SU950292A1 - Preserve sterilization process and automatic control method - Google Patents

Description

(54) METHOD FOR AUTOMATIC CONTROL OF CANNING STERILIZATION PROCESS

one

The invention relates to methods for automatically controlling the sterilization process of canned food in an autoclave and can be used in the fish and canning industry.

There is a known method for automatically controlling the sterilization process of canned food, which consists in regulating the process according to the temperature and pressure inside the autoclave and measuring the pressure inside the sterilized can under the same conditions as the entire sterilized batch of cans 1.

The disadvantage of this method is that the supply of compressed air in small quantities dramatically worsens the heat transfer from the heating medium to the bank due to the occurrence of air spaces between the heating medium and the can wall, which leads to an increase in sterilization time and an increase in steam consumption.

Closest to the proposed technical solution is a method for automatically controlling the sterilization process of canned food, which includes the programmatic implementation of the blowing of the autoclave and the software control of the steam supply.

cooling water and compressed air in an autoclave 2.

The disadvantage of this method is that there is no provision for stabilizing the pressure difference between the pressure

5 inside the can and pressure of the autoclave, which leads to the deformation of the cans and the leakage, and therefore increases the steam consumption.

The aim of the invention is to reduce

, Q time of sterilization and steam consumption for heating products.

This goal is achieved by the fact that according to the method of automatic control of the process of sterilization of canned food, which involves the program implementation

15, the autoclave purge and programmed regulation of the supply of steam, cooling water and compressed air to the autoclave, purge the autoclave and supply air to it, taking into account the pressure difference between

2Q pressure in the can and pressure inside the autoclave.

The drawing shows schematically a device for implementing a method for automatically controlling a canning sterilization process.

The device comprises a batch autoclave 1, a cooling water supply line 2 with an adjustable valve 3, a compressed air supply line 4 with a control valve 5, a heating steam supply line 6 with a control valve 7, a purge line 8 with a control valve 9, an autoclave pressure sensor 10, a pressure sensor 11 inside the can, a temperature sensor 12, a subtraction unit 13, controllers 14-17 and a command-programming device 18 with a setpoint device.

The method of automatic control of the sterilization process is carried out as follows.

After the autoclave is loaded with canned goods, its lid is closed and the command-programming device 18 is switched on, which determines the time it takes for each sterilization stage to take place: purging, raising the temperature and sterilization itself and cooling. At the stage of purging, the programmer 18 sends a command to the controllers 15 and 16 to completely close the valves 5 on the compressed air supply line 4 and on the cooling water supply line 2, and to command the controllers 17 and 14 to open the valve 7 on the heating steam supply line 6 and valve 9 on line 8 purge.

At the stages of temperature rise and sterilization, valves 3 and 5 are fully closed. A signal proportional to the pressure in the autoclave from sensor 10 and a signal proportional to the pressure inside the can from sensor 11 are sent to subtraction unit 13, the signal of which is proportional to the pressure difference arrives at the input of regulator 14, which acts on valve 9, by changing steam flow through the purge line. Thus, the controller 14 maintains an overpressure in the autoclave as compared with a pressure inside the can equal to a predetermined allowable value. The signal from sensor 1.2, proportional to the temperature inside the autoclave, is fed to the input of the regulator 17, which acts on the valve 7 on the steam supply line, maintaining the temperature in accordance with the law of temperature variation set by the command-programming device 18

At the cooling stage, in accordance with the signal from the command and programming device 18, valve 7 is closed on the steam supply line and valve

9in the purge line. Signal from sensors

10 and 11 through the subtraction unit 13 enters the inlet of the regulator 15, which changes the air flow, acting on the valve 5 in such a way that the overpressure in the cans, compared with the pressure in the autoclave, is equal to the specified allowable value. The signal from sensor 12, proportional to the temperature in auto 1ave, enters the input of regulator 16, which, acting on valve 3, changes the flow rate of cooling water in the autoclave so that the temperature in the autoclave decreases in accordance with the setting of the command-programming device.

In the proposed method, both during the sterilization period and during the cooling period, the permissible mismatch between the pressure inside the can and the pressure in the autoclave is ensured. This makes it possible to accelerate (intensify) the heating process and the process of cooling the cans. At the same time, this effect is achieved without supplying compressed air during the heating period and the period of self-sterilization of canned food.

As a result of the implementation of the proposed method, the heating steam consumption at a given performance is reduced by 2.1% and the sterilization time is reduced on average by 0.

Claims (2)

1. USSR author's certificate number 345711, cl. A 23 L 3/00, 1969. 2. USSR author's certificate for application number 2908267/13, cl. A 23 L 3/00, 07.04.70.