Chapter 1 Installation of Ship Main Engine
Learning Objectives
Knowledge Objectives
1. Master the work content of host installation;
2. Learn the content and methods of base preparation;
3. Learn how to hoist the host;
4. Master the methods of positioning the host: positioning according to the flange of the shaft system; positioning according to the theoretical centerline of the shaft system;
5. Learn how to fix soil and machinery;
6. Master the installation method of large low-speed diesel engines.
Ability goals
1. Be able to prepare the base;
2. Be able to lift the host;
3. Will locate the host;
4. Can fix the host;
5. Capable of dismantling and assembling components of large low-speed diesel engines: base, main bearings and crankshaft, frame, cylinder block, piston device and cylinder head.
Section 1 Overview
The ship's main engine is the core of the ship's power plant. The quality of its installation will be directly related to the normal operation of the power plant and the navigation performance of the ship.
The main types of main engines include diesel engines, steam turbines and gas turbines. Different types of main engines have different structural characteristics and working methods. When installing on ships, corresponding process methods should be adopted according to different engine models. Diesel engine is currently the most widely used main engine. This chapter mainly discusses the installation process of diesel engine main engine.
The power generated by the main engine is transmitted to the propeller through the shaft system. The main engine is connected to the shaft system. The main engine, shaft system and propeller form an organic whole. Therefore, the installation of the main engine should be consistent with the installation of the shaft system. and consider. When building a ship, there are basically three installation sequences for the main engine and shafting: install the shafting first and then the main engine; install the main engine first and then the shafting; install the main engine and the shafting at the same time. The shaft system is first installed on the slipway, and after the ship is launched, the main engine is installed based on the shaft system. This is an installation process that has been used for a long time. Because this method can easily make the rotation center of the output shaft of the main engine coaxial with the rotation center of the shaft system, and at the same time avoid the influence of hull deformation after the ship is launched. The disadvantage of this method is that the production cycle is long. On the slipway, use the theoretical centerline of the shaft system as the benchmark to install the main engine and shaft system. You can install the main engine first, and then determine the position of the shaft system based on the actual position of the main engine and install the shaft system. The main engine and shaft system can also be installed at the same time. In this method, after the host is positioned, the piping system and various ancillary equipment can be installed, which expands the installation working surface and shortens the production cycle. However, this method is often difficult to avoid the impact of hull deformation after the ship is launched. When installing the shaft system, since the main engine and the tail shaft are already fixed, the deviation caused by the fixation of the two must be absorbed and constrained by the shaft system. Increase, installation is more difficult. In engineering practice, which installation sequence is adopted depends on the general shipbuilding process, the actual conditions of the factory, and the construction period.
After the main machine is installed, it is necessary to ensure that the relative position of the main machine and the shaft system is correct, and to maintain this relative position during operation. In order to prevent other factors from affecting the installation quality of the main engine, the following work must be completed before the main engine is installed:
(1) The main equipment and shafting system are basically transported and installed through the ship structure, superstructure and other major equipment in the area. Finish.
(2) The water testing of all compartments and double bottom tanks from the engine room to the stern of the ship should be completed.
The work content of the host installation can be summarized into the following aspects:
(1) Preparation of the host base (base).
(2) Positioning of the host (centering).
(3) Fixation of host.
(4) Quality inspection.
Section 2 Preparation of the main engine base (base)
The main engine is installed on the hull base through gaskets or shock absorbers, and the base is directly connected to the hull. Support base. Depending on the model, the base generally comes in two forms.
For large low-speed diesel engines, there is no separate tomb. The double bottom of the engine room is welded by thickened steel plates. The base of the main engine is located on this thickened steel plate, as shown in Figure 1-1. Small and medium-sized diesel engines usually have a protruding oil pan, so a metal component made of steel and steel plates needs to be welded on the double bottom, as shown in Figure 1-2. On the panel, a fixed gasket is welded to reduce the processing surface. There is a movable gasket between the fixed gasket and the diesel engine base to adjust the height of the main engine. The main engine and the base are fixed together with bolts. Chapter 2 Installation of Ship Shafting
Learning Objectives
Knowledge Objectives
1. Master the function and composition of the shaft system and the installation requirements of typical structures;
2. Master the technical conditions for the manufacturing and assembly of shaft system parts;
3. Master the main contents of the shafting installation process;
4. Learn the methods to determine the theoretical centerline of the shaft system: steel wire drawing method, optical instrument method;
5. Learn the boring of shafting holes: determination of processing round lines and inspection of round lines, technical requirements for boring, boring arrangement device, installation of boring arrangement machine on the ship, and boring process;
6. Learn how to install the stern tube device;
7. Master the meaning and method of shafting alignment: shafting alignment according to linearity, shafting alignment according to the allowable load on the bearings, and ship shafting alignment;
8. Learn how to install the shaft system: connecting the shaft system, tightening the intermediate bearing, and inspecting the installation quality.
Competence goals
1. Will determine the theoretical center line of the shaft system;
2. Able to boring shafting holes;
3. Can install stern tube device;
4. Ability to calibrate the axis system;
5. The shaft system can be installed correctly.
Section 1 Overview of the Ship Shaft System
1. The Function and Composition of the Shaft System
The function of the ship shaft system is to transmit the power generated by the main engine to the propeller ; The axial thrust generated by the rotation of the propeller is transmitted to the thrust bearing through the shaft system, and then transmitted to the hull from the thrust bearing to make the ship move forward or backward. Therefore, ship shafting is one of the important components of ship power plant. The quality of the shafting system will directly affect the normal navigation of the ship and is directly related to the operation of the main engine. Therefore, there are high technical requirements for the manufacturing and installation of shaft systems, and they must comply with relevant regulations of technical standards.
Ship shafting usually refers to the transmission device starting from the flange at the end of the main engine crankshaft (or the end of the reduction gearbox) and ending at the tail shaft (or propeller shaft). Its main components are: thrust shaft and its bearings, intermediate shaft and its bearings, tail shaft (or propeller shaft) and tail bearing, herringbone bearing, tail shaft tube and sealing device, and couplings of each shaft. Some ships also have short shafts to adjust the length of the shaft system. In addition, there are bulkhead stuffing boxes and band brakes.
There are many types of shaft system structures, including common propeller propulsion device shaft systems; adjustable pitch propeller propulsion device shaft systems; forward and reverse propeller propulsion device shaft systems; rotary propeller propulsion device shaft systems, etc. . They are very different from each other. However, as far as my country's civil ships are concerned, except for engineering ships and some small boats on inland rivers, most of them are commonly used propeller propulsion device shaft systems. Therefore, this book only introduces the manufacturing and installation process of commonly used propeller propulsion device shaft systems.
In civil ships, single or dual shaft systems are usually used, while passenger ships generally use dual shaft systems. The single shaft system is located on the midship longitudinal section of the ship, while the dual shaft systems are located on both sides of the ship and are symmetrical to each other. Dual-shaft ships have better maneuverability and relatively strong power plant vitality, and are mostly used in inland river ships. However, dual-shaft ships have complex structures, require a large amount of construction work, and are costly.
According to the requirements of the layout of the main engine and propeller, sometimes the axis and the baseline are at an inclination angle. Or form a deflection angle β with the longitudinal section. The tilt of the shaft system puts the main engine in poor working condition and reduces the effective thrust of the propeller.
In order to prevent the effective thrust of the propeller from significantly decreasing and to ensure the safety and reliability of the main engine, the α angle is generally limited to 0° to 5°, while the β angle is limited to 0° to 3°. For general speedboats, due to limited conditions, the α angle can reach 12° to 16°, but rarely exceeds 16°. For ships with a single shaft system, usually the shaft system is parallel to the vertical line (or keel line), that is. α=0°, but dual-shaft ships rarely meet the requirement of no inclination angle.
In the overall design of the ship, the engine room can be arranged in the middle or at the stern. When the nacelle is arranged in the middle, the shaft system is relatively long; when the nacelle is arranged at the tail, the shaft system is relatively short. - Generally speaking, a shaft system with two or more intermediate shafts. It is called a long shaft system. Some of the shaft systems of large ships in Zhongjixing are up to 100m in length, with as many as ten intermediate shafts; there is only one, and its length can be as short as 7 to 8 meters, or there is no intermediate shaft. called short axis system. The long shaft system has better flexibility and is easier to adjust, but it requires a lot of work to adjust and install. The rigidity of the short shaft system is relatively high, and the installation requirements are higher. For a dual-shaft ship, the rotation directions of the left and right main engines must be opposite. When the ship is moving forward, the starboard main engine will generally turn right, while the port main engine will turn left. If the rotation direction of the main engine is consistent, it can be achieved through a reversing mechanism. When one main engine drives two sets of left and right shaft systems, a reversing mechanism can also be installed to make the left and right shaft systems rotate in opposite directions.
When a thrust bearing is installed inside the main engine or reduction gearbox, the shaft system does not need to be equipped with an independent thrust bearing. The thrust shaft and its bearings have two functions: one is to bear the axial thrust generated by the propeller and transmit it to the hull, causing the ship to move; the other is to prevent the axial thrust generated by the propeller from directly pushing the crankshaft of the main engine and causing the crankshaft to move. and skew, causing damage to the main machine parts.
There are two common structural forms of thrust bearings. One is the horseshoe thrust bearing common on old ships; the other is a single-ring thrust bearing (also known as Michel thrust bearing). The former Has been eliminated.
The function of the bulkhead stuffing box is to keep the bulkhead watertight when the shaft system passes through the bulkhead to ensure the ship's sinking resistance. When the engine room is arranged aft, there is no need for a bulkhead stuffing box.
In ships with dual shaft systems, the shaft system is generally equipped with a braking mechanism. This is to use the braking mechanism to brake a certain power unit when it is necessary to stop it during navigation. Keep the shaft system from rotating due to the influence of water flow. In addition, the braking mechanism can also help the host shorten the reversing time.
The stern tube generally has two bearings at the front and rear. The front bearing is short and the rear bearing is longer. Some large ships have relatively short stern tubes, so only one stern tube bearing is installed. At this time, an intermediate bearing-type front bearing is often installed at the first end of the tail shaft to facilitate maintenance and management. Some ships also have longer stern tubes and are equipped with three stern tube bearings. Most of the tail tube bearings use sliding bearings. When the tail tube bearings are made of materials such as ironwood, rubber, laminate, and nylon, water is used as the cooling lubricant. At this time, the tail shaft is usually protected by a copper protective sleeve or a fiberglass protective layer to protect the tail shaft journal to prevent seawater from corroding the tail shaft. On older ships, outboard water is often used for natural cooling. This cooling method can easily cause "dead spots" with poor water flow, and often causes rapid wear of the shaft and bearings due to sediment entering the stern tube. Therefore, modern ships have adopted forced water lubrication and cooling to overcome the above shortcomings. Chapter 3 Assembly of Ship Shafting Components
Learning Objectives
Knowledge Objectives
1. Master the types of detachable couplings and their installation techniques;
2. Master the process method of shaft system matching;
3. Master the assembly method of stern tube assembly.
Competency goals
1. Can assemble detachable couplings;
2. Butt the flat shaft;
3. Will assemble the stern tube assembly.
Section 1 Assembly of Detachable Couplings
Detachable couplings are widely used in shaft systems where rolling bearings are installed, or in ships where the tail shaft must be installed from outside the hull. Festival.
There are many forms of detachable couplings for ship shafting, including flange detachable couplings, jacket couplings, hydraulic flange couplings and hydraulic detachable sleeve couplings.
1. Processing and assembly of flange-type detachable couplings
Flange-type detachable couplings are often used to connect the tail shaft and the intermediate shaft. It is It is a form of rigid coupling. According to the shape of the bolt holes on the connecting flange, it can be divided into two types: cylindrical bolt detachable coupling and conical bolt detachable coupling.
Figure 3-1 shows a cylindrical bolt detachable coupling. This kind of coupling has a flange edge, so it is called a flange-type detachable coupling.
1. Technical requirements for coupling processing
(1) The outer surface of the coupling and the flange end face should be rough machined first, leaving a margin of 3 to 5mm. , and the inner hole is processed in conjunction with the cone part of the shaft (the taper template can be used for measurement during processing). After the coupling and the cone part of the shaft are grinded and assembled, put the tail shaft on the lathe, and then add the outer circle of the coupling and the flange end face. The roughness and other technical requirements of the coupling are the same as those of the integral flange.
(2) The width, height and parallelism of the keyway on the coupling are the same as the processing requirements for the keyway on the shaft.
2. Assembly technical requirements for couplings
(1) The coupling taper hole and the shaft cone should be in good contact, and the contact area is required to be more than 75%. Check with colored oil. Within every 25mm×25mm, no Less than three points. When checking the big end of the cone with a thickness gauge, the insertion depth of the 0.03mm thickness gauge should not exceed 3mm. 1 to 2 small blank areas are allowed on the contact surface, but the total area should be less than 15% of the surface area of ??the cone, and the maximum length and width should not exceed 1/10 of the diameter of the cone at that location, and they must not be distributed in the same area. on the axis or circumference.
(2) The contact area between the flat key and both sides of the keyway on the shaft is not less than 75%. When matched with the coupling keyway, 85% of the length should not be inserted into a thickness of 0.05mm. The remaining parts should not fit into the 0.1mm thickness gauge. The flat key and the bottom of the keyway should be in contact; the contact surface should be no less than 30% to 40%.
(3) After the coupling flange bolts are installed, a 0.05mm thickness gauge should not be inserted into 90% of the circumference of the joint surface, and its contact area should not be less than 75%.
(4) The thread of the tapered part of the shaft should be retracted by a distance α into the tapered hole after the coupling is installed (Figure 3-1);
2. Processing and assembly of clamp-type coupling
The clamp-type coupling is composed of two steel semi-cylinders, and the torque is transmitted by the friction between the clamp and the shaft and the key. The cross-sectional size of the clamp coupling is relatively small, and the shaft does not need to be moved when disassembling, so it can be installed in narrow places that are difficult to enter. However, due to its heavy weight, its use is limited, as shown in Figure 3-2.
1. Processing technical requirements for couplings
(1) After processing the shell-shaped coupling, the roundness and cylindricity of the inner circle should meet the requirements of Table 3-1.
(2) When the length of the clamp shell exceeds twice the length of the journal, the taper error is allowed to increase by 0.01mm. The inner diameter should be 0.04~0.08mm larger than the journal. The distance between the two half couplings should be 3% to 5% of the journal.
(3) The inner circle surface roughness Rα is not greater than 3.2μm.
2. Assembly technical requirements for couplings
(1) The axial key must be repaired, and its assembly quality requirements are the same as the flat key requirements for flange-type detachable couplings.
(2) The thrust ring of the clamp coupling should be modified so that the inner circle closely matches the shaft groove, and the contact area is required to be above 60%. The matching parts of the shaft grooves or shell grooves on both sides should not be able to insert a 0.05mm thickness gauge.
(3) After assembly, a gap of 0.2 to 0.4mm is allowed between the outer circle of the thrust ring and the inner hole of the clamping case.
Chapter 4 Propeller Assembly and Installation
Learning Objectives
Knowledge Objectives
1. Learn how to process propellers;
2. Learn how to assemble propellers;
3. Learn how to install propellers.
Competency goals
1. Can process propellers;
2. Able to assemble propellers;
3. Propellers can be installed.
Section 1 Processing and Assembly of Propellers
1. Overview of Propellers
1. Basic concepts
The propeller is the most common ship propulsion device. It generally has 3 to 6 blades. Most propeller blades are cast together with the propeller shell, but some are also made detachable and bolted. The blades are fixed on the propeller shell and are called combined propellers. Small and medium-sized ships usually have 3 to 4 blades, and large ships usually have 4 to 5 blades. The function of the propeller is to convert the power generated by the ship's main engine into thrust to propel the movement of the ship. Its processing and assembly quality directly affects the navigation performance and safety of the ship. The correctness of propeller geometry is the main factor to ensure quality, among which propeller diameter and pitch are particularly important.
Figure 4-1 shows a three-blade propeller. The part connected to the tail shaft is called the propeller housing. Looking from the stern to the bow, the blade surface seen is called the pressure surface, which is a spiral surface, and its opposite surface is called the suction surface. The pressure surface is also called the blade surface, and the suction surface is also called the blade back; when the main engine rotates forward, the edge of the blade that enters the water first is called the leading edge, and the corresponding other side of the same blade is called the trailing edge.
The farthest point from the center of the propeller to the edge of the blade is the radius. The diameter of the circle is called the propeller diameter, represented by D. The distance that any point on the blade surface rises after one revolution around the propeller axis is called the propeller pitch H. Propellers can be divided into two types according to their pitch: constant pitch propellers and variable pitch propellers. The former has the same pitch on each radius section of its blade surface, but the latter does not. The pitch often increases with the increase of the radius within a certain radius range. Variable pitch propellers are more efficient, but manufacturing and processing the blades is more troublesome. There is also an adjustable-pitch propeller whose blades are flexibly mounted on the propeller casing, and the blades can be driven to rotate through an internal transmission mechanism to change the pitch to change the speed.
Looking from the tail to the head, when the car is turning, the propeller that rotates in the clockwise direction is called a right-hand propeller, and the propeller that rotates in the counterclockwise direction is called a left-hand propeller. For a sculled boat, a propeller that rotates outboard when heading forward is called an outboard propeller, and a propeller that rotates outboard when turning the other way is called an inboard propeller. Usually, a sculled boat uses outrotating propellers to prevent floating objects in the water from being drawn in and stuck. Since the propeller blades bear thrust, there must be a certain thickness between the blade surface and the blade back. There are two types of blade section shapes: machine-shaped and arcuate shapes, as shown in Figure 4-5 (flattened section shape). The distance b between the two endpoints is called the chord width, and the line connecting the two endpoints is called the chord line. The maximum thickness of the cut surface is represented by t. The t of the bow-shaped section is at the midpoint (b/2) of the chord width, and the t of the wing-shaped section is approximately 30 meters away. Chapter 5 Installation of Ship Auxiliary Engines and Boilers
Learning Objectives
Knowledge Objectives
1. Understand the general uses and types of auxiliary machines;
2. Understand the uses and types of deck machinery;
3. Understand the uses and types of boilers;
4. Describe the general installation process and precautions for ship auxiliary engines and boilers on ships.
Competency goals:
1. Will carry out the installation process of general auxiliary engines on the ship;
2. Be able to carry out the installation process of deck machinery on the ship;
3. Will carry out the installation process of the boiler on the ship;
4. Will blend and use commonly used adhesives.
Ship auxiliary machinery, namely ship auxiliary power machinery, is a complete set of power equipment that provides energy for the normal operation, operation, life and other needs of the ship.
Section 1: Installation of General Auxiliary Engines on Ships
There are many types of general auxiliary engines on ships. Common ones include marine pumps such as centrifugal pumps, screw pumps, jet pumps, etc. Air compressors, ventilators, ship refrigeration devices, ship air conditioning devices, oil separators, ship anti-fouling devices, seawater desalination devices, etc.; the quality of the installation of these auxiliary machines on the ship directly affects the normal operation of the ship.
1. The form in which ship auxiliary engines are transported to the ship for installation
Modern ship auxiliary engines are mainly transported to the ship in two forms for installation.
(1) Install the auxiliary engine combination into a unit. That is, the power part and the working part are installed on a rectangular base, such as the 3S100D screw pump (shown in Figure 5-1), or the power part is installed on a casing, such as the 3LU45 screw pump (Figure 5-2 shown); etc.
(2) Install the auxiliary engine combination into a functional unit. The DRY-5 oil separator shown in Figure 5-3 is an example. This form is more advanced than the former. When installing it on a ship, you only need to position it and tighten it, and then connect the pipeline and power supply to use it. It is very convenient. Some domestic shipyards have already used it, and the effect is very good.
The above two forms have the following better economic and technical effects than the installation of a single machine on the ship:
(1) Move most of the fitter assembly work from the ship to the workshop In this way, the equipment and favorable space conditions in the workshop can be fully utilized to improve the installation quality and labor productivity;
(2) Due to the supply of stereotyped products or pre-assembly, only the entire unit needs to be hoisted during shipbuilding. , which can greatly shorten the shipbuilding cycle; 3) Since the auxiliary engine itself has a public base or a casing, this reduces the processing requirements for the plane on the hull base combined with it, and the gaskets do not even need to be scraped Grinding greatly reduces the heavy fitter labor and facilitates the installation of shock absorbers (this is especially important for military products, because many auxiliary machines on ships are installed on shock absorbers).
2. Process items related to auxiliary machine installation
1. Preparation of the base
Auxiliary engines are generally installed on the base of the deck or hull through gaskets or shock absorbers. The deck support part does not need to be processed, and the processing requirements for the support surface of the base are not high. Generally speaking, the requirements for ships are slightly higher than those for civilian ships. The requirements for the base panel are as follows:
(1) The unevenness of the base panel shall not be greater than 3mm within a length of 1m, but shall not exceed 6mm in the full length or full width;
(2) The length and width tolerance of the base panel is 10~-5mm;
(3) When checking the diagonal line on the base panel, the two diagonals should intersect and their degree of non-intersection Should meet the following requirements: Length