Lab Scale Fermentor - Revision history

ChuckH: /* pH sensing */

2013-09-05T23:59:16Z

pH sensing

← Older revision		Revision as of 23:59, 5 September 2013
Line 68:		Line 68:
	[[File:phenol_red_OV7949.png\|300px)]]		[[File:phenol_red_OV7949.png\|300px)]]

	Alternating illumination with appropriate LEDs, using a USB webcam and a split field of view between inactive reference reflector and dye-loaded gel could work.		Alternating illumination with appropriate LEDs, using a USB webcam and a split field of view between inactive reference reflector and dye-loaded gel could work. Try [http://www.ebay.com/itm/Agarose-50-grams-Low-EEO-Molecular-Biology-Grade-DNA-RNA-Electrophoresis-1-/130944677475?pt=LH_DefaultDomain_0&hash=item1e7ce93663 agarose] for gel.

ChuckH: /* Prototype Development */

2013-09-05T23:50:15Z

Prototype Development

← Older revision		Revision as of 23:50, 5 September 2013
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	</script>		</script>
	</html>		</html>

			=== pH sensing ===

			colorimetric sensing of gel-stabilized phenol red indicator seems hopeful. The dye is readily available at low cost as a [http://www.hydropool.com/cgi-bin/hydro/item/Water-Testing/Phenol-Red-1-oz-Reagant-Refill/26242.html pool test chemical]. Differential optical absorption measurement between the violet-absorption and green-absorption peaks can be converted into a pH reading. Unfortunately the dye absorption peaks don't line up ideally with typical digital camera color filters:

			[[File:phenol_red_OV7949.png\|300px)]]

			Alternating illumination with appropriate LEDs, using a USB webcam and a split field of view between inactive reference reflector and dye-loaded gel could work.

ChuckH: /* Thermal Characterization */

2013-09-02T07:11:02Z

Thermal Characterization

← Older revision		Revision as of 07:11, 2 September 2013
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	The thermal time constant is estimated at 120 minutes, and the temperature rise rate at the "HIGH" setting corresponds to an ultimate temperature of ~80C above ambient.		The thermal time constant is estimated at 120 minutes, and the temperature rise rate at the "HIGH" setting corresponds to an ultimate temperature of ~80C above ambient.

	[[File:slowcooker_thermal_plot.png\|border\|300px]]		[[File:slowcooker_thermal_plot.png\|border\|300px]] [[File:slowcooker_thermal_plot_full.png\|border\|280px]]

	Spreadsheet: [[File:ThermalCharacterization.ods]]		Spreadsheet: [[File:ThermalCharacterization.ods]]

ChuckH: /* Thermal Characterization */

2013-09-02T07:04:51Z

Thermal Characterization

← Older revision		Revision as of 07:04, 2 September 2013
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	[[File:slowcooker_thermal_plot.png\|border\|300px]]		[[File:slowcooker_thermal_plot.png\|border\|300px]]

			Spreadsheet: [[File:ThermalCharacterization.ods]]

	{\| class="wikitable"		{\| class="wikitable"

ChuckH: /* Thermal Characterization */

2013-09-02T06:45:03Z

Thermal Characterization

← Older revision		Revision as of 06:45, 2 September 2013
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	\| TC3 \|\| Bowl, outside, near middle height		\| TC3 \|\| Bowl, outside, near middle height
	\|-		\|-
	\| TC4 \|\| Bowl, inside, ~~near~~ TC3		\| TC4 \|\| Bowl, inside, aligned with TC3
	\|-		\|-
	\| TC5 \|\| Water, ~4mm off bottom, centered		\| TC5 \|\| Water, ~4mm off bottom, centered
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	\|}		\|}

	http://~~youtu~~.be/cNEioVxZ6zs		The lid steams up at higher temperatures, might interfere with observations.

			<html>
			<script type="text/javascript" src="http://s3.www.universalsubtitles.org/embed.js">
			(
			{"video_url": "http://www.youtube.com/watch/?v=cNEioVxZ6zs"}
			)
			</script>
			</html>

ChuckH: /* Thermal Characterization */

2013-09-02T06:39:24Z

Thermal Characterization

← Older revision		Revision as of 06:39, 2 September 2013
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	\| TC6 \|\| Water, ~6mm immersed, off-center		\| TC6 \|\| Water, ~6mm immersed, off-center
	\|}		\|}

			http://youtu.be/cNEioVxZ6zs

ChuckH: /* Thermal Characterization */

2013-09-02T06:10:31Z

Thermal Characterization

← Older revision		Revision as of 06:10, 2 September 2013
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	=== Thermal Characterization ===		=== Thermal Characterization ===

	In order to establish expectations and initial control parameters for the temperature control algorithm, we measured the heating performance of the chamber filled with water. The behavior is somewhat nonlinear, and has two significant thermal masses with different thermal time constants. Nonetheless, a reasonable single-time-constant linear model approximation can be obtained.		In order to establish expectations and initial control parameters for the temperature control algorithm, we measured the heating performance of the chamber filled with water. The behavior is somewhat nonlinear, and has two significant thermal masses with different thermal time constants. Nonetheless, a reasonable single-time-constant linear model approximation can be obtained. Ambient temperature was ~30C. Initial fluid temperature was ~25C.

	The thermal time constant is estimated at 120 minutes, and the temperature rise rate at the "HIGH" setting corresponds to an ultimate temperature of ~~~110C (although that would not be achieved with water due to boiling)~~.		The thermal time constant is estimated at 120 minutes, and the temperature rise rate at the "HIGH" setting corresponds to an ultimate temperature of ~80C above ambient.

	[[File:slowcooker_thermal_plot.png\|border\|300px]]		[[File:slowcooker_thermal_plot.png\|border\|300px]]

	\|\| Thermocouple \|~~\| Location \|\|~~		{\| class="wikitable"
	\|\| TC1 \|\| Heating jacket, near heating element \|\|		\|+Thermocouple locations
	\|\| TC2 \|\| Heating jacket, center bottom \|\|		\|-
			\| TC1 \|\| Heating jacket, near heating element
			\|-
			\| TC2 \|\| Heating jacket, center bottom
			\|-
			\| TC3 \|\| Bowl, outside, near middle height
			\|-
			\| TC4 \|\| Bowl, inside, near TC3
			\|-
			\| TC5 \|\| Water, ~4mm off bottom, centered
			\|-
			\| TC6 \|\| Water, ~6mm immersed, off-center
			\|}

ChuckH: /* Prototype Development */

2013-09-02T06:02:06Z

Prototype Development

← Older revision		Revision as of 06:02, 2 September 2013
Line 25:		Line 25:

	It should be possible to control temperature with an arduino, thermistor, and solid-state relay, without any modification to the internals.		It should be possible to control temperature with an arduino, thermistor, and solid-state relay, without any modification to the internals.

			=== Thermal Characterization ===

			In order to establish expectations and initial control parameters for the temperature control algorithm, we measured the heating performance of the chamber filled with water. The behavior is somewhat nonlinear, and has two significant thermal masses with different thermal time constants. Nonetheless, a reasonable single-time-constant linear model approximation can be obtained.

			The thermal time constant is estimated at 120 minutes, and the temperature rise rate at the "HIGH" setting corresponds to an ultimate temperature of ~110C (although that would not be achieved with water due to boiling).

			[[File:slowcooker_thermal_plot.png\|border\|300px]]

			\|\| Thermocouple \|\| Location \|\|
			\|\| TC1 \|\| Heating jacket, near heating element \|\|
			\|\| TC2 \|\| Heating jacket, center bottom \|\|

ChuckH: /* Chamber */

2013-08-29T03:29:01Z

Chamber

← Older revision		Revision as of 03:29, 29 August 2013
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	[[File:slowcooker_1.jpg\|border\|250px]] [[File:slowcooker_lidgasket.jpg\|border\|200px]]		[[File:slowcooker_1.jpg\|border\|250px]] [[File:slowcooker_lidgasket.jpg\|border\|200px]]
	----		----
	The lid is made of glass. It appears ''not'' to be tempered, as the handle is attached by a screw through a drilled hole. This is good, because it means we can drill our own holes for stirring, sensors, and fluid lines. I will try using some cheap diamond core drills ~~The~~ set shown cost $5 on Amazon).		The lid is made of glass. It appears ''not'' to be tempered, as the handle is attached by a screw through a drilled hole. This is good, because it means we can drill our own holes for stirring, sensors, and fluid lines. I will try using some cheap diamond core drills (the set shown cost $5 on Amazon).

	[[File:slowcooker_lid_holes.jpg\|border\|300px]]		[[File:slowcooker_lid_holes.jpg\|border\|300px]]

ChuckH at 03:07, 29 August 2013

2013-08-29T03:07:27Z

← Older revision		Revision as of 03:07, 29 August 2013
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	~~[[PageOutline]]~~

	= Lab Scale Fermentor =		= Lab Scale Fermentor =

	This is a version of the ~~OSE~~ [[Fermentor]] primarily for process-development experiments.		This is a version of the [[Fermentor#System_Engineering_Breakdown_Diagram\|OSE Fermentor]] primarily for process-development experiments.

	It may be used on the [[Polylactic acid]] project.		It may be used on the [[Polylactic acid]] project.