Installation of Piping Systems
1.1 Installation of carbon steel pipes and pipe fittings
1) Installation of piping
Before installing the pipe, it is necessary to confirm the reference coordinates of the pipe installation. The basic installation method is to determine the installation position of the piping system according to the distance from the deck surface, rib position, center line surface or corresponding structure. In the installation process, the piping system should not be under stress. The flange connection surface should be perpendicular to the center line of the pipeline. The two adjacent flanges should be kept parallel to each other, and the centers of the two flange holes should be aligned as much as possible. The deviation is not greater than 3mm. The bolt holes on the two flanges should ensure that the screws can penetrate freely. In the installation process, the bolts must not be used to forcefully pull to eliminate the skew of the pipe.
2) Installation of sealing gaskets
The selection of sealing gaskets should be installed in strict accordance with the gasket material specified in the pipeline. The size of the sealing surface of the sealing gasket shall not be smaller than that of the sealing surface of the flange, and only one gasket can be placed between a pair of flanges. The gasket should be evenly stressed at the flange connection, and the inner diameter of the gasket should not be smaller than the inner diameter of the pipe, but not larger than the inner diameter of the flange sealing surface to avoid throttling or poor sealing caused by the gasket. During the installation of the paper gasket, you can apply butter on the surface of the gasket to soften the gasket and expand it in oil to achieve a better sealing effect.
3) Installation of fasteners
The selection and use of fasteners such as screws and nuts of the piping system should be strictly in accordance with the requirements of the drawings, and the correct materials and specifications should be selected. The same flange connection should use the bolts with the same specification, and the installation direction should be consistent. When the flange surface is parallel to the hull baseline, the hex head of the bolt is installed on the flange surface, and the nut is on the bottom. In the process of tightening the bolts, uniform and gradual tightening should be carried out according to the distribution of the screws and the principle of diagonal tightening. When the connecting flange finally reaches the corresponding tightening torque, the screw should be close to the flange without wedging, and 3 to 5 threads of the nut should be exposed for the tightened bolt.
4) Installation of pipe brackets
When installing the pipe support, the pipe should not be under stress, and the support should be installed on the strong support structure of the hull such as the hull longitudinal girder and hull frame, and the pipe support must not be directly welded to the hull plate. When the foot end of the bracket is on the deck or dry compartment, the bottom of the bracket should be welded to the backing plate; the welding between the backing plate and the hull is continuous full welding all around, and the welding between the bracket and the backing plate is to be continuously wrapped around the fillet welding. The direction of the back edge of the bracket angle steel is in principle towards the stern or outboard, and for vertical pipes, its direction should be downward.
When the pipe is installed, it should be fixed with a bracket or a hanger. The positions of brackets and hangers should be correct and the installation should be firm. Anti-corrosion materials such as green lead rubber and polyvinyl fluoride should be provided between the pipe and the supporting surface to avoid direct contact, but the contact between the pipe and the support should be sufficiently firm. When installing pipelines, use as few or no temporary supports and hangers as possible, and do not weld temporary supports and hangers. After the pipeline is installed, it should be replaced with a formal bracket and hanger in time.
5) Installation of piping parts
Before installing pipe parts, valves and filters, check their specifications and models according to the drawings. When installing the valve parts, the flow direction arrows on the valve parts are consistent with the flow direction of the medium in the pipe. For the installation of straight-through globe valves, globe check valves, anti-wave valves, and solenoid valves, the inlet and outlet of the valve body should be kept horizontal, and the valve parts should be kept horizontal. When the position of the wheel is under the flower iron plate, the valve handwheel should be upward.
When installing in narrow spaces, it is necessary to consider whether other hull structures and piping systems will affect the lifting of the handwheel. When the valve and the pipeline are connected by flanges or threads, the valve should be installed in the closed state; when the valve and the pipeline are connected by welding, the valve should be in the open state. The installation of the filter should consider the removal and washing of the filter screen in the later stage, and there should be no pipes above the filter.
1) Installation of piping
Before installing the pipe, it is necessary to confirm the reference coordinates of the pipe installation. The basic installation method is to determine the installation position of the piping system according to the distance from the deck surface, rib position, center line surface or corresponding structure. In the installation process, the piping system should not be under stress. The flange connection surface should be perpendicular to the center line of the pipeline. The two adjacent flanges should be kept parallel to each other, and the centers of the two flange holes should be aligned as much as possible. The deviation is not greater than 3mm. The bolt holes on the two flanges should ensure that the screws can penetrate freely. In the installation process, the bolts must not be used to forcefully pull to eliminate the skew of the pipe.
2) Installation of sealing gaskets
The selection of sealing gaskets should be installed in strict accordance with the gasket material specified in the pipeline. The size of the sealing surface of the sealing gasket shall not be smaller than that of the sealing surface of the flange, and only one gasket can be placed between a pair of flanges. The gasket should be evenly stressed at the flange connection, and the inner diameter of the gasket should not be smaller than the inner diameter of the pipe, but not larger than the inner diameter of the flange sealing surface to avoid throttling or poor sealing caused by the gasket. During the installation of the paper gasket, you can apply butter on the surface of the gasket to soften the gasket and expand it in oil to achieve a better sealing effect.
3) Installation of fasteners
The selection and use of fasteners such as screws and nuts of the piping system should be strictly in accordance with the requirements of the drawings, and the correct materials and specifications should be selected. The same flange connection should use the bolts with the same specification, and the installation direction should be consistent. When the flange surface is parallel to the hull baseline, the hex head of the bolt is installed on the flange surface, and the nut is on the bottom. In the process of tightening the bolts, uniform and gradual tightening should be carried out according to the distribution of the screws and the principle of diagonal tightening. When the connecting flange finally reaches the corresponding tightening torque, the screw should be close to the flange without wedging, and 3 to 5 threads of the nut should be exposed for the tightened bolt.
4) Installation of pipe brackets
When installing the pipe support, the pipe should not be under stress, and the support should be installed on the strong support structure of the hull such as the hull longitudinal girder and hull frame, and the pipe support must not be directly welded to the hull plate. When the foot end of the bracket is on the deck or dry compartment, the bottom of the bracket should be welded to the backing plate; the welding between the backing plate and the hull is continuous full welding all around, and the welding between the bracket and the backing plate is to be continuously wrapped around the fillet welding. The direction of the back edge of the bracket angle steel is in principle towards the stern or outboard, and for vertical pipes, its direction should be downward.
When the pipe is installed, it should be fixed with a bracket or a hanger. The positions of brackets and hangers should be correct and the installation should be firm. Anti-corrosion materials such as green lead rubber and polyvinyl fluoride should be provided between the pipe and the supporting surface to avoid direct contact, but the contact between the pipe and the support should be sufficiently firm. When installing pipelines, use as few or no temporary supports and hangers as possible, and do not weld temporary supports and hangers. After the pipeline is installed, it should be replaced with a formal bracket and hanger in time.
5) Installation of piping parts
Before installing pipe parts, valves and filters, check their specifications and models according to the drawings. When installing the valve parts, the flow direction arrows on the valve parts are consistent with the flow direction of the medium in the pipe. For the installation of straight-through globe valves, globe check valves, anti-wave valves, and solenoid valves, the inlet and outlet of the valve body should be kept horizontal, and the valve parts should be kept horizontal. When the position of the wheel is under the flower iron plate, the valve handwheel should be upward.
When installing in narrow spaces, it is necessary to consider whether other hull structures and piping systems will affect the lifting of the handwheel. When the valve and the pipeline are connected by flanges or threads, the valve should be installed in the closed state; when the valve and the pipeline are connected by welding, the valve should be in the open state. The installation of the filter should consider the removal and washing of the filter screen in the later stage, and there should be no pipes above the filter.
