Operating Procedures for the Main Testing Instruments in a Feed Laboratory
Operating Procedures for the Main Testing Instruments in a Feed Laboratory
Operating Procedures for the 722 Visible Spectrophotometer
1.
Turn on the power and preheat for 20 minutes.
2.
Adjust to the required wavelength. (Turn the wavelength adjustment knob.)
3.
Zero adjustment (0%T)
Place the light-blocking body into the sample holder and pull the sample holder rod so that it enters the light path. Then press the "0%T" button on the instrument to complete the zero adjustment.
4. 100% adjustment
Place the blank sample into the sample holder (put the background into the first hole of the colorimetric holder, and the sample cover must be closed), and pull the sample holder rod so that it enters the light path. Then press 100%T on the instrument; when "BL" appears on the screen, the 100% adjustment is complete. (When adjusted to 100%, it displays 0.000 in absorbance mode and 100.0 in transmittance mode.)
5. Measurement
Press the "Function" key to switch to measurement mode, close the sample compartment cover, and the meter displays 0.000. Then pull the sample holder so that the test sample enters the test path position; the currently displayed data is the value of the sample being tested.
Prepared by:
December 30, 2008
Operating Procedures for the TG328A Optical Analytical Balance 1.
Calibrate the balance to a level position, and set all mechanical weights to zero.
2.
Connect the power supply and preheat for 30 minutes.
3.
Gently open the side door and weigh the sample. The sample must not be placed directly on the balance pan. Accurate to one ten-thousandth of a gram, weighing range 0~199.990 g.
4.
When weighing an object, the weights must be selected in order "from large to small," that is, starting with a weight approximately equal to the mass of the object being weighed, gradually increasing the weights from large to small, adding or removing weights according to the direction of the pointer deviation, until the reference line appears on the projection screen and the reading stops within 10 milligrams.
5.
After weighing is completed, remove the object being weighed, and set all mechanical weight dials to zero. Close the balance doors properly, cut off the power supply, and put on the dust cover.
Prepared by:
Year Month Day
Operating Procedures for the SK-95-10 Box-Type Resistance Furnace 1.
Connect the resistance furnace and the controller, and connect the power supply.
2.
A new resistance furnace should be preheated for about 20 hours as specified.
3.
When in use, adjust the controller temperature according to the sample requirements.
4.
Place the sample into the furnace chamber, close the furnace door properly, and begin heating.
5.
After the specified temperature is reached, start timing; when the required time is up, turn off the power.
6.
Open the furnace door a crack and wait 30 minutes before opening the door to take out the sample.
Prepared by:
Year Month Day
Operating Procedures for the 101-0 Electric Thermostatic Drying Oven 1.
Set the blower switch to the off state, set the temperature to the low-temperature state, and connect the power supply.
2.
Press the set button to set the required temperature, then press the set button again to return to measurement state.
3.
Insert a thermometer above the ventilation hole, and use the temperature at this point as the actual temperature.
4.
Place the sample in for drying and adjust according to the required time; do not open the door during this period.
5.
After drying, take out the sample and turn off the power.
Prepared by:
Year Month Day
--------------------------------------
Concise language, thank you for your guidance!
--------------------------------------
The optical analytical balance is too troublesome; I don't know how to use it.
--------------------------------------
Operating Procedures for the Sample Grinder
(1) Place the grinder on a flat tabletop.
(2) Before use, check whether the power supply and the grinder are normal, and whether there is residual sample from the previous use inside the grinder.
(3) Check whether the grinder screen is of the required specification.
(4) The grinder should be started before placing the sample from the hopper into the grinder.
(5) After the sample is ground, wait until the grinder stops rotating before cleaning out the sample.
(6) It is strictly forbidden to start the grinder without closing the grinder door.
Operating Procedures for the Electronic Analytical Balance
(1) Checks before use:
1. Check whether the balance is level and whether the balance pan is clean. If there is dust, brush it clean with a soft-bristle brush.
2. Check whether the silica gel desiccant in the balance chamber has changed color. If it has changed color, replace the desiccant.
(2) Calibration of the balance:
The balance must be powered on for 60 minutes to obtain a stable working temperature. After it stabilizes, when pressing the "T" key displays "0.0000 g," press and hold the "C" key; when "CAL" is displayed, place the calibration weight in the center of the weighing pan, and at the same time close the glass door of the draft shield. Wait for the balance to calibrate automatically internally. When the display shows the nominal value of the calibration weight and the buzzer sounds once, calibration of the balance is complete.
(3) Operating steps
1. Power on: Leave the balance unloaded and press the "on" key once. The balance displays a self-test (all segments flash, etc.). When the balance stabilizes and is calibrated, weighing can begin.
2. Power off: Press and hold the "off" key until "OFF" appears on the display. Release the key.
3. Simple weighing: When the balance displays "0.0000," place the sample on the weighing pan and close the glass door of the balance draft shield. Wait for the balance to stabilize and display the unit "g," then read the weighing result.
(4) Precautions:
1. The analytical balance should be placed on a firm bench in a room with uniform temperature, avoiding vibration, moisture, direct sunlight, and protection from corrosive gases.
2. Check whether the balance is intact before and after weighing, and keep the balance clean. During weighing, close the balance doors as you go.
3. The load on the balance should not exceed the maximum capacity, and items should be placed in the center of the pan.
4. Chemical reagents and samples must be weighed in appropriate containers, such as weighing bottles, watch glasses, or glassine paper, etc., and must not be placed directly on the balance pan for weighing.
5. The balance should be calibrated before first use, for regular weighing service, and when its placement position is changed. Calibration weights should be stored properly.
Operating Procedures for the Spectrophotometer
(1) Installation and adjustment of the instrument
1. The spectrophotometer is a precision instrument made using the photoelectric principle, used for qualitative or quantitative analysis by measuring the optical density or absorbance of a solution. The specified principles must be followed during use.
2. The instrument must be installed in a clean and dry room, with a working temperature of 5-35°C.
3. Avoid vibration; it should be placed on a stable workbench during use.
4. Avoid direct sunlight.
5. Keep away from high-intensity magnetic fields, electric fields, and electrical equipment that generates high-frequency waves, and keep away from places with corrosive gases such as hydrogen sulfide, sulfurous acid, and fluorine.
6. Power supply: (220±22) V; (50±1) Hz, and a grounding wire must be installed.
(2) Use and maintenance of the instrument
1. Turn on the power and preheat for 30 minutes.
2. Place the blank into the first cell as the reference, and use the others as sample cells.
3. Adjust '0' and full scale, then pull the sample cell holder rod in sequence. After the pointer stabilizes, read the absorbance A value directly. Each time an 'A' value is read, '0' and full scale must be adjusted once, and the reading should be taken quickly to prevent inaccurate readings caused by excessive time.
4. Do not touch the light-transmitting sides of the cuvette with your hands; keep them clean, transparent, and free of dirt and water droplets.
5. The liquid in the cuvette should be free of bubbles, and must not splash outside into the dark chamber of the spectrophotometer, to prevent corrosion damage and to prevent the solution, after evaporation and vaporization, from filling the light path of the sample chamber and causing measurement errors.
6. After measurement is completed, fully clean the cuvette and let it dry for later use. Place silica gel desiccant in the dark chamber of the spectrophotometer to prevent the lamp chamber from becoming damp and the reflector from becoming moldy or contaminated.
7. The moisture-proof silica gel in the drying cylinder should remain blue. If it turns red, take it out and replace it to prevent the instrument from becoming damp.
8. After each use, cover the instrument promptly and place several bags of silica gel desiccant inside.
9. Keep the area around the instrument clean and tidy, with no clutter.
Fat Extraction Apparatus
(1) The Soxhlet extractor is formed by connecting three parts: the extraction tube, the extraction flask, and the condenser. The extraction tube has a siphon tube and a vent tube on both sides. The filter paper packet containing the sample is placed in the extraction tube, and the solvent is added to the extraction flask. When heated, the solvent vapor passes through the vent tube to the condenser, and the condensed solvent drips into the extraction tube to extract the sample.
(2) When the solvent level in the extraction tube exceeds the height of the siphon tube, the solvent containing fat in the extraction tube flows through the siphon tube into the extraction flask. After repeated extraction in this way, the fat in the sample gradually becomes fully concentrated in the extraction flask. After extraction is completed, the fat content of the sample is calculated from the decrease in weight of the sample filter paper packet before and after defatting. Since the organic solvent extracts not only fat from the sample but also other fat-soluble components, the result measured in this experiment should be the crude fat content.
(3) Precautions
When drying the filter paper packet in the oven to remove solvent, to prevent ether vapor from burning and catching fire, the oven door should first be opened halfway.
Operating Procedures for the Vacuum Pump
Use and precautions
1. First unscrew the oil filler plug, add oil through the oil filler hole up to 2/3 of the oil mark, then add a small amount of pump oil through the intake port to lubricate the pump chamber, to avoid seizing and overheating after startup. Use No. 1 vacuum pump oil, or imported light high-grade engine oil for cars may also be used as a substitute.
2. Connect the power cord as specified (for a three-phase motor, note that the motor rotation direction should be consistent with the arrow direction on the pump bracket). Remove the rubber plug cap on the exhaust pipe, run it idly for a moment, and then begin normal operation.
3. The pipeline connected to the pump intake port should not be too long. Be sure to check the external connecting pipeline, joints, and container of the vacuum pump; they must absolutely not leak and must be sealed. Otherwise, the ultimate vacuum and the service life of the vacuum pump will be affected.
4. Working environment of the pump: operate within a temperature range of 5°C-40°C, with relative humidity not greater than 85%, and intake pressure less than 1.3*1000. For vacuum pumps with a pumping speed above 0.5 L/s, a gas ballast valve is installed. If the relative humidity is relatively high, the gas ballast valve can be opened for purification, so as to purify the pump oil and extend the service time of the pump oil; close it promptly after purification is completed.
5. The suction port of this pump must not be continuously open to the atmosphere for more than 3 minutes.
6. This pump is a high-precision product, and it is not a corrosion-resistant vacuum pump. It is recommended to use it with a filter. It cannot work under any of the following conditions:
(1) It must not suction gases containing particles or dust, or colloidal, watery, liquid, or corrosive substances.
(2) It must not suction explosive gases or gases with excessively high oxygen content.
(3) It must not operate under long-term pumping with system leakage or with a container matched to the vacuum pump that is too large.
(4) It must not be used as a gas transfer pump, compression pump, etc.
Operating Procedures for the Constant-Temperature Water Bath
(1) Instructions for use
1. Before energizing, first add an appropriate amount of water to the water tank; distilled water is best. Never run without water or with the water level below the electric heating tube, to prevent the electric heating tube from bursting and being damaged.
2. The temperature control system of this instrument uses a TDA-8002 pointer-type temperature controller. During use, connect the power supply; the green light comes on, the instrument begins to work, and the heater begins heating. Then, according to the temperature you need, turn the temperature setting knob. When the green light is on, it indicates heating; when the red light is on, heating stops and the heater stops heating. When the red and green lights alternate flashing, it indicates entry into the constant-temperature state. If you want to change the temperature, turn the temperature setting knob at any time. During use, the temperature indication displayed by the temperature controller is the actual required temperature.
(2) Precautions
1. When the water bath is in use, it must be reliably grounded, and water must not overflow into the control box, so as to avoid danger.
2. It must be used with the specified power supply - 220V. Never connect it to a 380V power supply, otherwise the equipment will be damaged.
Equipment damaged.
Operating Procedures for the Constant-Temperature Drying Oven
(1) Operating method
1. Connect the power supply.
2. Adjust the temperature controller to the required temperature.
3. When the temperature indication reaches the set value, place in the item to be tested.
4. Once measurement begins, opening the oven door should be avoided.
(2) Calibration method
1. Calibrate by comparing a 150°C thermometer with the temperature controller.
2. When the oven temperature reaches the set temperature, place the 150°C thermometer inside.
3. Time for 60 minutes; when the temperature reaches a stable state, read the temperature value.
4. Repeat steps 2 and 3 to calibrate at least three times.
(3) Maintenance and care
1. Keep the inside and outside of the oven clean at all times.
2. Ventilate regularly to remove moisture.
(IV) Precautions
1. Avoid putting in strong acids, alkalis or corrosive substances.
2. If the oil liquefies, it should be placed on a tray, so that oil adhering to the outside of the bottle does not drip into the chamber.
Operating procedures for the high-temperature furnace
(I) Instructions for use
1. The high-temperature electric furnace is a high-temperature heating device with a temperature controller; it is lined inside and out with refractory material, in the middle are silicon carbide rods or nickel-chromium resistance wires serving as the heat source, and inside the high-temperature chamber there is a thermocouple connected to the temperature controller to control the furnace temperature.
2. The high-temperature furnace should be placed on a sturdy, stable bench; do not place flammable or explosive items around the furnace; when in use, the furnace chamber should be lined with clean refractory bricks to prevent the heated object from sticking to the furnace chamber.
3. When the electric furnace is used for the first time, or used again after being out of service for a long time, it must be dried out. Drying time: 4 hours at room temperature 20°C, 4 hours at 200-600°C. When in use, the furnace temperature must not exceed the maximum temperature, so as not to burn out the electric heating elements. It is also forbidden to pour various liquids or molten metal into the furnace.
4. After ignition is complete, first cut off the power supply, then open the furnace door halfway and let it cool slightly before fully opening the furnace door; this prevents the furnace chamber from cracking due to sudden cooling. If the furnace is not in use, close the furnace door properly to prevent moisture from corroding the furnace chamber.
(II) Precautions
1. The electric furnace and controller must be operated in a place where the relative humidity does not exceed 85% and where there are no conductive dusts, explosive gases, or corrosive gases that can damage metal insulation and electronic components.
2. Periodically check whether all connecting parts of the conductive system of the electric furnace and controller are in good condition.
3. The furnace temperature must not exceed the maximum temperature.
Operating procedures for the nitrogen determination apparatus
(I) The whole setup consists of two main parts: the electric heating digester and the distiller. To increase the detection speed of protein content determination, the key is first to accelerate the digestion and decomposition time of the sample.
(II) If gas overflows during digestion, increase the water flow rate of the suction pump.
(III) Because NaOH solution is prone to forming solidified buildup in the tube when not used for a long time, after work is finished each day, move the external NaOH rubber tube into a distilled water bottle and rinse by suction several times; before the next use, 100 ml of NaOH must be discharged during distillation to prevent dilution of the NaOH.
(IV) Each time sample distillation is completed, the digestion tube must be removed quickly to prevent the liquid in the digestion tube from being sucked back into the evaporation furnace and corroding the electrode plate.
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Support!
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Is there a laboratory centrifuge? What rotation speed is generally used? What specifications must the centrifuge used for rapid detection of melamine reach?
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Thanks to the OP for sharing!!
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Thanks! Bookmarked
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Thanks~~ Bookmarked
1.
Turn on the power and preheat for 20 minutes.
2.
Adjust to the required wavelength. (Turn the wavelength adjustment knob.)
3.
Zero adjustment (0%T)
Place the light-blocking body into the sample holder and pull the sample holder rod so that it enters the light path. Then press the "0%T" button on the instrument to complete the zero adjustment.
4. 100% adjustment
Place the blank sample into the sample holder (put the background into the first hole of the colorimetric holder, and the sample cover must be closed), and pull the sample holder rod so that it enters the light path. Then press 100%T on the instrument; when "BL" appears on the screen, the 100% adjustment is complete. (When adjusted to 100%, it displays 0.000 in absorbance mode and 100.0 in transmittance mode.)
5. Measurement
Press the "Function" key to switch to measurement mode, close the sample compartment cover, and the meter displays 0.000. Then pull the sample holder so that the test sample enters the test path position; the currently displayed data is the value of the sample being tested.
Prepared by:
December 30, 2008
Operating Procedures for the TG328A Optical Analytical Balance 1.
Calibrate the balance to a level position, and set all mechanical weights to zero.
2.
Connect the power supply and preheat for 30 minutes.
3.
Gently open the side door and weigh the sample. The sample must not be placed directly on the balance pan. Accurate to one ten-thousandth of a gram, weighing range 0~199.990 g.
4.
When weighing an object, the weights must be selected in order "from large to small," that is, starting with a weight approximately equal to the mass of the object being weighed, gradually increasing the weights from large to small, adding or removing weights according to the direction of the pointer deviation, until the reference line appears on the projection screen and the reading stops within 10 milligrams.
5.
After weighing is completed, remove the object being weighed, and set all mechanical weight dials to zero. Close the balance doors properly, cut off the power supply, and put on the dust cover.
Prepared by:
Year Month Day
Operating Procedures for the SK-95-10 Box-Type Resistance Furnace 1.
Connect the resistance furnace and the controller, and connect the power supply.
2.
A new resistance furnace should be preheated for about 20 hours as specified.
3.
When in use, adjust the controller temperature according to the sample requirements.
4.
Place the sample into the furnace chamber, close the furnace door properly, and begin heating.
5.
After the specified temperature is reached, start timing; when the required time is up, turn off the power.
6.
Open the furnace door a crack and wait 30 minutes before opening the door to take out the sample.
Prepared by:
Year Month Day
Operating Procedures for the 101-0 Electric Thermostatic Drying Oven 1.
Set the blower switch to the off state, set the temperature to the low-temperature state, and connect the power supply.
2.
Press the set button to set the required temperature, then press the set button again to return to measurement state.
3.
Insert a thermometer above the ventilation hole, and use the temperature at this point as the actual temperature.
4.
Place the sample in for drying and adjust according to the required time; do not open the door during this period.
5.
After drying, take out the sample and turn off the power.
Prepared by:
Year Month Day
--------------------------------------
Concise language, thank you for your guidance!
--------------------------------------
The optical analytical balance is too troublesome; I don't know how to use it.
--------------------------------------
Operating Procedures for the Sample Grinder
(1) Place the grinder on a flat tabletop.
(2) Before use, check whether the power supply and the grinder are normal, and whether there is residual sample from the previous use inside the grinder.
(3) Check whether the grinder screen is of the required specification.
(4) The grinder should be started before placing the sample from the hopper into the grinder.
(5) After the sample is ground, wait until the grinder stops rotating before cleaning out the sample.
(6) It is strictly forbidden to start the grinder without closing the grinder door.
Operating Procedures for the Electronic Analytical Balance
(1) Checks before use:
1. Check whether the balance is level and whether the balance pan is clean. If there is dust, brush it clean with a soft-bristle brush.
2. Check whether the silica gel desiccant in the balance chamber has changed color. If it has changed color, replace the desiccant.
(2) Calibration of the balance:
The balance must be powered on for 60 minutes to obtain a stable working temperature. After it stabilizes, when pressing the "T" key displays "0.0000 g," press and hold the "C" key; when "CAL" is displayed, place the calibration weight in the center of the weighing pan, and at the same time close the glass door of the draft shield. Wait for the balance to calibrate automatically internally. When the display shows the nominal value of the calibration weight and the buzzer sounds once, calibration of the balance is complete.
(3) Operating steps
1. Power on: Leave the balance unloaded and press the "on" key once. The balance displays a self-test (all segments flash, etc.). When the balance stabilizes and is calibrated, weighing can begin.
2. Power off: Press and hold the "off" key until "OFF" appears on the display. Release the key.
3. Simple weighing: When the balance displays "0.0000," place the sample on the weighing pan and close the glass door of the balance draft shield. Wait for the balance to stabilize and display the unit "g," then read the weighing result.
(4) Precautions:
1. The analytical balance should be placed on a firm bench in a room with uniform temperature, avoiding vibration, moisture, direct sunlight, and protection from corrosive gases.
2. Check whether the balance is intact before and after weighing, and keep the balance clean. During weighing, close the balance doors as you go.
3. The load on the balance should not exceed the maximum capacity, and items should be placed in the center of the pan.
4. Chemical reagents and samples must be weighed in appropriate containers, such as weighing bottles, watch glasses, or glassine paper, etc., and must not be placed directly on the balance pan for weighing.
5. The balance should be calibrated before first use, for regular weighing service, and when its placement position is changed. Calibration weights should be stored properly.
Operating Procedures for the Spectrophotometer
(1) Installation and adjustment of the instrument
1. The spectrophotometer is a precision instrument made using the photoelectric principle, used for qualitative or quantitative analysis by measuring the optical density or absorbance of a solution. The specified principles must be followed during use.
2. The instrument must be installed in a clean and dry room, with a working temperature of 5-35°C.
3. Avoid vibration; it should be placed on a stable workbench during use.
4. Avoid direct sunlight.
5. Keep away from high-intensity magnetic fields, electric fields, and electrical equipment that generates high-frequency waves, and keep away from places with corrosive gases such as hydrogen sulfide, sulfurous acid, and fluorine.
6. Power supply: (220±22) V; (50±1) Hz, and a grounding wire must be installed.
(2) Use and maintenance of the instrument
1. Turn on the power and preheat for 30 minutes.
2. Place the blank into the first cell as the reference, and use the others as sample cells.
3. Adjust '0' and full scale, then pull the sample cell holder rod in sequence. After the pointer stabilizes, read the absorbance A value directly. Each time an 'A' value is read, '0' and full scale must be adjusted once, and the reading should be taken quickly to prevent inaccurate readings caused by excessive time.
4. Do not touch the light-transmitting sides of the cuvette with your hands; keep them clean, transparent, and free of dirt and water droplets.
5. The liquid in the cuvette should be free of bubbles, and must not splash outside into the dark chamber of the spectrophotometer, to prevent corrosion damage and to prevent the solution, after evaporation and vaporization, from filling the light path of the sample chamber and causing measurement errors.
6. After measurement is completed, fully clean the cuvette and let it dry for later use. Place silica gel desiccant in the dark chamber of the spectrophotometer to prevent the lamp chamber from becoming damp and the reflector from becoming moldy or contaminated.
7. The moisture-proof silica gel in the drying cylinder should remain blue. If it turns red, take it out and replace it to prevent the instrument from becoming damp.
8. After each use, cover the instrument promptly and place several bags of silica gel desiccant inside.
9. Keep the area around the instrument clean and tidy, with no clutter.
Fat Extraction Apparatus
(1) The Soxhlet extractor is formed by connecting three parts: the extraction tube, the extraction flask, and the condenser. The extraction tube has a siphon tube and a vent tube on both sides. The filter paper packet containing the sample is placed in the extraction tube, and the solvent is added to the extraction flask. When heated, the solvent vapor passes through the vent tube to the condenser, and the condensed solvent drips into the extraction tube to extract the sample.
(2) When the solvent level in the extraction tube exceeds the height of the siphon tube, the solvent containing fat in the extraction tube flows through the siphon tube into the extraction flask. After repeated extraction in this way, the fat in the sample gradually becomes fully concentrated in the extraction flask. After extraction is completed, the fat content of the sample is calculated from the decrease in weight of the sample filter paper packet before and after defatting. Since the organic solvent extracts not only fat from the sample but also other fat-soluble components, the result measured in this experiment should be the crude fat content.
(3) Precautions
When drying the filter paper packet in the oven to remove solvent, to prevent ether vapor from burning and catching fire, the oven door should first be opened halfway.
Operating Procedures for the Vacuum Pump
Use and precautions
1. First unscrew the oil filler plug, add oil through the oil filler hole up to 2/3 of the oil mark, then add a small amount of pump oil through the intake port to lubricate the pump chamber, to avoid seizing and overheating after startup. Use No. 1 vacuum pump oil, or imported light high-grade engine oil for cars may also be used as a substitute.
2. Connect the power cord as specified (for a three-phase motor, note that the motor rotation direction should be consistent with the arrow direction on the pump bracket). Remove the rubber plug cap on the exhaust pipe, run it idly for a moment, and then begin normal operation.
3. The pipeline connected to the pump intake port should not be too long. Be sure to check the external connecting pipeline, joints, and container of the vacuum pump; they must absolutely not leak and must be sealed. Otherwise, the ultimate vacuum and the service life of the vacuum pump will be affected.
4. Working environment of the pump: operate within a temperature range of 5°C-40°C, with relative humidity not greater than 85%, and intake pressure less than 1.3*1000. For vacuum pumps with a pumping speed above 0.5 L/s, a gas ballast valve is installed. If the relative humidity is relatively high, the gas ballast valve can be opened for purification, so as to purify the pump oil and extend the service time of the pump oil; close it promptly after purification is completed.
5. The suction port of this pump must not be continuously open to the atmosphere for more than 3 minutes.
6. This pump is a high-precision product, and it is not a corrosion-resistant vacuum pump. It is recommended to use it with a filter. It cannot work under any of the following conditions:
(1) It must not suction gases containing particles or dust, or colloidal, watery, liquid, or corrosive substances.
(2) It must not suction explosive gases or gases with excessively high oxygen content.
(3) It must not operate under long-term pumping with system leakage or with a container matched to the vacuum pump that is too large.
(4) It must not be used as a gas transfer pump, compression pump, etc.
Operating Procedures for the Constant-Temperature Water Bath
(1) Instructions for use
1. Before energizing, first add an appropriate amount of water to the water tank; distilled water is best. Never run without water or with the water level below the electric heating tube, to prevent the electric heating tube from bursting and being damaged.
2. The temperature control system of this instrument uses a TDA-8002 pointer-type temperature controller. During use, connect the power supply; the green light comes on, the instrument begins to work, and the heater begins heating. Then, according to the temperature you need, turn the temperature setting knob. When the green light is on, it indicates heating; when the red light is on, heating stops and the heater stops heating. When the red and green lights alternate flashing, it indicates entry into the constant-temperature state. If you want to change the temperature, turn the temperature setting knob at any time. During use, the temperature indication displayed by the temperature controller is the actual required temperature.
(2) Precautions
1. When the water bath is in use, it must be reliably grounded, and water must not overflow into the control box, so as to avoid danger.
2. It must be used with the specified power supply - 220V. Never connect it to a 380V power supply, otherwise the equipment will be damaged.
Equipment damaged.
Operating Procedures for the Constant-Temperature Drying Oven
(1) Operating method
1. Connect the power supply.
2. Adjust the temperature controller to the required temperature.
3. When the temperature indication reaches the set value, place in the item to be tested.
4. Once measurement begins, opening the oven door should be avoided.
(2) Calibration method
1. Calibrate by comparing a 150°C thermometer with the temperature controller.
2. When the oven temperature reaches the set temperature, place the 150°C thermometer inside.
3. Time for 60 minutes; when the temperature reaches a stable state, read the temperature value.
4. Repeat steps 2 and 3 to calibrate at least three times.
(3) Maintenance and care
1. Keep the inside and outside of the oven clean at all times.
2. Ventilate regularly to remove moisture.
(IV) Precautions
1. Avoid putting in strong acids, alkalis or corrosive substances.
2. If the oil liquefies, it should be placed on a tray, so that oil adhering to the outside of the bottle does not drip into the chamber.
Operating procedures for the high-temperature furnace
(I) Instructions for use
1. The high-temperature electric furnace is a high-temperature heating device with a temperature controller; it is lined inside and out with refractory material, in the middle are silicon carbide rods or nickel-chromium resistance wires serving as the heat source, and inside the high-temperature chamber there is a thermocouple connected to the temperature controller to control the furnace temperature.
2. The high-temperature furnace should be placed on a sturdy, stable bench; do not place flammable or explosive items around the furnace; when in use, the furnace chamber should be lined with clean refractory bricks to prevent the heated object from sticking to the furnace chamber.
3. When the electric furnace is used for the first time, or used again after being out of service for a long time, it must be dried out. Drying time: 4 hours at room temperature 20°C, 4 hours at 200-600°C. When in use, the furnace temperature must not exceed the maximum temperature, so as not to burn out the electric heating elements. It is also forbidden to pour various liquids or molten metal into the furnace.
4. After ignition is complete, first cut off the power supply, then open the furnace door halfway and let it cool slightly before fully opening the furnace door; this prevents the furnace chamber from cracking due to sudden cooling. If the furnace is not in use, close the furnace door properly to prevent moisture from corroding the furnace chamber.
(II) Precautions
1. The electric furnace and controller must be operated in a place where the relative humidity does not exceed 85% and where there are no conductive dusts, explosive gases, or corrosive gases that can damage metal insulation and electronic components.
2. Periodically check whether all connecting parts of the conductive system of the electric furnace and controller are in good condition.
3. The furnace temperature must not exceed the maximum temperature.
Operating procedures for the nitrogen determination apparatus
(I) The whole setup consists of two main parts: the electric heating digester and the distiller. To increase the detection speed of protein content determination, the key is first to accelerate the digestion and decomposition time of the sample.
(II) If gas overflows during digestion, increase the water flow rate of the suction pump.
(III) Because NaOH solution is prone to forming solidified buildup in the tube when not used for a long time, after work is finished each day, move the external NaOH rubber tube into a distilled water bottle and rinse by suction several times; before the next use, 100 ml of NaOH must be discharged during distillation to prevent dilution of the NaOH.
(IV) Each time sample distillation is completed, the digestion tube must be removed quickly to prevent the liquid in the digestion tube from being sucked back into the evaporation furnace and corroding the electrode plate.
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Is there a laboratory centrifuge? What rotation speed is generally used? What specifications must the centrifuge used for rapid detection of melamine reach?
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