Design a vertical periodic autoclave with a volume of 2.75 m ³ - course

Contents

Introduction

1. General information about the sterilization process

2. Arrangement and principle of autoclave operation

1.1. General information and classification of autoclaves

1.2. Autoclave basket

1.3. Bayonet shutter

1.4. Bayonet Ring Rotation Mechanism

3. Strength calculation of the apparatus walls

3.1. Calculation of cylindrical shell

3.2. Calculation of elliptical bottom

3.3. Calculation of elliptical cover strength

4. Strength calculation of holes

4.1. Calculation of single hole diameter not requiring reinforcement for cylindrical shell

4.2. Check of mutual influence of holes on cylindrical shell

4.3. Design diameter of single non-reinforcing hole for elliptical bottom

4.4. Check of mutual influence of holes on elliptical bottom..

4.5. Reinforcement of interconnecting holes on elliptical bottom

4.6. Design diameter of single non-reinforcing hole for elliptical cover

4.7. Check of mutual influence of holes on elliptical cover

5. Calculation of shell strength from impact of support loads

6. Calculation of counterweight weight

7. Bayonet shutter calculation

8. Thermal calculation

Conclusion

List of literature used

Applications:

1. Job for Course Project

2. Autoclave Assembly Diagram

3. Specifications

Introduction

The task of my course project is to design a vertical periodic autoclave with a volume of 2.75 m ³ (annex 1).

Autoclaves are intended for sterilisation of preserves. In the preservation industry, thermal sterilization is used as the main process to protect food products from damage, in which the product in a hermetically sealed container is subjected to heating to inactivate microorganisms. Recently, new methods of processing products have been proposed, also based on the suppression of the vital activity of microorganisms: ionization radiation, exposure to high-frequency currents, etc. However, it must be assumed that the thermal sterilisation of preserves in sealed containers will remain for a long time the main method of industrial production of preserves.

Sterilization is the heat treatment of preserves, the purpose of which is to suppress the vital activity of microbes at a temperature of 100 ° C and above, in contrast to pasteurization, which is carried out usually at a temperature below 100 ° C.

When sterilizing preserves, two factors are of primary importance - the temperature and duration of its effect: the higher the sterilization temperature, the shorter the time required to inactivate microbes, and vice versa.

The duration of exposure to temperature required to kill microbes at a given sterilization temperature is called "deadly time"; it depends on sterilisation temperature, chemical and physical properties of preserves, type and amount of microbes in the product. to be sterilized.

In this course work, I took pork as the sterilization product, since the temperature and duration of its sterilization is one of the largest, therefore, for other food products, the autoclave can also be used for sterilization.

In the autoclave, the heating temperature can reach 130 ° C, but can be controlled depending on the sterilization mode.

The working medium is water and saturated water vapor that heats this water. Steam is supplied using a barbater.

In this course work, I have to design an autoclave with the best characteristics, and most importantly, use a bayonet gate, and a manual mechanism for turning the bayonet ring, to quickly open the cover.

Arrangement and operation of the autoclave

Depending on the sterilization mode, the devices are classified into periodically and continuously operating ones operating at atmospheric pressure and above.

Autoclaves are made of two types: vertical and horizontal. Horizontal autoclaves are used for sterilizing preserves in tin containers, vertical ones for all types of preserves, both in tin and glass containers, so they are widely used in canning plants.

The autoclave includes the following components: housing, reinforcement unit, automation system.

The body of the autoclave designed to accommodate baskets with preserves during the sterilization process is a welded cylindrical vessel with an elliptical bottom, closed from above by an eleptic cover.

Housing and cover are provided with loops for attachment of heat insulation from outside.

The cover is connected to the housing by a bayonet ring.

To seal the autoclave in the plane of the connector, a flange is welded to the body, into the groove of which a rubber collar is installed .

Three supports for mounting the autoclave and trunnions for slinging are welded to the housing.

Connectors are welded to the autoclave body for connection of steam supply lines, water, compressed air, upper and lower drain and connection of safety valve, as well as instrumentation.

Inside the housing in the lower part brackets are welded to install baskets on them and a perforated annular bubbler is installed.

Drain branch pipe is welded to housing bottom.

Eyes for hinged connection with body, handle for cover opening and closing are welded to cover.

Operation of the autoclave can be carried out in program, automatic and manual modes, and sterilisation of preserves is carried out in steam or water media. The principle of operation is based on the effect of a high temperature sterilization medium on the product and its holding for a certain time.

Automation system is intended for automatic program control of process of preserves sterilisation in steam and water working media. It provides monitoring and recording of temperature and pressure in the autoclave during the entire sterilization cycle, as well as protection from emergency situations. The automation system, if necessary, provides for the possibility of manual control of actuating devices in place.

The automatic control system fully automates the process of sterilizing preserves, which allows:

Avoid overruling or overruling of the product due to timing errors and low accuracy during manual temperature control by the autoclave operator;

eliminate the possibility of irreversible deformation and failure of the covers due to low accuracy and low speed during manual pressure control by the autoclave operator;

increase the number of autoclaves controlled simultaneously by one operator;

reduced steam and air consumption due to high accuracy of temperature and pressure control.

Process control can also be carried out visually, using direct reading devices - pressure gauges and thermometers.

Autoclave basket.

Autoclave basket represents perforated cylindrical shell and perforated bottom. Ring is welded in upper part of shell to increase its stiffness. Vertical struts are welded to inner part of shell, suspension with spacer is pivotally installed in struts. The posts support the upper basket.

Suspension in closed position rests on stop welded to ring. Axes are welded on the ring, on which rollers are installed, which provide a guaranteed annular gap between the autoclave body and the basket.

Bayonet shutter.

The purpose of the gates and their basic requirements.

dace

When designing capacitive devices of periodic operation, it is very often necessary to deal with detachable fixed tight connections - flange, threaded, bayonet. The firmly dense nature of these compounds is due to the presence of pressure or vacuum in the apparatus.

Sealing of fixed detachable joints, saws, as they are still said, is achieved by compression of sealing surfaces with a certain force.

Of all the detachable fixed strong-tight joints used in the equipment industry, flange joints have become the most common.

In conventional flange connections, the required compression force is achieved by tightening the bolts or pins, which also absorb the pressure load in the apparatus. Flange bolts ensure proper strength, tightness and reliability. However, they are inconvenient when a relatively frequent connection connection is required. In these cases, especially in large apparatuses, it is advisable to use fast-acting locking devices to connect the cover to the housing, to which bayonet locks belong.

We consider it necessary to provide some clarity in the interpretation of technical terms: lock, lock connection or device, shutter, fast-acting shutter, bayonet shutter.

By the term "lock" or "lock connection" as applied to the subject matter is generally meant the connection of parts or parts of the apparatus under the influence of external loads or working environment in the apparatus. A typical flange connection is a type of lock and consists of two flanges and attachment parts (bolts or studs with nuts) connecting them.

Many authors refer to the closure as a sealing contact device that provides a lock, such as a flange joint, with density. Gate includes sealing surfaces of flanges and gasket compressed between them.

In the case of high-speed shutters of devices in general and bayonet shutters of devices in particular, the words "lock," "lock" and "connection" have become a broader and unifying concept: each of them can be used as equivalent in the same meaning when describing locking or sealing devices. So, for example, the phrases "Bayonet lock," "Bayonet gate" and "bayonet connection" have the same meaning, and each of them implies the whole set of properties of the connection. The authors prefer the terms "fast-acting shutter" and "bayonet shutter," which will mainly be used in the future.

The word "fast-acting" speaks for itself: such a shutter should ensure quick locking and unlocking of the lid and sealing of the connection. There is no distinction between the speed of these operations, when the shutter can be considered non-fast or fast, but in any case it can be said that the locking speed of the shutter unlock saw should be many times higher than with a conventional flange connection with a bolt attachment.

A characteristic feature that makes the shutter fast is the combination of all operations of opening and closing the lid in one or two. For example, a flange connection with flip bolts or struts, even when mechanizing the nut unscrewing process (by means of wrenches), is not fast-acting, since in principle it does not change the method of attachment of the lid. And the use of hydraulic cylinders to create the necessary seal (instead of bolts and nuts) allows you to activate all the clamping devices at the same time, which turns the shutter into a fast-acting one.

It should be noted that the method of removing the cover from the device (manually or by special lifting mechanisms) is not taken into account when classifying the gates as fast or normal. The criterion in evaluating the type of shutter is only the method of closing (locking) the lid. In addition, the difference in shutter speed may not always be expressed by significant values .

The bayonet gate is one type of fast-acting device. The term "bayonet gate" comes from the French word "baionnette," which means: bayonet (bayonet) lock, bayonet connection. Sometimes, therefore, the bayonet gate is called bayonet. In addition, the abbreviated name of the bayonet shutter - "bayonet," "which, in principle, does not contradict technical terminology and at the same time simplifies business communication at work.

Principle of operation

Cover flange connection with housing consists of housing flange, cuff, cover flange, bayonet ring and split ring.

To lock the cover, the bayonet ring rotates half the pitch of the tooth, overlapping the teeth of the cover flange. The surfaces of the ring teeth and the cover flange are flat, at the ends of the teeth there are special bevels (lead-in chamfers) that help to press the cover at the initial moment of ring locking.

To prevent displacement of bayonet ring from normal concentric position during its rotation and to reduce friction forces, bayonet ring is equipped with four built-in rollers fixed in housing. Position of rollers is controlled by bolts.

Bayonet ring is fixed by split ring and three rollers. Sealing of flange connector is performed by cuff.

Bayonet ring rotation mechanism.

The rotation mechanism is used to rotate the bayonet ring manually.

The body of the rotation mechanism consists of a hollow cylinder, which is bolted on a bracket welded to the body of the autoclave, two rollers are located in the body. Gear is rigidly fitted on roller to turn bayonet ring. Two sealing rings are located on the roller. The square end of the roller enters the square hole of the bushing with a swivel nut fixed in the housing allowing the bushing to rotate together with the roller relative to the housing. When it moves to the right, the roller engages with the roller, the roller is moved by compressed air, which is supplied from the pneumatic line to the housing of the rotation mechanism through the connector. When relieving the pressure, the spring must return the roller to the extreme left position, while the clearance between the teeth of the rollers should not be less than 4.. 8 mm. The gear does not rotate when the sleeve rotates. The rotation is manually transmitted to the gear by a swivel handle. You can install the extension lever on the swivel handle.