Vertical autoclaves are made with two- and four-mesh, differing only in the height of the body.
The double-mesh vertical autoclave of the AB-2 brand of the Batumi Machine-Building Plant (Figure 1) has a welded cylindrical body made of carbon steel St. 3. The tightness of the connection between the lid and the body is ensured by a gasket made of oiled asbestos. Inside the autoclave there is a bubbler located above the bottom. Steel mesh with holes on the entire side surface is installed on the support ring. A purge valve is installed on the lid of the autoclave. A ring shower is installed under the autoclave lid. The water drain pipe is attached to the bottom of the autoclave in the center. A box is welded to the cylindrical part of the autoclave, on which a thermometer (up to 150°C), a pressure gauge (up to 0.6 MPa) and a safety valve are installed. To circulate water in the box, it is connected by a tube to the bottom of the autoclave; This ensures that the thermometer reads correctly.
The Batumi Machine-Building Plant produces autoclaves in which the lid is pressed to the body with a special clamp (instead of several wing nuts), which facilitates the work of autoclave operators and reduces the time for closing and opening the autoclave lid.
On the body of the autoclave and on the lid there are rings (flanges) of a trapezoidal section, between which there is a

A-grade AB-2: 1 - autoclave body; 2-autoclave lid; 3 and 4 - rings (flanges); 5 - sealing gasket; 6 - belt clip; 7 - segments; 8- outer belt of the autoclave; 9 - counterweight; 10 - grids; 11- bubbler for supplying steam; 12 - bottom, b - AB-4 grade; 1- support; 2 - bandage; 3 - circulation tube; 4 - instrument box; 5 - air valve.
Figure 1 - Vertical autoclaves

Sealing gasket. The quick-release belt clip has 15 sector grips (segments) mounted on a ring made of spring strip steel, and a lever system for tightening and spreading the clip. When the lever is turned, the belt clip tightens the segments. The segments, converging, enter with their internal cutouts into the protrusions of the rings and press the lid against the autoclave body. The outer belt limits the movement of the segments and holds them in a certain position when the lid is open.
The communication diagram of one autoclave is shown in Figure 2. As can be seen from the diagram, autoclaves for sterilization with back pressure, in addition to the usual pipelines, also have a pipeline supplying compressed air (usually through a bubbler for steam), or a pipeline for water supplied under pressure by a centrifugal or steam pump. In addition, a pipe connected to the sewage system extends from the upper part of the autoclave body.

1,2 and 4 - pipelines; 3 - centrifugal pump; 5 - compressor; 6 - compressed air receiver.
Figure 2 - Autoclave communication

The pipelines supplying steam and water to the autoclave have check valves; they prevent the movement of water from the autoclave into the network if the pressure there decreases. Two shut-off valves are installed on the steam-conducting pipe.
Before work, check the condition of the autoclave, the serviceability of all valves, instrumentation and gaskets.
Sterilization of canned food in tin containers in a steam environment is carried out as follows. Using an electric hoist, load baskets with jars into the autoclave, close the lid and use a belt clip to press the lid to the autoclave by turning the lever. Then open the purge valve and steam valve; the air is displaced by steam from the autoclave. When a stream of steam appears from the blow-off valve, close it and continue heating to the set temperature in the autoclave. The heating duration is set by the sterilization mode. The rate of temperature increase is controlled by supplying steam to the autoclave. Once the sterilization temperature is reached, it is maintained during the entire sterilization time, monitoring with a thermometer and regulating the supply of fresh steam.
After the sterilization time has expired, the steam valve is closed and the pressure and temperature are gradually reduced, releasing steam through the blow-off valve for the time specified by the sterilization mode. The jars are then cooled. To do this, the autoclave is fed under pressure. cold water or the grids are unloaded from the autoclave and the jars are cooled under a water shower or in air. The jars are cooled to a surface temperature of 40-45° C. If they are not cooled, the product in the jar continues to boil. When cooled to more low temperatures jars do not dry out and may become rusty.
Sterilization of canned food in glass jars in water with water back pressure is carried out as follows. Filled baskets are loaded into an autoclave filled with water, the temperature of which differs by 10-15 ° C from the temperature of the cans. The lid is hermetically sealed and the autoclave is filled with water, leaving a small air gap. The layer is a buffer that prevents sudden pressure fluctuations when some of the water is released. Then steam is supplied to the autoclave, gradually increasing the temperature and pressure in it to the set values.
The pressure in the autoclave increases due to the condensate formed from the steam. If the pressure in the autoclave becomes higher than permissible, and the temperature has not yet reached the desired value, then the pressure is reduced by carefully releasing part of the water through the drain pipe.
The set temperature is continuously maintained during the entire sterilization time, while simultaneously maintaining constant pressure in an autoclave. After sterilization is complete, the jars are cooled. To do this, cold water is introduced into the autoclave from above and the same amount of water is released through the drain pipe.
Studies have shown that when cooled, the heat resistance of beets is significantly lower than when heated. This is explained by the fact that when heated, the outer layers of the wall of a glass jar experience compressive forces, and when cooled, tensile forces arise in them, as a result of which cracks occur and the jars are destroyed. As experience shows, the most dangerous stage is the stage of cooling the cans from the sterilization temperature to 70° C. In this temperature range, especially high voltage, sometimes leading to their destruction. To prevent cans from breaking during cooling, the temperature in the autoclave should decrease gradually and evenly. To do this, cooling water is supplied in small streams through a bubbler or shower mounted under the lid of the autoclave. This method showed good results in factory conditions.
When the temperature in the autoclave approaches the final temperature, the pressure is gradually reduced while cooling continues. At the end of cooling, close all valves, open the blow-off valve or drain pipe and bring the pressure in the autoclave to atmospheric. Then some of the water is released and the baskets with cans are unloaded.
Devices for loading autoclave nets with cans and unloading them from the nets significantly facilitate the work of workers, increase labor productivity and reduce can breakage. The easiest way to load cans into nets is to load using a water cushion. In this method, an empty mesh is immersed using an electric hoist into a vessel with water, the level of which is slightly higher than the edge of the mesh. From the conveyor, the cans are fed into water, which protects them from deformation or breakage. When the mesh is filled with jars, it is unloaded from the vessel with water and loaded into the autoclave.
To unload the meshes after sterilization, the same vessel can be used, but filled with a solution whose specific gravity is greater specific gravity cans.
To load cans into meshes and unload them from meshes, installations with a hydraulic lift, as well as with an electromagnetic head, are also used.
The quality of canned food and the possibility of their long-term storage largely depend on the accuracy of the sterilization regime. The most reliable are automatic control and automatic regulation of the temperature in the autoclave and the duration of the sterilization itself. In periodic autoclaves, various automatic schemes are used to regulate and control the increase in pressure and temperature, the duration and temperature of the sterilization itself, automatic purge of air from the autoclave, back pressure, the duration of pressure reduction and cooling with water.
For automatic control and regulation, pneumatic and electric program thermostats are used using a time relay, sound and light alarms, with automatic recording of temperature and pressure in the autoclave over time.
When sterilizing canned food in tin and glass containers with steam in a periodically operating autoclave operating with back pressure, program temperature and pressure controllers of the PRP-2 and PRP-2U systems are used. These regulators provide a stable sterilization process according to a given mode with a temperature deviation from the set one of ±1.5° C.
Horizontal autoclave. The autoclave body (Figure 3) is installed in a horizontal position on feet.

1 - body; 2 - cover; 3-clamping steering wheel; 4-Sgrboter.
Figure 3 - Horizontal autoclave

The end sides of the housing on one or both sides are hermetically sealed with hinged lids. Inside the autoclave there is a bubbler for supplying steam and rails along which carts with cans move. Horizontal autoclaves are built for one, four and six trolleys; They differ from each other only in the length of the body. These autoclaves are equipped with the same instrumentation and communications as vertical autoclaves.
For horizontal autoclaves (as opposed to vertical ones; no channels (shafts) are required when installing them, as well as monorails with electric hoists or cranes for loading cans. The presence of lids allows you to load the autoclave on one side and unload it on the other side; this ensures some flow of movement cans, especially if the autoclave is loaded in the sterilization workshop and unloaded at the warehouse finished products. However, horizontal autoclaves take up a large area and it is difficult to sterilize canned food in water; in addition, the utilization rate of their volume is less. Studies have shown that with less sterilization time, the quality of canned food is higher.

Vertical autoclaves AV-2 AV-4

Long-term preservation of canned food without spoilage is achieved by suppressing the vital activity of microorganisms in them, which can be done various methods, of which the most common method is heat treatment (in some cases it is also a culinary heat treatment of raw materials).

Sterilizers are intermittent and continuous action They are vertical and horizontal. In some autoclave designs, the jars are stationary during the sterilization process, while in others (for example, horizontal rotary ones) they move to increase the rate of heat transfer.

The process of suppressing microflora in a product at temperatures up to 100°C is called pasteurization, at 100°C and above - sterilization. The equipment used to carry out these processes is called pasteurizers and sterilizers, respectively. Sterilizers can be used intermittently or continuously. Batch sterilizers are usually called autoclaves. They are vertical and horizontal. In some autoclave designs, the jars are stationary during the sterilization process, while in others (for example, horizontal rotary ones) they move to increase the rate of heat transfer.

In the factories of the USSR, and later in Russia, the most common vertical autoclaves were AV-2 and AV-4.

Continuous sterilizers are divided into hydrostatic, rotary and conveyor. Of the continuous hydrostatic sterilizers in the country's canneries, the OHS-1 "Hunister" (Hungary) and A9-FSA devices were most often used. For pasteurization individual species for canned food, belt or conveyor pasteurizers (A2-KPO, A9-KSZH) and plate pasteurizers were used.

Design of vertical autoclave.

Vertical autoclaves AB-2 and AB-4 are used for both sterilization and pasteurization of canned food in sealed containers. Included with them is the installation of software sterilization regulators in the autoclave, which allow automating the process.

The vertical autoclave AB-2 (Fig. 1) consists of a body 4, a cover 1 with a counterweight 12, a quick-release belt clip 2. The autoclave body is welded from sheet steel 6 mm thick
on the shell and 8 mm on the bottom. It rests on support beams or racks with paws 5. Inside the body, in the lower part, supports are welded for installing the autoclave basket. Even lower, in the cavity of the bottom, there is a bubbler 6. Steam enters it through pipe 7. Water is drained from the autoclave through pipe 8. Very often, the hole in the center of the bottom above pipe 8 is closed in factories with a metal mesh to prevent it from entering the fittings on the drain line. small broken glass.

Rice. 1. Autoclave AB-2

A pressure gauge box 10 is welded to the outside of the housing shell, connected by a circulation pipe 9 to the lower part of the autoclave. A sleeve for installation is welded into the pressure box
it contains 11 thermometers, covered with a protective casing. In addition, the box contains fittings for connecting pressure gauge 16 and connecting to the sterilization program controller.

In the upper part of the body there are pipes through which the autoclave is filled with water and drained if there is excess.

On the hinged spherical lid 1 there is a safety valve 13 and a test-drain valve 15. Under the lid there is a ring bubbler, which serves for uniform cooling of the cans with the product after sterilization. Water enters the ring bubbler from the main through flexible hose, attached to pipe 14. A counterweight with a weight connected to the lid serves to facilitate its opening and closing. The flanges of the cover and body are pressed tightly against one another by fifteen sector grips mounted on a ring made of spring strip steel. The ends of the belt clip 2 are tightened manually using a lever system.

To prevent the autoclave lid from opening under pressure, it is equipped with a safety device 3, consisting of a body, a piston, a glass, a rod, a gasket and a drain valve. Frame safety device connected to the autoclave by a pipe on flanges. The drain valve is screwed into the body from below, the glass - from above.

Inside the glass there is a piston connected to a rod. When the pressure in the autoclave increases to 0.005 MPa, the piston with the rod rises and the rod locks the handle of the clamping device. Due to the unreliability of the safety device, mechanical locking devices (for example, such as a spring-loaded rifle bolt) are manufactured and installed on autoclaves in factories.

Metal baskets, which are perforated cylindrical shells with welded or removable bottoms, are loaded inside the autoclave using an electric hoist.

A steel rod beam is attached to the top of the basket, by which the basket is grabbed by a hook. The ridges located on the upper edge of the shell provide clearance between the bottom of the upper basket and the cans in the lower basket.

Technical data of autoclaves AB-2 and AB-4 are given in the table below:

Indicators	AV-2	AB-4
Autoclave capacity, m3	1,57	2,75
Internal diameter, m
Limit operating pressure, MPa	0,35	0,35
Number of carts loaded
Dimensions, mm
width	1350	1350
length with lid closed	2200	2200
length with lid open	1870	1870
height with lid closed	2410	4000
height with lid open	3290	4790
Autoclave weight, kg
without baskets		1317
with baskets	1150	1750

To prevent lids from falling off glass jars and deformation of large-capacity tin containers or those made of thin tin, the necessary pressure of the working medium is created in autoclaves, and therefore electric-driven pumps and an emergency steam pump (in case of a power outage) should be installed in the autoclave compartment.

In accordance with OST 18-344- 79 autoclave baskets are equipped with springs to fix the rocker arm at an angle of 60°. The springs are selected so that the rocker arm of the suspended basket is in a vertical plane, and wheninstallation of the basket on the basket (in an autoclave) was adjacent under the weight of the upper baskets.

A mercury glass thermometer on an autoclave must have a scale of up to 200°C,pressure gauge - up to 0.6 MPa (6 kg/cm2).Autoclaves are installed strictly vertically in pits 2.2 m deepfor AB-2 and 3 m for AB-4. The distance between the centers of autoclaves in one row must be at least 2 m, between rows - at least 3.5 m.

With double row location of autoclaves, it is recommended to mount them with the front part towardsaisle (No counterweights should extend into the aisle). The shell of the housing protrudes above the floor by 0.8 m. The pit is equipped with supply and exhaust ventilation.The water is drained from the autoclave with a mandatory break in the stream.

OPERATION 1 VERTICAL AUTOCLAVE “AV-2”

Technological task: heat treatment (sterilization) of canned food.

Goal of the work: Assess the technical level (condition) of the vertical autoclave “AV-2” and make proposals for the development of its design to increase the efficiency of the sterilization process.

Job objectives:

1. Study the structure and operating principle of the vertical autoclave "AV-2".

2. Consider the features of the sterilization process.

3. Determine the theoretical and experimental performance, as well as the power of the heaters of the vertical autoclave “AV-2” at various modes work and process test results.

4. Give suggestions for maintenance vertical autoclave "AV-2".

5. Understand the rules for safe operation and adjustment of the vertical autoclave "AV-2".

Equipment, tools and inventory: vertical autoclave AB-2, clock, technical scales with weights.

Products: canned food in tin cans total volume 6.0 l.

Study of the device and principle of operation

The vertical autoclave AB-2 (Fig. 5.9.1) is intended for sterilization of canned food in mini-production conditions.

The autoclave consists of 11 sterilization and 4 water-steam chambers, which are a single structure welded from two insulated containers. The sterilization chamber is closed from above by a lid 12, equipped with a clamp 14 in the center from the outside and having slots along the periphery for the passage of clamps 14 (screws with flywheels). A water indicator column 7 with an upper 8 and a lower 3 taps is connected to the water-steam chamber in its upper and lower parts by fittings.

Fig.5.23. Vertical autoclave AB-2:

1 - casing; 2 - hose; 3, 8 - lower and upper taps; 4, 11 - water-steam and sterilization chambers; 5 - bottom; 6 - cassette for canned food; 7 - water indicator column; 9 - funnel; 10 - shelf; 12 - cover; 13 - pressure and vacuum gauge; 14 - clamp; 15 - electric contact pressure gauge; 16, 22 - ejection and filter valves; 17, 20, 23 - water, steam, condensate valves; 18 - ejector; 19 - safety valve; 21 - filter; 24 - bolt for fastening electric heating elements; 25 - box; 26 - electric heating element; 27 - electrical panel; 28 - switch; 29 - signal lamp

A funnel 9 is installed above the top tap, and a rubber hose nipple 2 is screwed onto the bottom tap. Above the bottom 5 of the sterilization chamber is the bottom tap of the cassette 6 with sterilization objects.

A pressure-vacuum gauge 13 and an electric contact pressure gauge 15, as well as an ejector 18 with valves 16 and 17 are connected to the upper part of the chamber using fittings. At the bottom it is equipped with a block with a condensate valve 23, a filter 21 and a filter valve 22. Safety valve 19 is connected to the upper part of the steam-water chamber, which is connected through a pipe with a steam valve 20 to the sterilization chamber 11. The autoclave is equipped with a protective casing 1, supported by three supports. On the casing at the bottom there is a box 25 that covers the terminals of the electric heaters 26 and their fastening bolts 24. The electric heaters are located in the lower part of the water-steam chamber, under the bottom of the sterilization chamber. An electrical panel 27 with a switch 28 and a signal lamp 29 is attached to the wall next to the autoclave on the side opposite the safety valve.

The autoclave operates as follows.

Load cassettes 6 with canned food into the sterilization chamber (it is recommended to carry out the first loading into a preheated autoclave). Close the lid of the sterilization chamber 12, lift the screw clamps 14 and tighten them tightly with the handwheels.

Turn on the electric heaters by turning switch knob 28 to the ON position (the signal lamp 29 should light up). After reaching the required pressure in the water-steam chamber, open steam valve 20, displacing air along with part of the steam through the previously open condensate valve 23. After 2...3 minutes, close valve 23. Then wait until the upper value of the sterilization pressure is reached on the electric contact pressure gauge 15, record the start time of sterilization. During sterilization, it is necessary to open valve 23 2-3 times for 10...15 s to remove condensate from the sterilization chamber, as well as to better wash the objects being sterilized with steam. After the specified sterilization time has elapsed, close valve 20, open the three-way valve of the pressure vacuum gauge and vent the siphon tube, release steam and condensate from the sterilization chamber by opening valve 23, and drain the sterilized canned food. To do this, open valve 17 for water inlet into ejector 18 and valve 16 for suctioning steam from the sterilization chamber. Carry out the ejection for 10 minutes, while the vacuum measured by pressure and vacuum gauge 13 should reach at least 44 kPa. At the end of the ejection, close valve 16, then valve 17 and open valve 22 to connect the sterilization chamber to the atmosphere, open lid 12, close valve 22 and unload the canned food.