the gas detector being turned off for longer than the reset time, the exposure data will be reset during the shift and the exposure data recorded at the end of the shift.

The exposure of a user to a target gas is often defined as a Short Term Exposure Level (STEL) or Long Term Exposure Level (LTEL). The STEL is often defined as the acceptable exposure to a target gas over a period of time, typically 15 to 30 minutes, as long as the time average exposure over the period of time is not exceeded. The LTEL defines the acceptable exposure to a target gas over a long period of time, typically 8 hours. STEL and LTEL values are typically set by government bodies and must be adhered to in order to ensure the safety of workers.

any to improve the accuracy of the measurements of STEL and LTEL values is desirable.

An object of the present invention is to mitigate some of the deficiencies of the prior art mentioned above.

Statements of Invention

In accordance to an aspect of the invention, there is provided a gas detector for measuring a response to a first target gas, the gas detector comprising a gas sensor configured to detect the presence of the first target gas, said gas sensor in communication with a processor and then a memory, with the features communicating in a known way, wherein the gas detector has: a first active state in which the gas sensor detects the concentration of a target gas, and produces a measured response for recording in the memory, and a second inactive state wherein the gas sensor does not detect the presence of the target gas, wherein the gas detector is configured to selectively switch between the two states, and the gas detector has signal receiving means configured to check for the presence of a signal, and based on the signal, trigger the retrieval of the measured response from memory. The signal receiving means and the signal in an embodiment are of the form of an input sensor and an input.

The fact that the gas detector has a memory configured to store and retrieve a measured response across a state of deactivation allows for the preservation of data that would otherwise be lost when the gas detector is deactivated. This allows the detector to more accurately determine the exposure to a target gas across a period of time that may include one or more instance of the gas detector being deactivated for a period longer than the reset time. This leads to more accurate data being available to the user.

Preferably, the measured response is an exposure value. The gas detector is particularly useful for monitoring exposure data for a user. The accurate recording of user exposure reduces the risk of overexposure.

Preferably, the exposure value is one or both of the Short Term Exposure Level (STEL) or Long Term Exposure Level (LTEL). These represent the industry standard workplace the gas detector may therefore ensure users adhere to official regulations pertaining to exposure to hazardous materials.

Preferably, the signal is a user input. This provides increased user control, which allows a user to indicate whether stored data should be retrieved, for example, in the case of a user continuing a shift, or whether stored data should be ignored, for example, if transferring the gas detector to a new user.

Preferably, the user input is made in response to a user prompt. This indicates that the gas detector is awaiting input and reminds the user to select the appropriate option regarding the use of any stored data.

Alternatively, the signal may be provided by a sensor within the gas detector. This allows the gas detector itself to determine whether or not to retrieve any stored data, without the need of any additional external control, lessening the possibility of user error or misuse of the device and reducing reliance on any supplementary hardware or control systems outside of the gas detector itself Alternatively, the signal is a transmission received from a remote transmitter. This allows for data retrieval to be controlled from a central control station, lessening the possibility of user error or misuse and providing for centralised control over multiple devices.

Preferably, the sensor is a GPS device. This allows the gas detector to determine if it is being transported, for example, between usage sites by a user. The detector can therefore self-determine whether any stored data should be retrieved in order to continue to measure exposure data for the user at the new site. As such the detector can, without requiring any input for any external sources, determine whether it has changed location, when determining whether the stored data should be retrieved.

Preferably, the gas detector can switch state as a result of user input. This allows the user to place the gas detector in an inactive state wherein some of its functionality is This allows the device to save energy whilst in an environment in which gas detection is not required.

Preferably, the exposure data is displayed to a user. This allows the user easy access to important information throughout a work shift.

Preferably, the exposure data is transmitted to an external location. This allows a single, or multiple, users' exposure to be monitored remotely.

Other aspects of the invention will be apparent from the appended claim set.

Brief description of the drawings

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic of a gas detector in accordance with an embodiment of the invention; and Figure 2 is a flow chart of the method in accordance with an embodiment of the 20 invention.

Detailed description of an embodiment

In order to provide a gas detector capable of more accurately recording exposure to a target gas across a period of time that contains one or more periods over which the detector is deactivated for longer than the reset time, there is provided a gas detector 10 in accordance to the present invention.

Figure 1 shows a schematic of a gas detector 10. The gas detector 10 comprises at least a housing 11 in which there is at least a gas sensor 15, a processor 20, a memory 25, and an input sensor in the form of a user input means 30 and/or a motion detection means 32. The input sensor in an embodiment comprises signal receiving means 33, with a signal being generated externally and broadcast to the gas detector 10.

The housing 11 in a preferred embodiment is rugged housing in which is placed the gas sensor 15, a processor 20, a memory 25 and an input sensor in the form of either a user input means 30 and/or a motion detection means 32 and/or signal receiving means 33.

The gas sensor 15 is a known gas sensor and configured to the presence and preferably the concentration of one or more target gasses. The processor 20 is configured to receive data from the gas sensor 15 and from the data the processor is configured to produce exposure data to the target gas. The processor 20 produces the exposure data from the gas sensor 15 data in a known manner.

The detector further comprises a form of memory, preferably non-volatile memory, and the processor 20 is configured to write data, such as the calculated exposure data to the memory 25. The memory 25 is capable of storing data when the gas detector is deactivated.

In one embodiment, the gas detector 10 comprises a user input means 30. The user input means in an embodiment is an actuation means, in a preferred embodiment a button. In further embodiments the user input means is an alphanumeric keypad, with which the user may input one or more commands. As such any known suitable means for enabling a user to input a command to the device 10. Such user input means 30 are known in the art.

In an alternative embodiment, the gas detector 10 comprises a motion detection means 32. The motion detection means 32 in an embodiment is an accelerometer and/or gyroscope. In further embodiments the motion detection means 32 comprises a known GPS unit, and the processor 20 is configured to query the GPS unit at regular intervals in order to determine the position of the unit. From such data any motion and resulting displacement of the device may be determined. As such any suitable means for determining whether the detector 10 has moved i.e. has been displaced, and/or is in motion may be used.

It will be apparent to the skilled person that within the context of the invention, the terms 'motion', 'movement' and 'displacement' may be taken as interchangeable.

In an alternative embodiment, the gas detector 10 comprises signal receiving means 33. The signal receiving means 33 in an embodiment is a known radio antenna for receiving transmitted commands from a remote transmitter. In further embodiments the signal receiving means comprises any known suitable means for receiving a transmission.

In a further embodiment, the gas detector 10 comprises a combination of user input means 30, a motion detection means 32 and a signal receiving means 33.

Optionally, the gas detector 10 comprises a display 35 allowing exposure data to be communicated to a user. This display 35 in an embodiment is an LCD screen, in further embodiments any other known suitable means of display are used. The display 35 is preferably active during the first active state and in further embodiments also active during the second inactive state.

Optionally, the gas detector 10 comprises a transmitter 40 allowing exposure data to be transmitted to an external location. The transmitter 40 in an embodiment is a known a radio transmitter. In further embodiments other known suitable means of data transmission are used. The transmission of the exposure data is configured to occur as the exposure data is calculated or at regular intervals of time so as to enable real time recording of the user's data. In further embodiments transmission of the data occurs when the gas detector 10 switches between the first active state and the second inactive state.

In use the detector 10 the processor 20 produces the exposure data from the gas sensor data in a known manner. The exposure data is written to the memory 25. When the detector is powered up, or placed in an active state in which gas is detected by the gas sensor 15, the processor is further configured to detect for the presence of an input indicating whether or not the exposure data stored in memory is to be retrieved and used in subsequent calculations. If the stored exposure data is used then a cumulative exposure to the gas is calculated using the previously stored/recorded value. Alternatively the stored value of the exposure data is ignored.

g whether or not the exposure data stored in memory is to be retrieved is derived from one or both of the user input means 30 and motion detection means 32.

In use the user may input to the detector, via the user input means 30, that the stored value is to be used. Such an input may be made be made by pressing a button, inputting via a menu etc. The user may utilise the input means 30 when utilising the detector 10 for the first time (e.g. after taking the device from another user) or whenever the situation dictates.

In use the motion detection means 32 is configured to determine if the device and therefore the user has moved to a different location. In situations where the user has moved to a different site, whilst the time taken to move to the new site may be over the reset time for the detector (e.g. 15 minutes) it may be inappropriate for the exposure to be reset. Accordingly, in such situations where motion has been detected the stored exposure detector is retrieved from the memory and subsequently used in exposure calculations.

In use the signal receiving means 33 are configured to receive a command transmitted from a remote location. A central control station may utilise the signal receiving means 33 for enabling the recording of accurate exposure data or broadcast a signal to mark the end of a work shift. Such a signal can be transmitted to multiple gas detectors 10.

The processor 20 therefore determines from the user input means and/or motion detection means 32 and/or signal receiving means 33 whether or not to use the stored value of previously calculated exposure data Based on the determination the processor that can trigger retrieval of the exposure data from the memory 25 for use in subsequent exposure calculations.

The ability of the gas detector 10 to store and retrieve exposure data across a period of deactivation longer than the reset time allows the detector 10 to more accurately determine the exposure to a target gas across a period of time that may include one or more instances of the gas detector 10 being deactivated for a period longer than the reset nore accurate data being available to the user and therefore reduces a user's risk of overexposure. Further, enabling the exposure data to be selectively retrieved from memory 25 allows the user to control whether to continue their shift with a correct exposure record or start a new exposure record if, for example, the gas detector 10 is being transferred between users. Moreover, the ability of the gas detector to determine by itself whether or not to retrieve the exposure date from memory reduces the possibility of data loss as a result of user error and reduces reliance on any supplementary hardware or control systems outside of the gas detector itself This helps ensure the reliability of the system whilst at the same time reducing costs.

Figure 2 is a flowchart of the steps performed to record exposure data according to an embodiment of the invention.

The process commences at 5101. The gas detector 10 is brought into a first state in which the gas sensor 15 is enabled.

At step S102 the gas sensor 15 detects the concentration of a target gas and processor 20 uses the data from the gas sensor 15 to calculate exposure data. Preferably as Short Term Exposure Level (STEL) and Long Term Exposure Level (LTEL) data. The detection and calculation of the exposure to the gas are performed using known methods in the art.

At step S103 the gas detector 10 is deactivated by the user and the exposure data, (S TEL and LTEL exposure data) is recorded to memory 25. In an alternative embodiment the exposure data is recorded to memory 25 during the step S102. In this deactivated state the gas sensor 15 is disabled, yet the processor 20, memory 25 and the input sensor 30/32/33 remain functional, awaiting an input received by the input sensor 30/32/33.

At step S104 the gas detector 10 receives an input via the user input means 30 or motion detection means 32 or signal receiving means 33 indicating whether the exposure data is to be carried over. In an embodiment, the gas detector 10, passively awaits an input. In an alternative embodiment, the gas detector 10 actively checks for an input. In an embodiment, the check is performed by poling the input means sensor 30/32/33. The curs during the second inactive state and in further embodiments also occurs during the first inactive state. In an embodiment, the check is configured to occur at regular intervals. In further embodiments the check occurs when the gas detector switches between the first active state and the second inactive state. It will be apparent to a skilled person that the input may be a physical user input and that input sensor 30 may comprise a physical receptor such as a touchpad or a keyboard and that user input may be made by means of a case selection from a menu or by a binary input such as a switch or button. Furthermore, such a receptor may include means for displaying feedback such as lights or a screen. This allows a user to control the retrieval the recorded STEL and LTEL exposure data. The exposure data may be retrieved if continuing a shift or not retrieved if the gas detector 10 is transferred to a new user.

If at step S104 the processor determines that the exposure data is to be used the process proceeds to step S125. If the processor determines that the exposure data is not to be used the process proceeds to step 5115.

At step S125 the recorded STEL and LTEL exposure data is retained in memory 25.

At step S126 the gas detector 10 is reactivated and the gas sensor 15 is enabled.

At step 5127 the processor 20 retrieves the recorded STEL and LTEL exposure data from memory and uses it and data from the gas sensor 15 to calculate updated STEL and LTEL exposure data.

At step S115, following a decision at step S104 not to use the exposure data, the recorded STEL and LTEL exposure data is discarded. It will be apparent to a skilled person that the data may be ignored, deleted or otherwise overwritten.

At step 5116 the gas detector 10 is reactivated and the gas sensor 15 is enabled. Steps S116 and S126 are equivalent.

s detector 15 detects the concentration of a target gas and processor 20 uses the data from the gas sensor 15 to calculate new Short Term Exposure Level (STEL) and new Long Term Exposure Level (LTEL) data.

Optionally, the gas detector 10 comprises an override step in which the exposure data stored in memory 25 is discarded after a period of time sufficient for a user's shift to have ended, regardless of an input inputted by user input means 30 or motion detection means 32 or signal receiving means 33.

In an alternative embodiment the exposure data is automatically written to the memory and the decision of whether or not to use the exposure data is made on each occasion that the detector enters an active state.

Therefore, there is provided a gas detector 10 capable of recording more accurate exposure data across a period of time that contains one or more periods over which the detector 10 is deactivated for longer than the reset time. The decision whether to carry over or discard the exposure data stored in memory is indicated by an end user input or an automated response, the latter of which enables to gas detector to self-determine whether to carry over or discard the exposure data.

Claims

Claims 1. A gas detector for measuring a response to a first target gas, the gas detector comprising a gas sensor configured to detect the presence of the first target gas, said gas sensor in communication with a processor and a memory, wherein the gas detector has: a first active state in which the gas sensor detects the concentration of a target gas, and produces a measured response for recording in the memory, and a second inactive state wherein the gas sensor does not detect the presence of the target gas, wherein the gas detector is configured to selectively switch between the two states, and the gas detector has an input sensor configured to receive at least one input, and dependant on the input received, retrieve the measured response from memory wherein the input is provided by a sensor within the gas detector, and the output of the sensor is indicative of a physical parameter associated with the gas detector.
2. The gas detector of any preceding claim wherein a measured response in memory is deleted if it is not retrieved.
3. The gas detector of any preceding claim wherein if no measured response is present in the memory, a new measured response is produced.
4. The gas detector of any preceding claim wherein a measured response is updated whilst the detector is in the first active state.
The gas detector of claim 4 wherein the measured response is an exposure value.
6. The gas detector of claim 5 wherein the exposure data is one or both of the Short Term Exposure Level (STEL) or Long Term Exposure Level (L l'EL).
7. The gas detector of claim 1 wherein the sensor detects the motion of the gas detector.
The gas detector of claim 7 wherein the sensor is a GPS device.
9. The gas detector of claim 8 wherein the GPS device signals that the measured response be retrieved from memory if motion is detected within a time period.
10. The gas detector of claim 9 wherein the motion is a displacement above a predetermined threshold.
11. The gas detector of claim 1 wherein the input is a user input.
12. The gas detector of claim 11 wherein the user input is a touch based user input.
13. The gas detector of claims 11 or 12 wherein the user input is made in response to a user prompt.
14. The gas detector of any preceding claim wherein the gas detector switches state as a result of user input.
15. The gas detector of any preceding claim wherein the exposure data is displayed to a user.
16. The gas detector of any preceding claim wherein the exposure data is transmitted to an external location.
17. A system comprising one or more detectors according to any preceding claim and further comprising a central server, wherein one or more of the detectors are configured to communicate with the central server.