Continuous flow moisture analyzer

• US 6,675,636 B2
• Filed: 05/12/2003
• Issued: 01/13/2004
• Est. Priority Date: 10/20/2000
• Status: Expired due to Term

• Current Assignee: Ametek Incorporated
• Original Assignee: Arizona Instrument LLC
• Inventors: Sadler, William G.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): Frank, Rodney
• Application Number:
  US10/436,927
• Publication Number:
  US 20030200797A1
• Time in Patent Office: 246 Days
• Field of Search: 73/73, 73/76, 73/290.1, 73/190.1, 73/290.3, 73/290.4
• US Class Current: 73/73
• CPC Class Codes: G01N 1/40 Concentrating samples
• CPC Class Codes: G01N 2001/4027 evaporation leaving a concentrated sample
• CPC Class Codes: G01N 25/56 by investigating moisture content

Abstract

A continuous flow moisture analyzer (20) includes a coaxial needle (34) having first and second needle portions (36, 38). The first needle portion (36) receives a carrier gas (24) and expels the carrier gas (24) through an output orifice (60). The second needle portion (38) has an input orifice (62) for receiving the carrier gas (24) expelled from the output orifice (60). A housing (40) encloses the output orifice (60) and the input orifice (62) when the moisture analyzer (20) is in a standby mode to obtain a baseline moisture content of the carrier gas (24) within the moisture analyzer (20). A bottle (48) retains a sample material (50). When the analyzer (20) is in an active mode, the coaxial needle (34) penetrates a septum (52) of the bottle (48) to position the output and input orifices (60, 62) in the bottle (48). The carrier gas (24), expelled from the output orifice (60), absorbs moisture from the sample material (50) in the bottle (48). The expelled carrier gas (24) carrying the moisture is received at the input orifice (62) and is transported through the second needle portion (38) to a moisture sensor (70) which detects the moisture in the carrier gas (24).

Claims

1. A method for measuring moisture in a sample, the method comprising:

flowing a carrier gas through a sealed flow path in a standby mode to remove moisture from the flow path other than a baseline moisture of the carrier gas, wherein the flow path includes an input channel in communication with an output channel;

measuring the baseline moisture of the carrier gas flowing through the flow path in the standby mode;

then introducing the sample into the flow path in an active mode while continuing to flow the carrier gas through the flow path and while preventing the entry of uncontrolled moisture into the flow path;

measuring the moisture content of the carrier gas in the active mode; and

determining the moisture content in the sample using the baseline moisture measured in the standby mode and the moisture content measured in the active mode.

2. The method of claim 1 wherein:

the input channel includes an output orifice in communication with an input orifice of the ouput channel;

the flow path includes a sealed chamber that in the standby mode is in fluid isolation from the sample and encloses the output orifice and the input orifice; and

flowing the carrier gas through the flow path in the standby mode includes flowing the carrier gas out of the output orifice, into the sealed chamber and into the input orifice.

3. The method of claim 2 wherein introducing the sample into the carrier gas flow path comprises inserting the output orifice and the input orifice from the sealed chamber into a sealed container holding the sample while preventing the entry of uncontrolled moisture into the fluid flow path.

4. The method of claim 1 further comprising heating the sample in the active mode.

5. The method of claim 1 wherein flowing the carrier gas through the flow path in the standby mode and continuing to flow the carrier gas through the flow path in the active mode include flowing the carrier gas at a predetermined flow rate.

6. The method of claim 1 wherein measuring the baseline moisture of the carrier gas flowing through the flow path in the standby mode and measuring the moisture content of the carrier gas in the active mode comprise measuring the moisture using a moisture sensor.

7. The method of claim 6 wherein determining the moisture content in the sample using the baseline moisture measured in the standby mode and the moisture content measured in the active mode comprises using a processor to compute a difference between the moisture content and the baseline moisture to obtain a moisture figure for the sample material.

8. The method of claim 1 wherein the sample is enclosed in the interior of a sealed container and introducing the sample into the flow path in the active mode comprises including the interior of the sealed container in the flow path without introducing uncontrolled moisture into the flow path.

9. A continuous flow moisture analyzer for measuring moisture in a sample, the analyzer comprising:

a flow path having an input channel adapted to receive a carrier gas, the input channel being in communication with an output channel;

a moisture sensor in communication with the output channel and adapted to measure a moisture content of the carrier gas;

a sample container adapted to hold the sample in fluid isolation from the flow path in a standby mode wherein the carrier gas flows through the flow path and removes moisture from the flow path; and

a transport mechanism adapted to place the sample container in fluid communication with the flow path in an active mode while preventing the entry of uncontrolled moisture into the flow path.

10. The continuous flow analyzer of claim 9 further comprising means for determining the moisture content in the sample from the moisture content measured in the active mode and the baseline moisture content measured in the standby mode.

11. The continuous flow analyzer of claim 9 wherein:

the input channel includes an output orifice in communication with an input orifice of the ouput channel; and

the flow path includes a sealed enclosure that in the standby mode is in fluid isolation from the sample container and encloses the output orifice and the input orifice.

12. The continuous flow moisture analyzer of claim 9 further comprising a heater for heating the sample in the active mode.

13. The continuous flow moisture analyzer of claim 9 further comprising a mass flow sensor in fluid communication with the flow path for measuring a flow rate of the carrier gas.

14. The continuous flow moisture analyzer of claim 10 wherein the means for determining the moisture content in the sample comprises a processor configured to compute a baseline moisture content of the carrier gas in the standby mode, to compute a moisture content of the carrier gas in the active mode and to compute a difference between the moisture content and the baseline moisture content to obtain a moisture figure for the sample material.

15. A continuous flow moisture analyzer for measuring moisture in a sample, the analyzer comprising:

a carrier gas flow path including an input channel for introducing a flow of carrier gas and an output channel for the exit of the flow of carrier gas;

a sealed enclosure for placing the input channel in communication with the output channel when the analyzer is in a standby mode; and

means for introducing the sample into the carrier gas flow path while continuing to flow the carrier gas through the flow path and while preventing the entry of uncontrolled moisture into the fluid flow path.

16. The continuous flow moisture analyzer of claim 15 further comprising a mass flow sensor in fluid communication with the flow path for measuring a flow rate of the carrier gas.

17. The continuous flow moisture analyzer of claim 16 wherein:

the moisture sensor is a relative humidity sensor; and

the analyzer further comprises a processor in communication with each of the relative humidity sensor and the mass flow sensor for computing a moisture content of the carrier gas with respect to a unit of time.

18. The continuous flow moisture analyzer of claim 15 wherein:

the input channel includes an output orifice for expelling the carrier gas from the input channel;

the output channel includes an input orifice for receiving the carrier gas expelled from the output orifice; and

the sealed enclosure is in fluid isolation from the sample and encloses the output orifice and the input orifice when the analyzer is in the standby mode.

19. The continuous flow moisture analyzer of claim 15 wherein:

the input channel and the output channel form a coaxial needle having a first end and a second end, the output orifice and the input orifice being located proximate the coaxial needle second end; and

the sealed enclosure comprises a sleeve having a first side and a second side, the coaxial needle extending through a first opening in the first side, and the second end of the coaxial needle blocking a second opening in the second side of the sleeve to form a sealed chamber within the sleeve in which the output orifice and the input orifice reside in the standby mode.

20. The continuous flow moisture analyzer of claim 15 wherein:

the means for introducing the sample into the carrier gas flow comprises a sample container for retaining the sample;

the container being configured to abut the sleeve when the moisture analyzer is in an active mode, the container having a septum facing the sleeve; and

the container further being configured so that when the container abuts the sleeve, the sleeve retracts to allow the coaxial needle to penetrate the septum to position the output and input orifices in the bottle, whereby the carrier gas expelled from the output orifice can absorb moisture from the sample material.