To create a Closed Loop Temperature Control circuit you need at least 4 things, usually 5:
1) Heater
2) Power Switch
3) Controller
4) Sensor 5) Limit Controller with additional sensor (optional but highly recommended)
Heater: This already exists in your oven or furnace. Determine the power (voltage, wattage, amperage) and number of phases. If it is three phase, determine if you need to switch two legs or three, which can be noted by the number of fuses on the main power leading to the heater(s) in your current configuration (see related post).
Power Switch: From this power and heater info you can select the power
Catalysis is the process of modifying a chemical reaction with the use of a catalyst. This process only works with chemicals that have an existing reaction, and it is used to accelerate the reaction for commercial purposes. Catalysis occurs faster than a standard chemical reaction because catalysts require less activation energy, which is the minimum level of energy necessary to initiate a chemical reaction.
Catalysis Working Principle
When a chemical is placed with a compatible catalyst, there is a reduction in the free energy required for the chemical to reach the transition state for that particular reaction. Catalysts can influence the reaction environment, depending on the specific reaction requirements.
For example, catalysts can produce more heat, form specific
The Suib Group at the University of Connecticut collaborated with Hiden Analytical to determine the effectiveness of Hiden’s Compact SIMS (Secondary Ion Mass Spectroscopy) Analysis System for various research applications, including:
Surface Contamination on Silver Electrodes
Catalyst Dopant Homogeneity
Carbon Contamination and Removal via heat treatment
You can extend service life of ISO-KF seals in high temperature applications by switching from generic fluoroelastomers (FKM) such as Viton, to perfluoroelastomers (FFKM), and by ensuring the seal is properly sized.
ISO-KF (or ISO-QF or ISO-NW) type flange seals provide an economical, convenient and simplified means of constructing vacuum systems. However, despite the efficiency offered by these flanges, you may face premature seal failure and unscheduled equipment downtime when standard AS-568A o-rings are specified for locations which will be exposed to >/= 150°C and/or harsh process effluent, particularly in heated forelines and exhaust lines.
Serious errors in calibration and display can result if the wrong sensor type is selected on the controller versus what is actually wired to it. Only a physical check of sensor wire and sensor prompts can detect this condition. A systems validation test checking at several temperature points with an external calibrator or measurement device is highly recommended. See chart below.
This is especially important if using a hi-limit sensor, as the limit sensor may be set incorrectly and will not shut down the system safely in the case of an overtemp condition.
Below are examples of improper readings shown when the controller is set up for default Type J sensor:
There are many factors to consider when choosing a power control device. The role of the output device is to receive a signal from the temperature controller and switch electric current ON and OFF to the heater. When possible, it is convenient to have the output device incorporated into the temperature controller.
Let’s take a moment to explore the different types of switching devices and their advantages and disadvantages:
Electromechanical Relays – an Electromechanical Relay is a mechanical device with moving parts. When power is called for, the control output supplies current to the relay’s wire coil, creating a magnetic field, thus pulling the upper metal contact of the relay down closing the circuit and allowing the load current to flow through the contacts to the heater. Conversely, when the control output cuts off the current signal, the magnetic field is lost and the relay contact opens cutting off current to the heater. The above scenario is for a
Residual Gas Analyzers (RGAs) are quadrupole mass spectrometers that provide for routine, fast, wide dynamic range measurements of the partial pressures of the species resident in your vacuum chamber or system. Vacuum levels can be analyzed from as low as 10-14 Torr to as high as 10-3 Torr depending on the type of analyzer design. Analysis at higher chamber pressures can be accomplished by connecting your RGA to a differential pumping system.
The term "vacuum," as it pertains to the use of vacuum to study its effects or to enable something to happen in a high technology sense, has a broad range of definitions and sub-categories.
If you are depositing dielctric layers using RF and DC (or AC) power simultaneously, you run the great risk of damaging your DC supply and/or creating interference problems. A well designed and constructed "Blocking Filter" will prevent these issues from occurring.
Here is an example:
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The filter enables the low-frequency DC to pass to your sputter source while blocking the high-frequency RF from migrating back into the DC portion of your power delivery set-up.
IES Technical Sales is a high technology manufacturers representative and distribution firm serving the northeast U.S., specializing in vacuum & thin film, flow & pressure, thermal and related metrology applications.
