Common sense of thermal pipeline flood control

1. What are the forms of heating pipeline laying?

Layout forms The plane layout of thermal pipelines mainly includes two types: dendritic and annular. 2。

Laying method (1) Overhead laying: The thermal pipeline is laid on the independent supports on the ground, trusses and walls of buildings. Overhead laying is not affected by groundwater level, which is convenient for maintenance and inspection.

It is suitable for areas with high groundwater level and geological unsuitability for underground laying, and it is a relatively economical laying form. Its disadvantages are large floor space and large heat loss of pipeline.

Overhead laying can be divided into three types according to the height of support: low support, medium support and high support. When laying low supports, the clear height of pipe insulation shell from the ground should not be less than 0.

3m； When the support is laid, the distance is generally 2. 0~4。

0m； When laying high support, it should not be less than 4. 5 million.

When the overhead pipeline is difficult or affects the beauty, the heat loss of the pipeline in cold areas is too large, or it is economically unreasonable to take insulation and anti-freezing measures, the underground laying method is adopted. (2) Trench laying Trench laying can be divided into three types: passable trench, semi-passable trench and impassable trench.

1) underground passage laying. When heating pipes pass through the road surface where excavation is not allowed, the number of heating pipes is large or the pipe diameter is large, and the vertical arrangement width of pipes on both sides of the trench exceeds 1.

5m, laid in trench. The clear height of the channel trench shall not be lower than 1.

8m, and the channel width should not be less than 0. 7 million.

2) Semi-traffic trench laying. When the ground through which the heating pipes pass is not allowed to be excavated, it is unreasonable to use overhead laying, or when the number of pipes is large and the width of the horizontal trench of a single row of impassable trench pipes is limited, semi-passable trench laying can be used.

The general clear height of the semi-traffic ditch is 1. 2~ 1。

4m, and the clear width of the channel is 0. 5~0。

6m, when the length exceeds 60m, there should be a channel. 3) Laying in impassable trench.

When the number of pipes is small, the pipe diameter is small, the distance is short, and the maintenance workload is not great, it is appropriate to use impassable trench for laying. Pipes in impassable trenches are usually laid horizontally in a single row.

When pipelines are laid in trenches, the clear distance between pipeline insulation shell and trench wall should be 200~ 150mm, between pipeline insulation shell and trench bottom should be 100~200mm, between pipeline insulation shell and trench top should be 50 ~ 100mm, and between pipeline insulation shell and trench top should be 200 ~ 300 mm

When valves, meters, drainage devices, decontamination devices and other accessories are installed at the branches of thermal pipelines in the trench, inspection wells or manholes should be set up. It is forbidden to lay flammable, explosive, volatile, toxic and corrosive liquid or gas pipelines in the thermal pipe trench.

If it is necessary to cross the pipe trench, protective casing shall be installed. (3) Directly buried.

2. How to maintain the heating pipes and valves?

Ball valves and globe valves are widely used in valves, with large usage and fast consumption. Therefore, when the heater comes in winter, reasonable maintenance can not only improve the work efficiency, but also reduce the maintenance time and save the replacement cost.

In order to make the ball valve and globe valve have stable performance and long service life, we need to pay attention to the following factors: first, before use, wash the overflow part of the pipeline and valve body with water to prevent residual iron filings and other impurities from entering the inner cavity of the valve body. Second: When the ball valve and globe valve are closed, some medium remains in the valve body, which also bears certain pressure.

Before overhauling the ball valve, close the cut-off valve in front of the ball valve, open the ball valve to be overhauled, and completely release the internal pressure of the valve body. If it is an electric or pneumatic ball valve, the power supply and air supply should be cut off first.

Fourthly, the sealing material of soft sealing ball valve is generally PTFE, and the sealing surface of hard sealing ball valve is metal surfacing. If it is necessary to clean the pipeline ball valve, pay attention to prevent the sealing ring from being damaged and leaking when disassembling.

It should also be noted that when disassembling the flanged pipe ball valve and globe valve, the bolts and nuts on the flange should be completely fixed first, then all the nuts should be slightly tightened, and finally fixed by force. If several nuts are forcibly fixed first, and then other nuts are fixed, the gasket surface will be damaged or cracked due to uneven lining between flange surfaces, resulting in leakage of valve flange docking medium.

Fifth: if the door cleans the valve, the solvent used must not conflict with the parts to be cleaned and will not corrode. If it is a special ball valve for gas, it can be cleaned with gasoline.

Other parts can generally be cleaned with reclaimed water. When cleaning, the residual dust, oil stain and other attachments must be thoroughly cleaned. If it cannot be cleaned with clean water, it can be cleaned with alcohol and other cleaning agents without damaging the valve body and parts.

After cleaning, the cleaning agent is completely volatilized before assembly. Sixth: If there is slight leakage at the packing during use, you can slightly tighten the stem nut until the leakage stops, and you can't continue to tighten it.

Seventh: Long-term open storage will lead to corrosion of valve body and parts, which can not be used normally. The ball valve should be waterproof, moisture-proof and waterproof, and the flange cover should be tightly covered.

Valves stored for more than 12 months should be re-tested in use to ensure stable performance. Eighth: Besides, it is very cold in winter. When selecting a valve, we should pay attention to the lowest temperature of the surrounding environment within the valve bearing range to prevent the valve from freezing and not working normally.

3. Safety requirements for thermal pipeline inspection

Catalogue of new technologies, new processes and new standards for manufacturing, installation, operation and maintenance and quality inspection of thermal pipeline engineering;

New technologies, new processes and standard specifications for manufacturing, installation, operation and maintenance and quality inspection of thermal pipeline engineering.

The first chapter is the introduction of the manufacturing and installation foundation of thermal pipeline engineering.

Chapter 1 Basic knowledge of thermal pipeline engineering

The second chapter is the hydrodynamics theory of thermal pipeline engineering and material heat treatment.

Chapter III Drawing Identification of Thermal Pipeline Engineering

Chapter IV Common Materials for Thermal Pipeline Engineering Construction

Chapter V Construction Machines and Tools Commonly Used in Thermal Pipeline Engineering Construction

Chapter VI Common Calculation of Thermal Pipeline Engineering Construction

The second article is about the new technology and process of pipe fitting manufacture and installation in thermal pipeline engineering.

Chapter I Processing and Manufacturing of Pipe Fittings

Chapter II New Technologies and New Processes for Manufacture and Installation of Common Valves in Thermal Pipeline Engineering

Chapter III New Technology and Process for Fabrication and Installation of Support in Thermal Pipeline Engineering

Chapter iv new connection technology and technology of thermal pipeline engineering.

Chapter V New Technologies and New Processes for Manufacture and Installation of Instruments and Instrument Pipes

Chapter VI Development of Thermal Pipeline Engineering Fittings: New Technology and New Process

Chapter VII New technologies and processes for manufacturing and installing thermal pipeline compensators

The third part is the new technology and new process of making, installing, operating and maintaining common materials in thermal pipeline engineering.

The first chapter is an overview.

Chapter II New technologies and processes for the manufacture, installation, operation and maintenance of polyethylene gas pipeline and steel skeleton plastic composite pipe.

Chapter III New Technologies and New Processes for Manufacture, Installation, Operation and Maintenance of Aluminum-plastic Composite Pipe

Chapter IV New technologies and processes for manufacturing, installation and operation of ABS pipes.

Chapter V New technologies and processes for the manufacture, installation, operation and maintenance of copper and copper alloy pipes

Chapter VI New technologies and processes for manufacturing, installation, operation and maintenance of carbon steel pipelines

Article 4 New technologies and processes for the production, installation, operation and maintenance of high, medium and low pressure thermal pipelines.

The first chapter is an overview.

Chapter II Pipeline Laying Mode

Chapter III New Technologies and New Processes for Manufacturing, Installation, Operation and Maintenance of Medium and Low Pressure Heat Pipelines

Chapter IV New Technologies and New Processes for Quality Inspection of High-pressure Thermal Pipelines

Fifth heating system equipment and new technologies and processes for production, installation, operation and maintenance.

Chapter I Performance, Manufacture and Installation of Heating Equipment

Chapter II New technologies and processes for the manufacture, installation, operation and maintenance of indoor steam heating systems

Chapter III Hydraulic Calculation of Steam Heating Pipe Network

Chapter IV Layout and Laying of Heating Pipelines

Article 6 New technologies and new processes for manufacturing, installation, operation and maintenance of industrial thermal pipelines.

Chapter I New technologies and processes for manufacturing, installation, operation and maintenance of compressed air pipelines

Chapter II New Technologies and New Processes for Manufacture, Installation, Operation and Maintenance of Oxygen Pipelines

Chapter III New Technologies and New Processes for Manufacture, Installation, Operation and Maintenance of Acetylene Pipelines

Chapter IV New Technologies and New Processes for Manufacture, Installation, Operation and Maintenance of Hydrogen Pipeline

Chapter V New technologies and processes for manufacturing, installation, operation and maintenance of high-purity dielectric pipelines

Article 7 New technologies and new processes for manufacturing, installation, operation and maintenance of gas-fired thermal pipeline projects.

Chapter I New technologies and new processes for the manufacture, installation, operation and maintenance of underground gas heating pipelines.

Chapter II New Technology and New Process for Installation of Auxiliary Equipment of Gas Heating Pipeline

Chapter III New technologies and processes for the manufacture, installation, operation and maintenance of above-ground gas heating pipelines

Chapter IV New technologies and new processes for the manufacture, installation, operation and maintenance of indoor gas heating pipelines

Chapter V New technologies and processes for the production, installation, operation and maintenance of outdoor gas pipelines.

Article 8 New technologies and new processes for thermal pipeline insulation, anti-corrosion construction and quality inspection.

Chapter I Thermal Insulation and Thermal Insulation Materials for Thermal Pipelines

Chapter II Thickness of Thermal Insulation Layer, New Technologies and Processes for Thermal Insulation Construction and Quality Inspection

Chapter III Anticorrosive Coatings

Chapter IV New Technologies and Processes for Surface Treatment

Chapter V New Technologies and Processes for Anti-corrosion Construction

Chapter VI New Technology and New Process of Heating Pipeline Coloring

Ninth thermal pipeline engineering quality inspection and common fault prevention, construction safety management and safety technology.

Chapter 1 Quality Hidden Dangers and Prevention of Thermal Pipeline Connection

Chapter II Quality Hidden Dangers and Prevention of Valves and Accessories

Chapter III Quality Inspection, Hidden Dangers and Prevention of Heating and Gas Pipelines

Chapter IV Quality Inspection, Pain and Prevention of Industrial Heating Pipelines

The fifth chapter pipeline anticorrosion, insulation quality inspection and pain prevention.

Chapter VI Acceptance, Startup, Operation and Maintenance of Heating System Production

Chapter VII Safety Management and Safety Technology of Heating Pipeline Manufacturing

Article 10 Relevant standards and specifications

4. What are the types of heating pipe networks?

(1) steam heating network 2 according to the type of heat medium. Hot water heating network II. Low temperature hot water heating network: t≤95℃.

(2) According to the location, 1. Primary pipe network: water supply and return pipe network from heat source to heating station; 2. Secondary pipe network: water supply and return pipe network from heating station to users. (3) According to the laying method of 1. Trench laying can be divided into: accessible trench, semi-accessible trench and impassable trench; 2. Overhead laying can be divided into high support, medium support and low support; 3. Directly buried laying: The pipeline is directly buried underground, and no trench is dug.

(4) Display the system form 1. Close system: The primary heating network and the secondary heating network are connected by heat exchangers. The heat medium loss of the primary heating network is very small, but there are many intermediate devices, which are widely used in practice; 2. Open system: direct consumption of primary heat medium, less intermediate equipment, but a large amount of primary heat medium supplement. (5) Classification by supply and return, 1. Water supply pipe (steam supply pipe in case of steam pipe network): the pipe from heat source to heat user (or thermal station); 2. return pipe (condensate pipe during steam pipe network): the pipe from heat users (or heating stations) back to the heat source.