Skip to main content

Pump Shaft Alignment Procedure - Horizontal

If the base plate has jackbolts installed, the task of moving the machine is made much easier. In many situations, it is best to have jack screws installed at the time of the alignment rather than trying to move the machine some other way, which is often more difficult and requires more time.
Before any of the hold-down bolts are loosened, all of the jackbolts must be loosened on the machine. Any unequal pressure of the jackbolts could result in an uncontrolled move and require the technician to take another set of alignment readings. When loosening the hold-down bolts, back them off just enough to allow the machine to slide sideways. Since it takes very little pressure on the jackbolt to move the machine horizontally, there is no real need to completely back off or remove the hold-down fasteners. If a graph is constructed determining the position of the misaligned shaft, you will know exactly which direction to move the machine. Another way to avoid confusion is to always look from the machine toward the machine.
  • Everything to the right, or toward the 3 clock position, is in the positive direction.
  • Everything to your left, or toward the 9 clock position, is in the negative direction.
This should help you visualize the proper direction for the move. The preferred and most accurate method for measuring the horizontal movement is to place dial indicators around the machine in the planes of the feet.
It is important that the indicators are positioned on the machine in the location used in the alignment calculation. This usually is the center of the hold-down bolt and at the approximate shaft height.

The procedure for performing a horizontal move of a machine is as follows:
  • Position the base-mounted dial indicators in the location of the machine's feet or at the point determined from the alignment calculation.
  • Adjust the dials to zero.
  • Move the machine in the proper direction by the determined amount, making sure all of the dial indicators agree.
Proper Dial Indicator Setup

No matter what device or method is used to move the machine, it is very important to have control of the machine. The most common problem encountered when moving the machine horizontally is that there are no jackbolts on the machine to maintain this control. If no jackbolts are installed, small hydraulic jacks can be used to move a machine if they are backed up to a solid structure, such as a beam, a solid wall, an adjoining pedestal, or a base. A chain fall or come-along can also be used. Again, they must be secured to something solid or immovable and operated one click at a time. Another very good idea is to use pony clamps or pipe clamps,  attached and operated to smoothly move the machine in the desired direction.
 


Labels:

Comments

Post a Comment

Popular posts from this blog

Difference Between A, B & C-Class Divisions?

IMO Symbol A Class Division  IMO Symbol B Class Division  SOLAS has tables for structural fire protection requirement of bulkheads and decks. The requirements depend on the spaces in question and are different for passenger ships and cargo ships. The Administration has required a test of a prototype bulkhead or deck in accordance with the Fire Test Procedures Code to ensure that it meets the above requirements for integrity and temperature rise. Types of Divisions: "A" Class "B" Class "C" Class "A" Class: "A" class divisions are those divisions formed by bulkheads and decks which comply with the following criteria: They are constructed of steel or equivalent material They are suitably stiffened They are constructed as to be capable of preventing the passage of smoke and flame to the end of the one-hour standard fire test. they are insulated with approved non-combustible materials such that the average tempera
14 comments
Read more

Bilge Injection Valve

Bilge Injection is a valve that enables the engine room bilges to be pumped out directly overboard in the event of an emergency such as flooding. The valve is normally fitted to the end of a branch connection with the main sea water suction line. This enables large main seawater cooling pumps to be used as a bilge pump in an emergency. Emergencies like fire and flooding involve the use of seawater. If there is a fire, seawater is the biggest resource of water available in the sea. Similarly, if it involves flooding of the engine room, cargo spaces or any other place on the ship for that matter; you would again require pumping the sea water out of the ship. In both these cases, you require pumps.  There are two valves in close proximity namely main injection valve and bilge injection valve. Both of them have their own independent controls. The diameter of the bilge injection valve is kept nearly 66% of the main valve diameter which draws water directly from the sea through the
Post a Comment
Read more

Load Line & Why it is Important

Merchant ships have a marking on their hull know as the Plimsoll line or the Plimsoll mark, which indicates the limit until which ships can be loaded with enough cargo, internationally, the Plimsoll line on a ship is officially referred to as the international load line. Every type of ship has a different level of floating and the Plimsoll line on a ship generally varies from one vessel to another.  All vessels of 24 meters and more are required to have this Load line marking at the centre position of the length of summer load water line. There are two types of Load line markings:- Standard Load Line marking – This is applicable to all types of vessels. Timber Load Line Markings – This is applicable to vessels carrying timber cargo. These marks shall be punched on the surface of the hull making it visible even if the ship side paint fades out. The marks shall again be painted with white or yellow colour on a dark background/black on a light background.  The comp
15 comments
Read more