Course project "Designing a pit chamber"

Contents

Introduction

1. Characteristics of manufactured products

2. Demand Program Calculation

3. Selection and justification of production technology

4. Description of processes occurring during maintenance

5. Installation design features, principles

organization of its heat supply

6. Constructive calculation

7. Heat Engineering Calculation

8. Through Cyclone Size Selection

9. Safety Solution

10. Technical and economic indicators

Bibliographic list

Introduction

One of the main components of the technology of the construction industry is heat treatment, which spends about 30% of the cost of producing building materials and products. In addition, heat treatment consumes about 80% of the fuel and energy resources consumed for the entire production cycle.

Currently in Tyumen at the plants for the production of reinforced concrete products. such as ZHB1, ZHBI-5, DSK, etc., periodic installations for thermal moisture treatment, operating at normal atmospheric pressure, the basis of which are pit chambers, are common. They are used mainly for thermal moisture treatment of medium-sized reinforced concrete products: various slabs, panels, small blocks, etc.

The actual coefficient of full use in many of them does not exceed 25-35%, the rest is different losses, most of which are due to heating of enclosing structures and imperfect sealing of chambers. However, the use of modern construction heat insulation materials will reduce losses and significantly increase efficiency.

In addition to increasing the efficiency of units for reinforced concrete products, it is necessary to carry out measures to improve the process itself. Heat treatment to some extent reduces the physical and chemical properties of concrete, compared to those that it would acquire, hardening under normal conditions in a wet environment. This is due to the violation of the concrete structure during heat treatment. Nowadays, these problems can be solved by insulating concrete in a thermal installation with special coatings, polymeric materials, emulsions. Also, the minimization of undesirable formations can be ensured by using modern electronic equipment with the installation, which would provide a clearer control over compliance with technological parameters (humidity, temperature).

In this way, the pit chambers are quite simple and efficient heat treatment devices with all requirements and modern technological solutions.

Characteristics of manufactured products

Article dimensions:

length 5980 mm

width 2980 mm

140 mm thick.

Article volume 1.48 m3

Metal consumption per 1m3 - 53.73 kg

Weight of the article 3702 kg

Concrete grade B12.5

Expense on 1 CBM of concrete: C of =400 kg, B=190 of l, A=80 of kg, Shch =1240 kg,

P = 590 kg.

Expense on 1 product: C of =592 kg, B=284 of l, A=118 of kg, Shch =1835 kg,

P = 873 kg.

Structural features of the plant, principles of its heat supply organization

Yam-type cameras are used both at factories and at landfills. Depending on the operating conditions, the level of groundwater, the chamber is either buried in the ground, so that its edges rise above the floor of the workshop 6070 cm or are installed above the field level. The chamber has a rectangular shape, they are made of concrete or reinforced concrete. Walls of chamber are equipped with heat insulation to reduce heat loss into environment. Floor of chamber and covers are made with slope for condensate drain. There is a condensate discharge track in the floor. Walls of chamber have hole for introduction of heat carrier, which is supplied downwards of chamber through pipeline from network. The pipeline ends with perforated pipes laid along the perimeter of the chamber. In addition to the hole for the introduction of coolant in the wall of the chamber, a hole is made, gates are used to ventilate the chamber.

Articles are loaded into moulds by means of support posts with crane. Each mold from the next is insulated by metal gaskets so that steam heats the molds from all sides. The height of the chambers reaches 2.53 m. The width and length are chosen taking into account the placement of products in stacks. Clearances are arranged between stacks and walls of chambers to provide grips of articles with automatic crossarms during unloading and loading of articles. When the article is placed on the lower bracket of the support posts due to gravity, the next bracket opens, allowing the articles to be loaded to the entire height of the chambers. After loading, the chamber is closed by a cover representing a metal frame filled with heat insulation material or a slab of light concrete.

A water seal is used to seal the cover. To do this, a channel is installed on the upper sections of the chamber walls, and the cover along its perimeter is equipped with an angle that enters the channel: The channel is filled with water, in addition, condensate from the cover also flows into the channel, formed in this way, a layer of water prevents knocking out of the coolant in the workshop through the connections of the cover with the chamber.

The operation of the camera is as follows:

After unloading, it is cleaned and checked. Operation of coolant supply valves is checked. After check chamber is loaded with articles, closed with cover, and coolant supply is switched on. The combustion products of the gas come from below the chamber where the air is located, rise up, mix with it and heat up to form a gas-air mixture. The total pressure of the chamber during all periods of heat treatment is equal to atmospheric, is composed of partial air pressure.

As the heat carrier arrives, the degree of heating of the material chambers increases and reaches the maximum temperature at the end of the period, since the partial pressure is always, even at the final heating moment, less than atmospheric.

Then the article is kept in the chamber at the reached temperature. With isometric heating, as soon as the temperature in the chamber reaches the maximum, the amount of gas supplied is reduced. After isothermal holding, cooling is started. For this purpose gas supply is cut off, cone is lifted and chamber ventilation channel is connected to ventilation system. The combustion products of the gas from the chamber, and from the surface of the material, together with the air, begin to be removed to the ventilation network, and the chamber cover begins to pass air from the workshop. Due to evaporation of moisture from channel, chamber increases or decreases extraction of gas-air mixture, rate of product cooling is changed.

The pit chamber operates in a cycle, it includes time for loading, for heating of products, for isothermal holding and cooling, as well as for unloading of material

In addition to the chamber itself, the plant for heat treatment of products with natural gas combustion products includes a heat generator, a recirculation, gas supply, ventilation and automatic control system.

The installation device with the TOB-2 heatgenerator

Heat generator TOB2 is used for heat treatment of reinforced concrete with natural gas combustion products in the pit chamber.

NagrevatelTOB-2 represents two concentric pipes. The outer pipe is part of the body, the inner pipe is heated by a burner with a ceramic tunnel installed in it and is equipped with ribs to increase the heat exchange surface with the recirculated heat carrier in the interval between the pipes and the heat carrier.

On the first approach of combustion products, the inner tube is finned only from the outside to improve its cooling, on the second, the ribs are passed through this tube to improve heat transfer from combustion products to the recirculated heat carrier. The recirculation fan removes heat carrier (air or mixture of product combustion and air) from the heat treatment chamber and directs it through the recirculation gas duct to the gap between the pipes.

Heated heat carrier is returned to heat treatment chamber through recirculation gas duct to increase temperature therein. The rate of temperature rise is controlled manually by changing the amount of gas entering the burner by means of a crane.

Vacuum in the furnace is provided due to ejection in the smoke distributor of combustion products by the recirculated coolant controlled by the gate

Ямная камера.dwg

Ямная камера.dwg