Theprocess of reducing the misalignment of two adjacent shafts connected by a coupling so that the center of rotation for each shaft as near is. Shaft alignment methods explained bright hub engineering. Pipe strain, and its effect on shaft alignment empowering. Fixturlaser alignment tools display angular misalignment as a slope rise over run in mils1 the 0. Soft foot is a common issue when aligning rotating equipment. Piping stress considerations and practical remedies to overcome.
A static condition observed at the bearings supporting the propulsion shafts. Physical space limitations special bore or finish information and type of fit. A good static alignment is required for troublefree dynamic operation of the propulsion shafting. Api 686 chapter 4, piping alignment notes that the basic method of verifying pipe strain and its effect on the machinery is to monitor shaft alignment with dial indicators or lasers thru the machine flange torquing procedure. Rotate the shaft until the dial gauge reaches a maximum or a minimum reading. American petroleum institute code api rp 686 provides the data for acceptable deviation from the ideal perfect alignment. Api 686 only gives a recommended angular tolerance and nothing for offset alignment. S trade association for the oil and natural gas industry, representing about 400 corporations involved in production, refinement, distribution, and many other. Rough align rough align the machine vertically using a scale. Api standard 610, centrifugal pumps for general refinery services, american petroleum institute, washington, d.
Astm, iso, apipick an acronym, they all have specifications on. The api is an abbreviation for american petroleum institute. Laser alignment is an essential component of a viable. Table of contents a what is alignment b what is misalignment c types of misalignment d method of alignment e symptoms of misalignment f pre alignment checks g tools required for alignment h alignment tolerances. Acquip laser alignment training courses and seminars. A catalog of api publications and materials is published annually and updated quarterly by api, 1220 l street, n. Mauricio, the american petroleum institute api has shaft alignment standards api 610 that are used in the petrochemical industry, and i believe the hydraulic institute has developed shaft alignment standards as well. Our handson laser alignment course runs for two or three days. These changes in the shaft alignment can be accommodated in a few different ways. This document was produced under api standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an api standard.
Standards referenced by this book show below hide below api 618. Chapter 7 shaft alignment chapter 8 lubrication systems. Recommended practice for machinery installation and installation design march 2012 supplement to pip reie686 api rp686 process industry practices page 2 of 29 introduction purpose this practice supplements pip reie686 api rp686, recommended practice. Pdf process industry practices recommended practice for. Recommendations for checking rotating machinery installation. Api 686 practices shaft alignment free download as pdf file. The 10 steps outlined in this article reflect modifications. It is not intended as a comprehensive guide to alignment of process machinery, nor is it a substitute for seeking professional advice or reference to the manufacturers of the machinery. Only disc couplings and diaphragm couplings can be used in api 671 applications. Recommended practice for machinery installation and installation design march 2012 supplement to pip reie686 api rp686 process industry practices page 2 of 29 introduction purpose this practice supplements pip reie686 api rp686, recommended practice for machinery installation and installation design.
Api was formed in 1919 as a standardssetting organization and is the global leader in convening subject matter experts across segments to establish, maintain, and distribute consensus standards for the oil and gas industry. Metallic flexibleelement couplings are the primary type permitted for api 671 applications. Process measurement instrumentdescripcion completa. It is not intended as a comprehensive guide to alignment of process machinery, nor is it a substitute for seeking professional advice or. Shaft misalignment is responsible for as much as 50 percent of all costs related to rotating machinery breakdowns. Api recommended practice 686 machinery installation and installation designlast update. Alignment check methodology for rotary equipment using caesar. Machinery alignment tolerance tables the suggested alignment tolerances shown here are general values based upon experience and general industry standards and should not be exceeded. The courses covers from the fundamentals in laser alignment techniques, to performing a proper dynamic movement study thermal growth. Recommended practice for machinery installation and installation. Api 686 best practice for installation empowering pumps. Api 671 coupling standard coupling answers where the. With feeler gauge find obvious gaps and fill them with shims, taking care of any rough soft foot condition.
In its first 100 years, api has developed more than 700 standards to enhance operational safety, environmental protection. When shafts are aligned, the offset and the angular must be aligned. Care has been taken by the authors, pruftechnik ltd, in the preparation of this publication. Soft footwhat it is and how to minimize it vibralign. It is a major cause of repeatability problems in shaft alignment measurements.
If a manufacturer of a machine or coupling requires tighter alignment tolerances, those should be used. Api standard 610, centrifugal pumps for general refinery services. Applying one of the balancing quality grades such as iso 1940 and api 617. There are two types of misalignment, offset and angular see figure 2. Process industry practices recommended practice for machinery installation and installation design api recommended practice 686 second edition, december 2009. We provide shaft alignment api 686 compliance certification for your plant maintenance staff.
In addition to alignment quality and repeatability problems, it can be a cause of machinery vibration, reduce life in electric motors, and cause internal clearance problems in gearboxes and pumps. Hello members i would like to have clarification with regards to shaft alignment tolerances mentioned in api 686 second edition dec 2009 clause 5. Compressors, fans, blowers api std edition year published. Hello members i would like to have clarification with regards to shaft alignment tolerances mentioned in api 686 second edition dec 2009. Main engine shaft alignment comprehension check conditions. This recommended practice rp is intended to provide recommended procedures, practices, and checklists for the installation and precommissioning of new, existing, and reapplied machinery and to assist with the installation design of such machinery for petroleum, chemical, and gas industry services facilities. The laser method will not tell you how much the flanges have moved, but will tell you if that movement is sufficient to cause a change of shaft alignment between the machines. To take an example, a machine running at 6000 rpm with a 300mm spacer shaft installed would allow a maximum offset of. Take a normal set of shaft alignment measurements with the piping connected. In the past i have represented the end users or have done the construction myself. Api standards are available for purchase at the api publications store at. A similar process can also easily be done with laser shaft alignment tools. Alignment of the shaft is necessary when the motor or driven machinery is new or when it is dismantled due to improper running. With a loadonpad design, figure 1 the shaft is free to laterally within bearing clearance, and alignment data is difficult to obtain without temporary bearing shims to stabilize the sham with a loadbetweenpad design, figure 1 b, the shaft remains stable during the alignment procedure.
The goal and purpose of the pre alignment steps is to control unintended movement that might occur during the alignment process and maximize repeatability. Shaft centerline alignment is the positioning of the rotational centers of two. I cant see anything in api 610 or api 617 for pump or. Moreover, as the name suggests, the main purpose of shaft alignment is to make sure that the center line of the motor rotor shaft coincides with the center line of the driven machinery i. Chapter 6 provides guidelines for piping alignment as. Besides his work, alan enjoys spending time with his family and numismatics. A practical guide to shaft alignment plant services. The main purpose of shaft alignment is to make sure that the center line of the motor rotor shaft coincides with the center line of the driven machinery i. Once the step shimming task is complete and the alignment of the machines has been rechecked with all anchor bolts tight, do not neglect to trim off the excess part of the shims protruding out from under the edge of the machines foot to prevent possible injury. I would like to have clarification with regards to shaft alignment tolerances mentioned in api 686 second edition dec 2009 clause 5. Api standard 617, centrifugal pumps for general refinery services, american petroleum institute, washington, d. Steve chwyl, freelance mechanical specialist, planner, millwright disclaimer. Hp horsepower is the actual or transmitted power required by the application if unknown, use the motor or turbine. Api recommended practice 686 process industry practices.
Shaft alignment laser measuring resolution down to 0. How to do the alignment of shafts, compressors and. The purpose of this article is to give you a explanation about the pump configurations within the api 610. The aligning of two adjacent machinery shafts after the measurement of. Provisions of pip reie686api rp686 that are not revised remain in force. Nema sm23, steam turbines for mechanical drive service, national electrical manufacturers association, washington, d. Api 686 is written such that it can be used as a contractual document.
A summary of the guidance in regards to pipe strain is as follows. It can be resolved into a parallel offset at a given point along the fixed machine centerline and angular misalignment in both the horizontal and vertical planes. Aim to have all soft foot readings within 2 mils thou. However, i do want to share some knowledge and create conversation about this topic. The initial version of this procedure was published several years ago by me. Since then, a large amount of feedback has been accumulated. Recommended practice for machinery installation and. Save api rp 686 recommended practice for machinery installation for later. Changes in the temperature of machines from off line to running can have a significant impact on the shaft alignment. The course covers from the fundamentals in laser alignment techniques, to performing a proper dynamic movement study thermal growth. For spacer shafts, the table gives the maximum allowable offset for each 100 mm or inch of spacer shaft length. It is calculated, conducted and verified when the system is at rest.
Main engine shaft alignment comprehension check conditions items tolerance docking undocking bearing loads or reactions jackup curve understanding this content is password protected. Our handson laser alignment, vibration analysis and dynamic balancing of rotor courses run for two or three days. Shaft centerline alignment is the positioning of the rotational centers of two or more shafts such that they are colinear when the machines operate under normal conditions. I am not the absolute know everything about everything when it comes to the installation of process equipment. Experimental method which can be used for mass production. Shaft misalignment occurs when the center lines of coupled shafts do not. Api standard 617, centrifugal pumps for general refinery services, american petroleum institute. Shaft alignment chapter 8 lubrication systems chapter 9 commissioning. Explanation about the pump configurations within the api 610. Api rp 686 recommended practice for machinery installation. Alignment check methodology for rotary equipment using. Api 686 shaft alignment tolerances api american petroleum. As per the code if the vertical and horizontal deviation of piping flange and rotary equipment flange centerline is within 1.
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