US-20260126367-A1 - MODULAR OPTICAL PARTICLE COUNTER SENSOR AND APPARATUS

US20260126367A1US 20260126367 A1US20260126367 A1US 20260126367A1US-20260126367-A1

Abstract

A modular optical particle counter sensor and apparatus are described that consolidates counting functionality on a single main counter board and has expandable functionality through connections to plug-in system boards. The modular optical particle sensor may be directly connected to a manifold with an integrated venturi for better controlling the flow rate of the air stream passing through the apparatus for sampling.

Inventors

David Pariseau
Adam Giandomenico

Assignees

PARTICLES PLUS, INC.

Dates

Publication Date: 20260507
Application Date: 20251003

Claims (20)

1 . A method of operating a remotely controlled optical particle counter comprising: generating particle count data with an optical particle counting device within a compact housing wherein the optical particle counter includes a light source that illuminates a gas flow containing particles to be counted and wherein the gas flow is conducted through a venturi, a light detector, and a controller that controls device operation wherein the controller is communicatively connected to a display within the compact housing, the controller being configured to operate a programmable status device having stored settings corresponding to a plurality operational modes of the optical particle counter; controlling operating parameters of the optical particle counting device using a remote computing device connected to the optical particle counting device with a communication network; and selecting an operational mode from the plurality of operational modes to perform a particle counting operation wherein the programmable status device records the operating parameters controlled with the remote computing device.
2 . The method of claim 1 further comprising: conducting the gas flow through a flow channel manifold that includes the venturi; operating a flow actuator to control a flow rate of the particle flow wherein the controller is connected to a memory and a communication port connected to the communication network, and wherein the controller operates a communication interface that transmits operational state data for the optical particle counter regarding an operational mode to the remote computing device.
3 . The method of claim 1 further comprising: operating a signal processing circuit to process detected signals above a threshold for at least one output channel of the optical particle counting device, an analog to digital converter that converts analog signals above the threshold to digital signals to generate particle count data.
4 . The method of claim 3 further comprising: operating a core module circuit board assembly on which the signal processing circuit and the controller are mounted, the core module circuit board assembly further comprising at least one connector to electrically connect the controller to an attachable circuit board.
5 . The method of claim 4 wherein the attachable circuit board is configured to control at least one of a power level and a sampling parameter of the optical particle counter.
6 . The method of claim 2 wherein the flow channel manifold further comprises an output for the venturi that is connected to an input to a sensor chamber wherein the light beam traverses the sensor chamber and the flow actuator comprises a pump, the manifold further including a connector that directly connects the venturi to a filter at a pump entry and a flow sensor.
7 . The method of claim 3 wherein operating the signal processing circuit further comprises a step for controlling pulse threshold settings for an analog front end signal processing circuit comprising a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).
8 . The method of claim 7 wherein the field programmable gate array (FPGA) is connected to the controller such that the FPGA controls setting of pulse thresholds with one or more pulse width modulators (PWM).
9 . The method of claim 7 wherein an FPGA is mounted to a core module circuit board on which the controller, an analog front end circuit, an analog to digital converter and a power control circuit are mounted.
10 . The method of claim 1 further comprising: connecting an attachable circuit board to a circuit board connector on the optical particle counting device wherein the attachable circuit board comprises the display and a battery mounted in the compact housing.
11 . The method of claim 10 wherein the attachable circuit board comprises a universal serial bus (USB) connection.
12 . The method of claim 10 wherein the attachable circuit board comprises an environmental sensor.
13 . The method of claim 10 wherein the attachable circuit board further comprises a wireless transceiver.
14 . A remotely controlled optical particle counter comprising: an optical particle counting device within a compact housing wherein the optical particle counter device includes a light source that illuminates a gas flow containing particles to be counted and wherein the gas flow is conducted through a venturi, a light detector, and a controller that controls device operation wherein the controller is communicatively connected to a display within the compact housing, the controller being configured to operate a programmable status device having stored settings corresponding a plurality operational modes of the optical particle counting device; and wherein the optical particle counting device is configured to communication with a remote computing device connected to the optical particle counting device with a communication network for controlling operating parameters of the optical particle counting device, such that a selected operational mode performs a particle counting operation wherein the programmable status device records the operating parameters controlled with the remote computing device.
15 . The optical particle counter of claim 14 further comprising: a flow channel manifold that includes the venturi; and a flow actuator to control a flow rate of the particle flow wherein the controller is connected to a memory and a communication port connected to the communication network, and wherein the controller operates a communication interface that transmits operational state data for the optical particle counter regarding an operational mode to the remote computing device.
16 . The optical particle counter of claim 14 further comprising: a signal processing circuit to process detected signals above a threshold for at least one output channel of the optical particle counting device; and an analog to digital converter that converts analog signals above the threshold to digital signals to generate particle count data.
17 . The optical particle counter of claim 16 further comprising: a core module circuit board assembly on which the signal processing circuit and the controller are mounted, the core module circuit board assembly further comprising at least one connector to electrically connect the controller to an attachable circuit board.
18 . The optical particle counter of claim 14 wherein an attachable circuit board is configured to control at least one of a power level and a sampling parameter of the optical particle counter.
19 . The optical particle counter of claim 15 wherein the flow channel manifold further comprises an output for the venturi that is connected to an input to a sensor chamber wherein the light beam traverses the sensor chamber and the flow actuator comprises a pump, the manifold further including a connector that directly connects the venturi to a filter at a pump entry and a flow sensor.
20 . The optical particle counter of claim 16 wherein the signal processing circuit further comprises stored pulse threshold settings for an analog front end signal processing circuit comprising a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

Description

RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 18/650,437, filed Apr. 30, 2024, entitled “Modular Optical Particle Counter Sensor and Apparatus”, now U.S. Pat. No. 12,436,084 , which is a continuation of U.S. patent application Ser. No. 17/139,625, filed Dec. 31, 2020, which claims priority to U.S. Provisional Ser. No. 63/061,761 , filed on Aug. 5, 2020, and also claims priority to United States Provisional Ser. No. 63/047,230 , filed Jul. 1, 2020, the contents of the above applications being incorporated herein by reference in their entirety. BACKGROUND Optical Particle counters (OPC) used in air quality applications can provide an indication of particulate levels in a variety of ways. They can be used to provide absolute counts by channel size, or to provide estimated particulate concentrations by size, or even to estimate particle mass within some size range. Particle counters were initially designed and used in manufacturing applications to help ensure a minimum desired air quality for critical manufacturing operations. Particle counters are also increasingly being used in commercial and residential air quality monitoring to provide information about airborne particulates. This information can be used by occupants to make decisions about changing their environment should these levels increase beyond some desired threshold. Changing the environment might entail engaging air filtration equipment, or reducing/excluding external air sources temporarily during an event, etc. Airborne particulates can be caused by many factors, some particulates are naturally occurring (pollen and other allergens) while some are man-made (manufacturing, construction, combustion, etc.). Optical particle counters (either a light-blocking or light-scattering) detect particulates passing through a light beam and generate a corresponding signal representing the detected particle, with some characteristic (typically amplitude) of that signal being related to the particulate's size. Typically these pulses are grouped in “size bins” with each bin corresponding to the number of particulates in a specific size range seen over some (usually user-specified) sample period. An instrument with more “size bins” or channels provides increased performance in that it allows for a more detailed particulate size distribution to be collected. A more detailed size distribution more accurately describes the make-up of particles by size in an environment. This has particular benefit when using an OPC to estimate mass in that in order to estimate mass with an OPC one has to calculate the volume of each particle channel. An average size for the channel is determined and then the volume for a particle of that size is calculated. The volume of a sphere can be calculated by 4/3πr3 . Since the radius is cubed it is highly influenced by the average size chosen. So, an OPC with more channels (to a limit) can provide more of a granular size distribution and thus can better estimate the mass for each individual channel. Typically these are then added to provide a mass estimate for particulates below some threshold size (e.g. PM 2.5 would provide the estimated mass of all particulates below 2.5 um). SUMMARY OF THE INVENTION The devices and methods described herein pertain to optical particle counting in an airflow of particles is formed and passed through a beam of light wherein a light detector detects light scattered by the particles as they pass through a beam, or alternatively, detects the shadows created by the particles as they pass through the beam. One or more circuit boards have circuit components mounted thereon that serve to process the detected light signals to count the number of particles and can detect further characteristics of the particles such as size and mass, for example. The circuitry can be configured to process and record particulate data in a variety of different configurations where a core module performs basic functions and one or more additional circuit boards can be attached to the core module so that a particle counting system can be constructed as needed by different users. The system can be configured for hand carried portable particle counting or for fixed position operation within a specific facility, for example. A system can be controlled locally by a single user, or within a local area network, or entirely remotely using a public communication network with wired and/or wireless communication. Preferred configurations are assembled into a compact housing in which the core module is contained with one or more additional circuit modules attached to connectors on a single core module circuit board assembly. The flow path within the compact housing can be configured with the circuitry to reduce the volume and weight of the system relative to prior art systems that cannot be adapted to a large variety of operating modes and capabilities. A flow channel manifold includes a venturi to pro