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Utilizing Autoclave System for Sterilization

Types, functions, and components of the autoclave system with an example of design and sizing of a pressurization group

Autoclave systems ensure access to running water at the right pressure even in environments where the optimal situation could be compromised. In condominiums, for example, the presence of an autoclave is often essential to ensure the correct functioning of the water system and the living comfort for all tenants.

In this article, we will explore in detail the various types of autoclave systems, their components, and their advantages, providing a comprehensive overview of this important device.

What is an autoclave system

The autoclave system is a system that ensures access to running water even in situations where the water pressure is too low. This device is designed to automate the start and stop of one or more electric pumps, ensuring a sufficient water flow at an adequate pressure to serve utilities that would otherwise be without it.

In simple terms, the autoclave system works by increasing the water pressure inside the building’s pipes, allowing water to reach even the upper floors. This is particularly important in residential contexts, such as condominiums, where low water pressure could compromise the comfort and livability of the inhabitants.

Furthermore, the autoclave system is widely used in other situations, such as private homes or commercial buildings, where low water pressure could be a problem.

What are the components of the autoclave system

In a generic autoclave system, we can identify the following components:

  • autoclave chamber – typically made of stainless steel to ensure optimal resistance to corrosion and pressure. This structure is designed to withstand extreme temperature and pressure conditions without compromising the integrity of the materials processed inside it;
  • heating system – another crucial element of the autoclave system, it can take various forms depending on the specific application needs. It could consist of electric resistances, steam, or other heat transfer means, whose goal is to increase the temperature inside the autoclave chamber to activate the material treatment process;
  • pressure and temperature controls – essential to ensure safe and effective treatment of materials inside the autoclave. These devices constantly monitor the conditions inside the autoclave chamber and adjust the process parameters accordingly, ensuring that the pressure and temperature remain within the preset limits for the entire treatment cycle;
  • pressure vessel – also known as a bladder tank, is an essential element of the autoclave system where an air chamber is present. This bladder tank acts as an accumulator, allowing the pump to extend the operating period over a longer time, thus reducing the number of starts and stops, which can cause wear and dangerous water hammer effects;
  • pressure switch – turns on the pump when the water pressure drops below a certain limit and turns it off when it reaches the preset maximum value. These additional components help ensure the correct operation and safety of the autoclave system in various situations and applications.

In addition to the main components described above, an autoclave system may also include other elements to complete the system. For example, there may be a water storage tank to store a certain amount of water coming from the network, along with an electric pump, usually of the centrifugal type, to push water into the pressurized tank.

The water tank can be sized using the following formula:

V = 30 (Gpr60) / a ⋅ (Pmax+1) / (PmaxPmin)


V = Autoclave volume, [l]
Gpr = Design flow rate, [l/s]
Pmin = Min. overpressure, [bar]
Pmax = Max. overpressure, [bar]
a = Maximum hourly pump starts [h-1]

Types of autoclave systems

Autoclave systems can be divided into different types based on automation systems, mainly into two categories with the following subcategories:

  • system with pressurized tanks
    • classic autoclave
    • autoclave with membrane tanks
  • inverter system
    • pure inverter system with control of one or more pumps
    • pure inverter system with an inverter for each pump
    • mixed inverter system

System with pressurized tanks

This type of system has two main variants:

  • classic autoclave
  • autoclave with membrane tanks

Classic autoclave

The classic autoclave consists of one or more tanks, two or more pumps, a compressor, an electrical panel, and the necessary instruments for the operating logic.

The operating logic is based on the compressibility of air. In the tank, located downstream of the pumps, water and air are simultaneously introduced automatically. The automation is ensured by pressure switches, one for each pump and one for the compressor, which regulate the process. When utilities draw water, the pressure inside the tank decreases, activating the pumps to maintain the desired pressure. The pumps provide water at the minimum pressure set to meet the users’ needs. Once the maximum level in the tank is reached, the pumps stop. The compressor ensures that the air level in the tank is constantly optimal.

System advantages

  • Extended autonomy guaranteed by the tank size, allowing rest periods for the equipment.
  • Operational simplicity and durability guaranteed by the efficiency of the electromechanical equipment.

Autoclave with membrane tanks

This type of system consists of membrane tanks, two or more pumps, a control panel, and the instruments for the operating logic.

The operating logic is similar to that of the classic autoclave but lacks the compressor. The tank sizes are limited, so autonomy is reduced. Periodic restoration of the air cushion must be done manually. This system is characterized by cost-effectiveness in purchase and installation but requires more frequent maintenance due to limited autonomy and component quality.

pressure control system

Pressure control system

Inverter system

The inverter system can be divided into three main types:

  • pure inverter system with control of one or more pumps
  • pure inverter system with an inverter for each pump
  • mixed inverter system

Pure inverter system with control of one or more pumps

This system consists of one or more pumps, a control panel with an inverter, a pressure transducer, and an anti-surge tank.

The operating logic is based on the pressure transducer, which detects pressure variations caused by utility usage. The inverter controls the pumps according to consumption needs, allowing efficient and silent operation. The anti-surge tank prevents continuous pump restart in the presence of small system leaks.

System advantages:

  • Energy savings thanks to the motor speed regulation of the pumps;
  • Increased silence and reduced equipment wear.

Pure inverter system with an inverter for each pump

In this type of system, each pump is controlled by a separate inverter. The operating logic is similar to the previous system, but both pumps operate at variable speeds and switch periodically.

System advantages:

  • Same efficiency and silence as the previous system, but with greater operational flexibility.

Mixed inverter system

This system combines the advantages of the classic autoclave system with those of the inverter system. One pump is controlled by the inverter, while the others are controlled by pressure switches. The tank is larger than in other systems and does not have a membrane.

System advantages:

  • Silence ensured by low motor speeds and reduced equipment wear;
  • Robustness and reliability of the electromechanical system;
  • Possibility of longer pump rest periods due to the tank size.

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