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The main difference in chemical composition between 316 and 304 stainless steel is that 316 stainless steel contains molybdenum. This gives 316 stainless steel better corrosion resistance, particularly in high-temperature environments.
The density of 316 stainless steel is also higher than that of 304 stainless steel. In terms of applications, 304 stainless steel is widely used in industrial equipment, household decoration, food processing and medical industries. By comparison, 316 stainless steel is more commonly used in equipment exposed to seawater, food-grade industrial applications and highly corrosive environments.
The difference between 304 and 201 stainless steel also lies in their chemical composition. The chromium content of 304 stainless steel is higher than that of 201 stainless steel, giving it better corrosion resistance.
Overall, 316 stainless steel offers the best quality and corrosion resistance and is the most expensive. It is followed by 304 stainless steel, while 201 stainless steel is the most economical option.
Our products are generally divided into two product ranges:
The cavities of some products are supplied with 304 stainless steel as standard.
Most KENTON products use 201 stainless steel as standard.
Products manufactured with 316 stainless steel are available upon request.
Galvanised steel is coated with a protective layer of zinc. This provides a certain level of rust resistance and protection against mild corrosion. However, its corrosion resistance cannot be compared with stainless steel, and it may still rust after extended use.
Carbon steel does not naturally resist rust or corrosion. Therefore, its surface must be protected using paint or electrostatic powder coating.
Galvanised steel is generally more expensive than carbon steel.
The cavities of KENTON series products are available in either 201 stainless steel or galvanised steel. The exterior cabinets are manufactured from carbon steel with a protective powder-coated finish.
Selection Tip:
For applications involving strong acids, alkalis or highly corrosive substances, 316 stainless steel is recommended. For general applications involving mild acids, alkalis or corrosion, 304 stainless steel is usually suitable. The material should be selected according to the level of corrosion expected.
Circulating air motors are normally used in environments with a wide operating-temperature range. Therefore, the motor bearings and heat-dissipation system must meet demanding performance requirements.
Motors designed for high-temperature operation are generally equipped with:
High-temperature-resistant bearings
A built-in cooling fan
A cast-aluminium housing for improved heat dissipation
Unlike standard commercially available motors, our motors are specially designed according to the specifications and operating requirements of each product series. Their structure, power output and other operating parameters are adjusted to ensure reliable performance under different temperature conditions.
The airflow circulation produced by the motor and fan blade also varies according to the size of the equipment. Different cavity capacities require different airflow volumes, so the motor and fan system must be correctly matched to the equipment.
The KENTON DHG and DNP series are equipped as standard with circulating air motors featuring high-temperature-resistant bearings, built-in cooling fans and specialised heat-dissipation structures.
Selection Tip:
For applications requiring high operating temperatures or long periods of continuous operation, we recommend selecting a motor with high-temperature-resistant bearings and an efficient heat-dissipation system.
Electric heating tubes are tubular heating elements. Common tube materials include:
Seamless 304 stainless steel
201 stainless steel
Carbon steel
The heating tube contains resistance wire, crystalline magnesium oxide powder and other components.
Compared with ordinary exposed heating wires, electric heating tubes offer:
Better overall performance
A longer service life
Easier maintenance
Greater resistance to damage caused by moisture, liquids or adhesive drips
Finned heating tubes provide higher thermal efficiency and more even heat distribution.
Seamless 304 stainless-steel heating tubes are formed by directly bending a continuous tube. They contain no seams or welded joints, providing better electrical insulation and improved corrosion resistance.
Heating tubes made from 201 stainless steel offer slightly lower performance, while carbon-steel heating tubes provide the lowest corrosion resistance of the three options.
KENTON series products are normally equipped with 201 stainless-steel or carbon-steel heating tubes. However, some products are equipped with seamless 304 stainless-steel heating tubes as standard, with finned heating tubes fitted to selected models.
Selection Tip:
For samples containing moisture or corrosive substances, seamless 304 or 201 stainless-steel heating tubes are recommended. Carbon-steel heating tubes are not recommended in these environments because corrosion may reduce their service life.
Products using exposed heating wires must not be selected for samples containing high moisture levels, adhesive, resin or other substances that may drip onto the heating element.
The controller is one of the most important components of the equipment. Common display and control systems include:
LCD controllers, with touchscreen options available
Digital controllers
Analogue pointer controllers
In terms of control accuracy, the general ranking from highest to lowest is:
LCD controller → Digital controller → Analogue pointer controller
In addition to the type of display and control accuracy, the overall performance and available functions of the equipment are determined by:
Precision electronic components within the control board
Temperature and humidity sensors
Intelligent control programs
Supporting software
Most products are equipped with LCD controllers as standard, providing a control accuracy of ±0.1°C.
Sensitive sensor components and critical precision-control components are imported. Multi-stage programmable software is also available as an optional feature. This software allows a computer to connect to and monitor up to 16 units simultaneously in real time.
Except for certain models, they are equipped with either:
Digital controllers with an accuracy of ±0.5°C; or
Analogue pointer controllers with an accuracy of ±1°C.
Digital controllers include PID control, which helps reduce temperature fluctuations and minimise temperature overshoot.
Analogue pointer controllers do not include PID control.
Selection Tip:
Customers requiring high temperature or humidity accuracy and good uniformity should select an LCD or digital controller.
For network connectivity, real-time monitoring or programmable operation, an LCD controller is recommended.
Analogue pointer controllers are suitable only for general applications. They may experience noticeable temperature fluctuations within the operating range and are therefore not recommended for laboratory testing or other precision applications.
Analogue pointer controllers also generally do not provide timer functions, over-temperature alarms or other advanced safety features.
For temperature-controlled equipment, national standards generally assess three main temperature-performance characteristics:
Controller accuracy
Temperature uniformity measured across nine points at the upper, middle and lower sections of the cavity
Temperature fluctuation at any individual measurement point
Therefore, using a high-accuracy temperature and humidity controller alone is not sufficient. The controller must work together with an effective cavity preheating system and a properly designed circulating air duct.
Preheating technology distributes heating elements around the cavity to preheat its walls evenly. Heat is then transferred throughout the cavity through thermal conduction and forced-air convection.
In general, the greater the number of heated surfaces, the better the temperature distribution.
The circulating air system combines:
The circulation motor
Fan blades or impellers
Air inlets
Air outlets
A specially designed internal airflow path
A properly designed airflow system helps maintain stable and uniform temperature and humidity throughout the cavity.
Air-duct designs may provide circulation from one, two, three or four sides. Generally, increasing the number of convection surfaces improves temperature distribution.
The appropriate air-duct design depends on the equipment grade, cavity capacity, internal structure and operating specifications.
Most products feature cavity preheating technology and multi-surface circulating air ducts, with a greater number of heating and convection surfaces.
The heating and airflow configurations of our products vary by model. Available designs range from one-sided to three-sided heating and from one-sided to three-sided circulating airflow.
Customers can select the most suitable configuration according to their operating requirements.
Selection Tip:
Customers requiring excellent temperature or humidity uniformity and low fluctuation should select products with cavity preheating technology and a greater number of circulating airflow surfaces.
For demanding applications, we recommend the higher-grade KENTON series products.
The quality of the insulation system directly affects:
Temperature fluctuation inside the cavity
Heat loss
Energy consumption
Overall temperature stability
Glass-fibre insulation can provide effective thermal insulation. However, because heat may still transfer between the cavity and the cabinet, a certain amount of thermal energy can be lost.
Some product uses a fully separated cavity and exterior-cabinet design.
The cavity is wrapped with imported thermal-insulation material, while a hollow isolation layer separates the cavity from the exterior cabinet. This structure helps minimise heat transfer and reduces thermal energy loss as much as possible.
Selection Tip:
Customers seeking improved energy efficiency and lower heat loss should consider products featuring a fully isolated cavity and high-quality insulation structure.
Temperature changes are mainly controlled through two processes:
Heating raises the temperature.
Refrigeration lowers the temperature.
Temperature-controlled equipment therefore uses two systems to manage changes in temperature.
The equipment must not only reach the set temperature, but also minimise fluctuation and maintain good temperature uniformity.
Balanced heating and refrigeration technology provides an effective solution.
During the cooling process, the refrigeration system and heating system operate simultaneously. The controller adjusts the operating time and output ratio of both systems to balance the amount of heating and cooling.
This allows the equipment to reduce the temperature while minimising the effect on temperature uniformity and fluctuation.
Balanced control technology can also help prevent frost formation caused by the continuous operation of the evaporator.
All full-temperature-range products are equipped with balanced heating and refrigeration technology as standard. They also feature:
Internationally recognised compressor brands
DuPont R134a environmentally responsible refrigerant
A manual refrigeration-capacity adjustment switch
Thickened copper pipes and evaporators
The refrigeration-capacity adjustment function helps the equipment meet demanding test conditions, including high-temperature and low-humidity environments or low-temperature and high-humidity environments.
The thickened copper pipes and evaporators improve durability and refrigeration performance.
Selected KENTON models are equipped with balanced heating and refrigeration technology. Standard KENTON models normally use domestic-brand compressors and R134a refrigerant.
Selection Tip:
Balanced heating and refrigeration technology provides improved control of temperature fluctuation and uniformity across both high- and low-temperature operating ranges.
During operation, the cavity of a vacuum oven is maintained under negative pressure.
If the tempered-glass door breaks, pressure may cause pieces of glass or the door assembly to rebound outward, creating a potential safety risk to the operator.
To reduce this risk, all Kenton vacuum oven doors feature a specialised dual-layer explosion-resistant glass protection design.
The doors are also equipped with spring-buffering mechanisms at all four corners. These mechanisms help absorb pressure and provide additional protection for operators.
Vacuum ovens operate under negative pressure. Therefore, the structural strength of the cavity is particularly important.
The cavities of all Kenton vacuum oven series are manufactured from 2.5 mm thick 304 stainless steel.
In addition, five sides of the cavity are reinforced with welded solid square-steel sections. This increases the cavity’s load-bearing capacity and helps prevent the cavity walls from deforming inward as the vacuum pressure increases.
Vacuum drying ovens transfer heat mainly through thermal conduction. Therefore, the number and position of heated surfaces directly affect temperature uniformity.
The DZF series offers several heating configurations.
The DZF-60 series uses heating tubes installed on both sides of the cavity. Heat is transferred from the heating tubes through the cavity structure.
This series is suitable for general constant-temperature applications in a vacuum or negative-pressure environment.
Each shelf in the DZF-30 series is equipped with an independent heating tube.
Heat is transferred directly through each shelf, and the temperature of each shelf can be set and controlled independently.
This series is suitable for applications requiring different temperatures to be maintained on individual shelves within the same vacuum environment.
The DZF-50 series provides heating from four sides of the cavity:
Left side
Right side
Rear side
Bottom
This multi-surface heating arrangement provides more even heat transfer and improved temperature uniformity.
Select the DZF-60 series for general constant-temperature applications under vacuum or negative-pressure conditions.
Select the DZF-50 series when improved temperature uniformity and lower temperature fluctuation are required.
Select the DZF-30 series when each shelf must operate at an independently controlled temperature within a constant-temperature vacuum environment.
