The Main Purpose Of Using Vacuum Furnaces Is To Heat

When selecting heating elements, it is also necessary to handle the chemical properties of the product according to one's own needs to avoid the material of the heating element affecting the quality of the workpiece. Therefore, the vacuum furnace needs to select heating elements reasonably.

The commonly used heating elements in high vacuum sintering furnaces include graphite and stainless steel.

Graphite heating element: Graphite has characteristics such as high temperature resistance, small thermal expansion, and strong resistance to thermal shock. Its mechanical strength increases with the increase of crushing temperature below 2500 ℃, and is best at around 1700 ℃, surpassing all oxides and metals. Graphite materials have a high melting point and low vapor pressure. The atmosphere of a vacuum furnace contains low concentrations of carbon, which reacts with oxygen and water vapor in the residual gas to produce a purification effect, greatly simplifying the vacuum system and reducing costs. In the production process of vacuum furnaces, the heating element commonly used for heat treatment is graphite, including its furnace bed support, insulation screen, connecting plate, connecting nut, ventilation pipe, etc.

Stainless steel heating element: small size, high power, fast thermal response, high temperature control accuracy, high comprehensive thermal efficiency, wide application range, strong adaptability, high heating temperature, long service life, and high reliability. High degree of mechanization, can be bent into various shapes according to customer requirements, lightweight, and easy to disassemble. Simple structure, low material consumption, low cost, long service life, high heat conversion rate, and energy-saving.

The reason why vacuum furnaces cannot extract clean air:

In regular experiments, if there is liquid present, a process of liquid evaporation is required (which can vaporize without heating under high vacuum). This part of the liquid can be vaporized by pulling the vacuum for a long time to achieve high vacuum stability. If the target air pressure cannot be reached for a long time, it is necessary to consider the system and the Roots pump. You can directly measure the maximum vacuum of the Roots pump (without connecting to other systems). If it is intact, it is the sealing performance of the system.

Vacuum furnaces are suitable for use in radiator heating systems.

The design temperature of the heat medium for a radiator hot water heating system is generally determined based on principles such as thermal comfort requirements, system operation safety, and economy. The water supply temperature should not exceed 95 ℃ to ensure that the heat medium does not vaporize under normal pressure conditions. Previously, the supply and return water temperature was often set at 95 ℃/70 ℃. However, in recent years, based on advanced heating experience both domestically and internationally, reducing the temperature of the heating medium appropriately is beneficial for improving comfort, so 80/60 ℃ is often used. The vacuum hot water boiler meets the requirement of 80/60 ℃ inlet and outlet water temperature in the design of the radiator heating system. Nowadays, residential buildings heated by urban heating networks or centralized boiler rooms in residential areas, even if the design water temperature is 95/70 ℃, when the outdoor temperature reaches the design, the operating water temperature is generally only about 70/55 ℃ to ensure the design indoor temperature. The main factors that determine the efficiency of heat sinks are the heat dissipation area of the fins and the flow rate of the medium inside the fins (which is not closely related to the temperature of the medium), and the same amount of heat carried by the same circulating water with the same temperature difference. The main difference between vacuum hot water boilers and traditional boilers (95/70 ℃) in radiator heating systems is that the heating time of the room is 4-5 minutes slower than that of traditional boilers.