coupling alignment

Outline:  Introduction  Types of coupling and installation  Preparation of alignment  Tools and types of alignment  Alignment procedures

Introduction

Defining Shaft Misalignment: For two shafts to be called “aligned,” their shaft centerlines need to coincide If Together these centerlines do Not Form One line, then either parallel misalignment And/or angular misalignment Exists

What is coupling alignment?  Coupling alignment is shaft alignment. If the shafts are aligned, the couplings will normally go along for the ride.  Shaft alignment is the proper positioning of the shaft centerlines of the driver and driven components (i.e., pumps, gearboxes, etc.) that make up the machine drive train. Alignment is accomplished either through shimming and/or moving a machine component. Its objective is to obtain a common axis of rotation at operating equilibrium for two coupled shafts or a train of coupled shafts.

Why it is important to make shaft alignment?  up to 50% of damage to rotating equipment is directly caused by misalignment  Shafts must be aligned as perfectly as possible to maximize equipment reliability and life, particularly for high-speed equipment.  It is important because misalignment can introduce a high level of vibration, cause bearings to run hot, and result in the need for frequent repairs.  Proper alignment reduces power consumption and noise level, and helps to achieve the design life of bearings, seals, and couplings.

Why it is important to make shaft alignment? WITHOUT ALIGNMENTWITH ALIGNMENT

Misalignment Causes 1.Relative Movement – Thermal growth, or expansion, can cause one piece of equipment to move proportionately to another 2.Strain – Strain induced by attached piping runs can force equipment out of alignment. 3.Torsional Movement – The initial high torque caused during startup can force shafts out of alignment, causing torsional movement misalignment. 4.Settling – Over time, foundations or base-plates can settle to lower positions, causing settling misalignment. 5.Human Error – A mistake in an alignment procedure or not completing an alignment procedure can cause human error misalignment. 6.Misbored Couplings – Manufacturing defects, creating couplings that are misbored or otherwise distorted, can cause misbored coupling misalignment.

Effects 1.Excessive Vibration 2. Noise 3.Lost Production 4.Poor Quality of Products 5.Higher than Normal Repair Orders 6.Increased Inventory of Spare Parts 7.Reduced Profits

Types of Couplings: Shaft couplings are divided into two main groups. 1.Rigid coupling-: It is used to connect two shafts which are perfectly aligned. There are many types of couplings that fall under the rigid couplings category. They are: a.Sleeve or muff coupling b.Clamp or split-muff or compression coupling c.Flange coupling

Types of Couplings: 2.Flexible coupling: Flexible couplings are used to transmit torque from one shaft to another when the two shafts having both lateral and angular misalignment