# US 2019/0170691 A1 · Low power photoionization detector (pid)

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- Number: US 2019/0170691 A1
- Document ID: US20190170691A1
- Status: Published application
- Kind: A1
- Application number: 16/323,862
- Filed: 2016-08-09
- Published: 2019-06-06
- Earliest claimed: 2016-08-09
- Assignees: Honeywell International Inc.
- Applicants: Honeywell International Inc.
- Inventors: Peter HSI; Wei YEH; Dan ZHANG; Yuhui XU; Kui LU
- Web page: https://patentgrep.com/patent/US20190170691A1

## CPC

- G01N 27/64: using wave or particle radiation to ionise a gas, e.g. in an ionisation chamber
- H01J 27/24: using photo-ionisation, e.g. using laser beam
- H01J 49/161: {using photoionisation, e.g. by laser}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A photoionization detector is disclosed. The photoionization detector comprises a detector electrode that outputs a signal, an ultraviolet lamp, a lamp driver communicatively coupled to the ultraviolet lamp and configured to turn the ultraviolet lamp on and off in response to a control input, and a controller that is communicatively coupled to the output signal of the detector electrode and to the control input of the lamp driver, that outputs an indication of gas detection based on the output signal of the detector electrode, and that turns the lamp driver on and off with an on duty cycle of less than 10%.

## Claims

### Claim at position 1

-15. (canceled)

### Claim 16

A photoionization detector, comprising:
a detector electrode that outputs a signal;
an ultraviolet lamp;
a lamp driver communicatively coupled to the ultraviolet lamp and configured to turn the ultraviolet lamp on and off in response to a control input; and
a controller that is communicatively coupled to the output signal of the detector electrode and to the control input of the lamp driver, that outputs an indication of gas detection based on the output signal of the detector electrode, and that turns the lamp driver on and off with an on duty cycle of less than 10%.

### Claim 17 (depends on 16)

The photoionization detector of claim 16, wherein the controller turns the lamp driver on and off with an on duty cycle of less than 2%.

### Claim 18 (depends on 16)

The photoionization detector of claim 16, further comprising a filter having a time constant of less than 5 milliseconds (mS), where the filter receives the signal output by the detector electrode and outputs a filtered detector electrode signal, wherein the controller is communicatively coupled to the output signal of the detector electrode via the filter and outputs the indication of gas detection based on the filtered detector electrode signal output by the filter.

### Claim 19 (depends on 18)

The photoionization detector of claim 18, further comprising an analog-to-digital converter that outputs a digital filtered detector electrode signal, wherein the controller is communicatively coupled to the filtered detector electrode signal via the analog-to-digital converter and outputs the indication of gas detection based on the digital filtered detector electrode signal output by the analog-to-digital converter, and wherein the controller turns the analog-to-digital converter on and off to achieve an on duty cycle of less than 1% and wherein the controller turns the analog-to-digital converter on when the lamp driver is turned off and turns the analog-to-digital converter off before the lamp driver is next turned on.

### Claim 20 (depends on 19)

The photoionization detector of claim 19, wherein the controller turns the analog-to-digital converter on for less than 15 microseconds (μS).

### Claim 21 (depends on 20)

The photoionization detector of claim 20, wherein the controller turns the analog-to-digital converter on a predefined period of time after the lamp driver is turned off, where the predefined period of time is at least equal to the time constant of the filter.

### Claim 22 (depends on 18)

The photoionization detector of claim 18, wherein the filter comprises an electronic amplifier.

### Claim 23 (depends on 16)

The photoionization detector of claim 16, further comprising a battery that provides electrical power to the lamp driver and to the controller.

### Claim 24 (depends on 16)

The photoionization detector of claim 16, wherein the photoionization detector is operable to detect a presence of volatile organic compounds (VOCs).

### Claim 25

A method of detecting presence of gas with a photoionization detector (PID), comprising:
turning an ultraviolet lamp on and off periodically by a controller, where the on duty cycle is less than 10%;
while the ultraviolet lamp is turned off, sampling an output of a detector electrode;
analyzing by the controller the sampling of the output of the detector electrode; and
outputting a gas detection indication by the controller based on the analysis of the sampling of the output of the detector electrode.

### Claim 26 (depends on 25)

The method of claim 25, further comprising filtering the output of the detector electrode by a filter having a time constant of less than 50 milliseconds (mS), wherein the filtered output of the detector electrode is sampled and provided to the controller for analyzing.

### Claim 27 (depends on 26)

The method of claim 26, wherein the sampling is enabled by the controller with a duty cycle that is less than 1%.

### Claim 28 (depends on 26)

The method of claim 26, wherein the sampling is enabled by the controller for less than 15 microseconds (μS).

### Claim 29 (depends on 26)

The method of claim 26, wherein the sampling comprises analog-to-digital conversion.

### Claim 30 (depends on 25)

The method of claim 25, wherein the on duty cycle of the ultraviolet lamp is less than 2%.

### Claim 31 (depends on 25)

The method of claim 25, further comprising presenting an alert of presence of detected gas by a personal portable photoionization detector based on the gas detection indication output by the controller, wherein the personal portable photoionization detector comprises the ultraviolet lamp, the detector electrode, and the controller.

### Claim 32

A photoionization detector, comprising:
a detector electrode that outputs a signal;
an ultraviolet lamp;
a lamp driver communicatively coupled to the ultraviolet lamp and configured to turn the ultraviolet lamp on and off in response to a control input;
a filter that receives the signal output by the detector electrode and outputs a filtered detector electrode signal, where the filter has a time constant of less than 50 milliseconds (mS); and
a controller that is communicatively coupled to the filtered detector signal output by the filter and to the control input of the lamp driver, that outputs an indication of gas detection based on the filtered detector electrode signal output by the filter, and that turns the lamp driver on and off.

### Claim 33 (depends on 32)

The photoionization detector of claim 32, wherein the filter has a time constant of less than 5 mS.

### Claim 34 (depends on 32)

The photoionization detector of claim 32, wherein the controller turns the lamp driver on and off to achieve an on duty cycle of less than 10%.

### Claim 35 (depends on 34)

The photoionization detector of claim 34, further comprising an analog-to-digital converter that is coupled to the filter and to the controller, that converts the filtered detector electrode signal from the filter to a digital filtered detector electrode signal, and that outputs the digital filtered detector electrode signal to the controller, wherein the controller outputs the indication of gas detection based on the digital filtered detector electrode signal output by the analog-to-digital converter and wherein the controller turns the analog-to-digital converter on and off to achieve an on duty cycle of less than 1% and wherein the controller turns the analog-to-digital converter on when the lamp driver is turned off and turns the analog-to-digital converter off before the lamp driver is next turned on.