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Documents: Air power supply and controller for air heaters
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Table of contents |
1. |
Power Supply |
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2. |
Temperature Controller |
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3. |
Temperature Sensor |
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4. |
Control Panel (Customized) |
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5. |
Hot Air Controller (finished product) |
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* For the air source, see the right page ? |
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* For the air source, see the right page ? |
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1. Power Supply
The following types of power supply and controllers can be used for hot air heaters (air heaters).
Slidac is recommended if only voltage adjustment is required. Unit is heavy and sturdy.
SCR type voltage regulator is recommended if your requirement is a compact, light weight, and low cost unit with various controls.
Comparison List of Various Power Supply Methods
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Classification, product name |
Overview |
Advantages/disadvantages |
Remarks |
Bolt slider (Slidac) |
Iron core type friction transformer whose output voltage can be varied in the range of 0 to 120%. |
Unit is sturdy. Voltage can be higher than the power supply voltage. Easy to measure voltage as voltage waveform does not change. Cost increases significantly for large-capacity units. Automatic control is difficult. |
Reference example S-260-5 (200v-5A) manufactured by Yamabishi, approximately 17,000 yen. S-260-10 (200v-10A) approximately 31,000 yen. S-260-20 (200v-20A) approximately 80,000 yen. |
SCR slider (Bar Tap) |
SCR (semiconductor) type phase control voltage regulator. Controls electric power with high speed switching (60 Hz 120 times per second). |
Compact, lightweight, and low cost.
The unit will be damaged if overloaded.
Take care while measuring voltage, as the voltage waveform changes significantly. Sound may be generated depending on the status. Take care as plenty of electromagnetic noise is generated.
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Reference example: Tokyo Rikosha product
? For embedding in equipment with VR.
VP-10C (200v-10A) 10,700 yen
? For embedding in equipment with external VR.
VPJ-20C(200v-20A), 13,500 yen
? Finished product with case
VPM-10C(200v-10A) 15,300 yen
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SCR controller |
SCR (semiconductor) type phase control voltage regulator with various control functions. Used in combination with temperature controller |
Features are the same as the basic structure is the same as the above SCR slider.
There are models with various control functions, select as required for the application.
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Reference example: Tokyo Rikosha product
?Used in combination with temperature controller
VSCD-20(200v-20A) 14,800 yen
?With temperature controller, finished product with case
HT-152 (200v-15A) 89,000 yen.
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SSR (semiconductor relay) |
This unit does not functional independently, the heater electric power can be varied if it is turned ON-OFF more than twice per second. |
Compact, lightweight, and low cost compared to SCR type, and can be controlled automatically. Less noisy compared to SCR method. However, SCR method is better for the heater.
It has the same disadvantages as the SCR type, it cannot be used independently and can be used only with the temperature controller. The switching speed is low, and there is slight variation in hot air temperature which impacts service life in some cases.
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Reference example: Omron product
G3PB-225B-VD(200v-25A) 4500 yen
Cycle control cycle must be 0.5 seconds or less
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Information on Slidac
The name Slidac is a trademark of Toshiba Corporation, but it is currently not manufactured by Toshiba.
However, this name is almost like a common name and we have used the name in this description.
Incidentally, bolt slider and bar tap are trademarks of YAMABISHI, and Tokyo Rikosha.
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Details of Various Methods
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Bolt slider (Slidac)
It is suitable for use in simple configurations as shown in the figure below. It is sturdy and can be used conducting experiments by setting the conditions.
Bolt slider example
Yamabishi manufactured product S-260-10
Input AC 200 V
Output 0 to 260 V, 10 A
Price approximately 31,000 yen.
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SCR slider (Bar Tap)
It is a bolt slider (Slidac) with a semiconductor. Compact, lightweight, and low cost. However, it does not have high control functionality, voltage can be adjusted by rotating the knob. It is operated manually, monitoring the temperature with a thermocouple thermometer is preferred.
There has been a decrease in the prices of SCR controllers (such as VSCD series of Tokyo Rikosha) with advanced functions, and there is almost no difference (see the price list of VSCD series from Tokyo Rikosha). It is preferable to use VSCD series based this difference in prices. VSCD series also allows manual adjustment of voltage by attaching an external knob.
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SCR slider example (for embedding)
Tokyo Rikosha Baritap VP-10C
Input AC 200 C output 0 to 196 V 10 A
10,700 yen
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Tokyo Rikosha assembled unit in case
Baritap Controller VPM-10C
Input AC 200 v output 0 to 196 v 10 A
15,300 yen.
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SCR Phase Controller
It has the same SCR phase control method as SCR slider mentioned above, it is provided with various control functions to enable advanced usage.
If the hot air heater, SCR controller, and temperature controller are connected as shown in the following figure, the unit controls such that the hot air temperature is maintained at the set value. Various protection circuits can also be incorporated easily.
However, to use hot air heaters with stability, not only advanced electric control, stability of air flow rate is also required to be maintained. One of the foremost problems of hot air heaters is overheating burnout due to unexpected stoppage of air. When the air supply completely stops, the built-in temperature sensor of hot air does not sense anything, and high voltage continues to be applied to the heater and it will be burn-out.
Triac or SCR (2 inverse parallel connections) is used as the phase control element for AC, but based on our experience, Triac tends to be susceptible to noise, and controller using SCR is recommended.
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SCR Phase Controller VSCD series of Tokyo Rikosha
Input signal |
4 to 20m ADC (200 O) |
Rated voltage |
100/110, 200/220 V shared |
Rated current |
20, 30, 50, 75, 100 A |
Soft up |
Approximately 0.2 to 8 seconds variable |
Model |
VSCD-20 |
VSCD-30 |
VSCD-50 |
VSCD-75 |
Rated current |
20 A |
30 A |
50 A |
75 A |
Width |
59 |
59 |
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Depth |
135 |
135 |
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Height |
178 |
178 |
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Weight |
11.02 lbs (1.1kg) |
11.02 lbs (1.1kg) |
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Cost |
14,800 yen |
17,000 yen |
37,800 yen |
53,100 yen |
* These prices are from the price list of Tokyo Rikosha
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Finished product type with case Heater controller
This heater controller is provided with a temperature controller for easy control of temperature and controller for electric power to heater enabling accurate temperature control by externally connected temperature sensor and panel settings.
The contents (excluding the heater) of the diagram on the left has been captured in one box. It costs 3 thrice that of an equivalent configuration obtained by combining individual units.
Item |
HT-152 |
HT-302 |
Input |
Rated voltage |
200/220 (V) |
200/220 (V) |
Output |
Rated current |
15 (A) |
30 (A) |
Input |
Temperature sensor |
Standard: K type (J, R, S, others) |
Outer dimensions |
Width (mm) |
105 |
105 |
Depth (mm) |
160 |
175 |
Height (mm) |
166 |
166 |
Cost |
89,000 yen |
113,000 yen |
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SSR (semiconductor relay)
Utilizing the high speed and long service life characteristics of SSR, the electric power can be controlled by changing the ratio of ON time and OFF time by repeating ON-OFF 2 or more times per second Generation of noise can be almost eliminated by turning ON-OFF when the voltage of AC waveform is zero. Electric power of heater can be controlled by combining with a temperature controller (for example Omron E5CN-QT) having such a control function.
This method is simpler than the SCR phase control method mentioned above. As a slow speed switching of 2 times per second is used, there is a slight variation in the temperature of the hot air temperature of the heater. It may also affect the service life of the hot air heater, though SCR phase control method is better for the heaters, SSR method can be used for many applications.
However, cost of the electric power controller of the SCR phase control method has reduced, and usage of SSR is no longer necessary. However, to use SCR phase control, it is necessary to use a current output type (E5CN-CT) for the temperature controller, this increases the cost by 5,000 yen, and the total difference works out to be 15,000 yen.
In addition to the advantage of less noise generation mentioned above for the SSR method, there is no distortion of electric waveform as in the phase control method, and is advantageous from the perspective of power supply (less reactive current and less power transmission loss).
SSR Omron manufactured G3PB series
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3. Temperature Sensor
Monitoring of hot air temperature is essential if repeatability is required while using the hot air heaters, and sensor of hot air temperature is also essential to control and keep hot air temperature constant at a certain value.
Temperature sensor for hot air can be incorporated in our hot air heater (option +S specification). Usually the K thermocouple is used as the sensor and is located near the hot air outlet. (R type thermocouple with long service life even at high temperature is also available)
The above mentioned sensor can detect hot air outlet temperature of the hot air heater, but in some cases it may be necessary to detect the temperature of the object that is heated or its vicinity. For such cases, an external thermocouple is placed close to the object that is heated. ? See thermocouple
Thermocouples are normally K thermocouples made from wires that are of small diameters (for example, wire diameter ?0.0078 in (0.2 mm). Thicker wires are required to be used for the thermocouples considering service life if heating at higher temperatures is required, in this case, speed of response decreases. Our company uses R thermocouple with wire diameter ?0.0118 in (0.2 mm) taking into account high temperature and speed of response.
If the temperature of the object that is heated is required to be measured and the thermocouple cannot be installed in or near the object, a radiation thermometer will have to be used.
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K thermocouple type temperature sensor installed in a hot air heater ?0.157 in (4 mm)
Detects the temperature of hot air that flows out.
Related information ?Thermocouple
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Application |
Type of temperature sensor |
Usage Method |
Remarks |
Detects the temperature of the hot air or object that is heated, and is required when a temperature controller is used |
Built-in temperature sensor of air heater (thermocouple) |
Temperature of the hot air outlet is controled in combination with a temperature controller or hot air temperature is monitored by providing a temperature indicator |
Built-in the heater (optional) Standard is K type R is also available as an option |
External thermocouple |
Install and use a thin (?0.0078 in (0.2 mm)) K thermocouple in or near the object. R thermocouple is used for high temperatures |
Thermocouple of the required size can be provided (diameter and length)
K type approximately 1,000 yen/m R type approximately 15,000 yen/m
As R type is expensive, minimum length is used and inexpensive lead wires are used from the R type to the instrument. |
Radiation thermometer |
This is used when the thermocouple cannot be installed in or near the object to be heated. Temperature of object that is heated can be measured without contact |
Reference example: Keyence product
Amp separated type radiation thermometer FT series
Sensor head FT-H 44,900 yen.
Amplifier unit FT-50 29,900 yen. |
Example of Radiation Thermometer
Information on the FT series manufactured by Keyence is posted below as an example of radiation thermometer used as a temperature sensor suitable for embedding in equipment.“Surface temperature” can be Visualized Without Contact
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Radiation thermometer manufactured by Keyence
FT series sensor head
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Amplifier
Input/output circuit diagram
FT-50, FT-55 (NPN)
Explanation image of “Amplifier separation type FT series”
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Classification |
Small spot |
Medium distance |
Long distance |
Model |
FT-H10 |
FT-H20 |
FT-H30 |
Detection temperature range |
32 to 932ºF (0 to 500ºC) |
Minimum visual field diameter |
?0.059 in (1.5 mm) |
?0.236 in (6 mm) |
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Measured distance |
1.37 in (35 mm) |
4.72 in (120 mm) |
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Aim |
2 point spot light using visible-light laser |
Detection element |
Thermopile |
Detection wavelength |
8 to 14µm |
Emissivity (e) correction |
0.1 to 1.99 (steps of 0.01) |
Weight |
Approximately 120 g |
Price (yen) |
44,900 yen |
44,900 yen |
39,900 yen |
* Visible light semiconductor laser wavelength 655 mm (FDA class 1/IEC class 1/JIS class 1 |
Model |
NPN output |
FT-50 (DIN rail) - FT-55 (panel installation) |
PNP output |
FT-50P (DIN rail) - FT-55P (panel installation) |
Power supply voltage |
DC 12 to 24 V ripple (PP) 10% or less |
Display resolution |
32.18 to 33.8ºF (0.1 to 1ºC) |
Hysteresis |
Variable |
Responsiveness |
HSP, 30, 100, 200, 500, 1000, 5000 ms selection (HSP: Typical example 10 ms, maximum 15 ms) |
Control output |
NPN (PNP) open collector x 2 ch, DC 40 V (30 V) or less |
Analog output |
4 to 20 mA maximum load resistance 260 O analog output The upper and lower limit values?of the range can be set arbitrarily |
Price (yen) |
29,900 yen |
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Example of Controller Using Radiation Thermometer |
Since the output of the Keyence FT series analog output was only in the range 4 to 20 mA, it was considered that using 4 to 20 mA for configuration of the temperature adjustment circuit was the easiest to match with the characteristics of the K thermocouple. (4 mA ? 20 mA supports 32ºF (0ºC) ? 932ºF (500ºC))
In this way, if the output of the FT series radiation thermometer is matched to the characteristics of the thermocouple, the above mentioned control circuit as described above can handle the later stages.
The previous control method adjusts the hot air temperature to the set value, while the current control method adjusts such that the object to be heated is at the set temperature, and there are many applications for which this method is more convenient.
Since this system works to maintain the temperature of the object to be heated at the set value, while the temperature of the object to be heated is significantly lower than the target value, a 100% voltage (power supply voltage) continues to be applied to the hot air heater, and the heater may get burnt depending on the air volume.
In such a case, either the maximum voltage has to be limited (limit maximum voltage with output adjustment knob), or use with a setting such that there is no problem even if the supply voltage continues to be applied. (air is continuously made to flow with minimum air flow rate)
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4. Customized Control Panel
To use only the hot air heaters independently, you can select and use the appropriate power supply and control from the various options given in the table above, to incorporate our heater into automatic machines, operation link with the automatic machine, safety devices and other measures are required, and a dedicated control panel that works accurately with that machine is absolutely necessary.
For such cases, Fintech selects the power supply and control with the configuration most suitable for our heater, we manufacture the control panel embedded with the control circuit on a made-to-order basis.
The following is a broad time schedule from the beginning of business negotiation to design, manufacture, and delivery.
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0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 days |
(1) Confirmation and examination of specifications |
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(2) Rough estimation |
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(3) Provisional order |
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(4) Detailed design ? Approval |
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(5) Final quote |
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(6) Formal order |
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(7) Production |
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(8) Inspection, and delivery |
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The configuration of the standard control panel is as follows. The configuration of the control panel is decided based on this by adding necessary additional functions and deleting unnecessary functions. The cost of control panel is determined by these requirements, capacity of hot air heater, and air flow rate. The quote will change depending on the distance if installation and inspection is required at the location of the customer.
Control panel (electric control unit)
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Item |
Contents |
Remarks |
Control Overview |
It has two driving states (1) and (2), and timing for each can be set with a timer. Each has a temperature adjuster, and the air volume can also be individually adjusted. Even when the operation is turned OFF, air is allowed to flow for a fixed time to cool the unit. Air and heating element temperature are monitored and power supply to the unit is stopped under any abnormal circumstances. External control is possible. |
The air control unit is not included in the control panel. An air control unit consisting of an electromagnetic valve, flow meter, flow control valve, and a flow switch is provided separately. |
Control unit |
Basically it is a relay sequence. However, if the number of control relays increase, a sequencer (Mitsubishi) is used. |
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Safety device |
Earth leakage breaker, fuse, air flow SW, heating element temperature monitoring, emergency stop SW, and others |
2 sensor type (/+2S) is used for the hot air heater. |
Driving operation switch, and knob |
Main Power Supply SW, Operation (1) SW, Temperature Controller (1), Timer (1), Operation (2) SW, Temperature Controller (2), Timer (2), Stop, Timer OFF, and External Control SW |
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Running status display |
Power Supply, Operation (1), Operation (2), Voltmeter, Ammeter (analog meter), Temperature Controller (1), and Temperature Controller (2) |
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Error display |
Air volume, heating element overheating, and others |
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Control of air source |
If a dedicated pump is provided instead of common air piping, the control circuit of the pump is also included. |
Electromagnetic pumps, rotary blowers, compressors, etc. |
Item |
Contents |
Remarks |
Overview of Configuration |
2 solenoid valve flowmeter circuits are connected in parallel after the flow switch. |
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Flow switch |
A structure that detects the flow of air with a reed switch. |
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Flowmeter |
Acrylic float type is normally used. Digital type can also be used. |
Digital type is slightly more expensive. For the float type, reading accuracy is low, and measurement principle is direct |
Flow control valve |
This valve is not provided, and the one attached to the flowmeter is used |
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Pressure gage |
Measures pressure at the air inlet. Pressure can also be measured at air outlet. |
The pressure range for measurement is determined by the type of air source used. |
Mount |
The pressure gage, flow meter, and flow control valve are mounted on a panel in the control box. Rest are built-in the control box. |
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Piping |
Connected with a urethane tube unless otherwise specified. |
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Air pump |
Normally, pumps are not built-in the box except in the case of very small pumps. Installed separately. |
Electromagnetic pumps, rotary blowers, compressors, etc. |
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Hot air heaters SAH series Dedicated controller Fintech funtech-jp.com
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Explanation of control function |
Example of model number |
Price index |
Specifications |
1 |
FCL type Simple structure Easy to handle as the controller is provided with the minimum required simple functions. Flow rate control using float type flow meter with flow control valve. Voltage control using SCR phase control |
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FCL/L05-050 |
10.07 |
Power supply voltage 100 V
Maximum current 5 A
Flowmeter 13.2 gal/min (50 L/min). |
FCL/H10-100 |
12.80 |
Power supply voltage 200 V
Maximum current 10 A
Flowmeter 26.4 gal/min (100 L/min). |
2 |
FCN type Standard Temperature Control Function
The most common controller with the function for automatically controlling the set temperature using a temperature controller.
Flow rate control using float type flow meter with flow control valve.
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FCN/F05-050 |
10.44 |
Power supply (100 to 240 V)
Maximum current 5 A
Flowmeter 13.2 gal/min (50 L/min).
Options none |
FCN/F20-100/3 |
13.21 |
Power supply (100 to 240 V)
Maximum current 20 A
Flowmeter 26.4 gal/min (100 L/min)
Options disconnection detection, communication |
3 |
FCH type Temperature Control Function and Air ON/OFF In addition to the function of automatic control to the set temperature using the temperature controller, it has a multifunction controller for turning air flow ON/OFF using a solenoid valve. Flow rate control using float type flow meter with flow control valve. |
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FCH/F05-050 |
16.74 |
Power supply (100 to 240 V)
Maximum current 5 A
Flowmeter 13.2 gal/min (50 L/min).
Options none
FCH/F20-100/3 19.51 Power supply (100 to 240 V) Maximum current 20 A
Flowmeter 26.4 gal/min (100 L/min)
Options disconnection detection, communication |
FCH/F20-100/3 |
19.51 |
Power supply (100 to 240 V) Maximum current 20 A
Flowmeter 26.4 gal/min (100 L/min)
Options disconnection detection, communication |
4 |
FCM type Temperature Control and Air Flow Rate Control In addition to the function of automatic control to the set temperature using the temperature controller, advanced control of air is possible.
Advanced air flow rate control with high accuracy is possible using mass flow controller |
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FCM/F05-050 |
43.13 |
Power supply (100 to 240 V) Maximum current 5 A
Maximum flow rate setting 13.2 gal/min (50 L/min).
Options none |
FCM/F20-100/3 |
46.11 |
Power supply (100 to 240 V) Maximum current 20 A
Maximum flow rate setting 26.4 gal/min (100 L/min)
Options disconnection detection, communication |
* Even if the controller is of free voltage, the hot air heater that is connected should be a model with the rated voltage corresponding to the power supply voltage |
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