HPP Machine Process At Glance

How does HPP Machine Process works ?

HPP machine is an industrial equipment for the food industry. It is used to process fresh products in order to increase their shelf life. How does it work ? Learn about HPP machines at glance.

Incredibly High Pressures

high pressure living condition
Hard living conditions Oceanic Abysses

HPP machines recreate the hostile living conditions of the ocean abysses. By applying pressure in all directions uniformly for about one to three minutes pathogens are killed or inativated.

But HPP foods retain their shape.

Necessary Energy Utilities

As many industrial equipments, HPP are an electrical machines. They are controlled by an HMI (Human Machine Interface). Unlike treatment machines with heating, HPP machines do not have a heating system. Only hydraulic mechanisms are used.

Pressure is made through air, water and oil. Only water is in contact with the treated products in the pressure vessel. To run a machine, you only need :

What you need ?
Quality Tap Water
Hydraulic Oil
Electricity Power
Compressed Air
Internet Connection

Footprint on floor and Space needed

HPP machines are not a huge machines. The smallest machine is six meters long. But you must plan space for loading and unloading conveyors and workers. The biggest machine is 10 meters long.

For the smallest machine you will need a rectangular area of 30 square meters, only for the HPP machine.


High Pressure Schema
HPP Process Diagram – Credit : Uhde High Pressure Technologies GmbH

Process Flow

How does HPP works, High Pressure Machine
HPP Machine Working

HPP machine processes only packaged products. This is not an aseptic process.

  • Depend on machine type, products are loaded manually in baskets or automatically with loading and unloading conveyors.
HPP conveyors loading
Loading HPP

Nota : Only one HPP machine in the market is fully automated. Concerning this machine, none handling man is needed. Loading and unloading are automatic.

  • As soon as the basket or automatic loading conveyor are full, the products are automatically brought into the pressure vessel.
HPP basket loading

Products are cooled before entering in the vessel.

  • The pressure vessel is closed with high-strength caps.
  • When the pressure vessel is locked, the processing cycle begins.
  • The vessel fill and pressure rise up by means a medium-pressure pump and by means of pressure intensifier. The pressure gradually increases in the vessel up to 6,000 bars.

Pressurization increases temperature by around 18° C.

high pressure processing
HPP Process
  • Pressure is applied both immediately and evenly spread leaving no evident crushing effect on the products.

Products are compressed around 16% in their packaging.

  • After a few seconds, the pressure is suddenly released – Fast depressurization of the vessel.
  • Caps are removed, the vessel opens and the products come out.

Cycles can range between 40 seconds to 3 minutes 45 seconds. The cycle is predefined by HMI system and pressure can be maintained for a time as you want.

hpp fast depressurization

At the end, the water is drained and the vessel is unloaded, and the machine is ready for the next round of high pressure processing.