WELDING PERFORMANCE QUALIFICATION TEST (WPQ)

A Welder Performance Qualification (WPQ) is a test certificate that shows whether a welder possesses the necessary experience and knowledge to perform the specifications of a particular weld procedure.

The scope of the WPQ test varies depending on the weld procedure, but it generally involves non-destructive and destructive testing. To completed this procedure, the need of staff required includes chemists, engineers and NDT inspectors. The on-site, full-service machine shop can prepare any size weld coupon for testing. After passing required tests, they will issue you a qualification certificate.

Some of the Welder Performance Qualification (WPQ) / Welding Qualification Test Reord (WQTR) form after completed welding test is shown below:

Steel - Storage and Handling

Hello..

Generally, greater care is required in storing and handling stainless steel than carbon steel to avoid damaging the surface finish (especially for bright annealed or polished finishes) and to avoid contamination by carbon steel and iron.

Storage and handling procedures should be agreed between the relevant parties to the contract in advance of any fabrication and in sufficient detail to accommodate any special requirements. The procedures should cover, for instance, the following items:

• The steel should be inspected immediately after delivery for any surface damage.
• The steel may have a protective plastic or other coating. This should be left on as long as possible, removing it just before final fabrication. The protective covering should be called for in the procurement document if it is required (e.g. for bright annealed finishes).
• Storage in salt-laden humid atmospheres should be avoided. Storage racks should not have carbon steel rubbing surfaces and should, therefore, be protected by wooden, rubber or plastic battens or sheaths. Sheets and plates should preferably be stacked vertically; horizontally stacked sheets may get walked on with a risk of iron contamination and surface damage.
• Carbon steel lifting tackle, e.g. chains, hooks, and cleats should be avoided. Again, the use of isolating materials, or the use of suction cups, will prevent iron pick-up. The forks of fork lift trucks should also be protected.
• Contact with chemicals including undue amounts of oils and greases (which may stain some finishes) should be avoided.
• Ideally, segregated fabrication areas for carbon steel and stainless steel should be used. Only tools dedicated to stainless steel should be employed (this particularly applies to grinding wheels and wire brushes). Note that wire brushes and wire wool should be of stainless steel and generally in a grade that is equivalent in terms of corrosion resistance (e.g. do not use ferritic stainless steel brushes on austenitic stainless steel).
• As a precaution during fabrication and erection, it is advisable to ensure that any sharp burrs formed during shearing operations are removed.
• Consideration should be given to any requirements needed in protecting the finished fabrication during transportation.

Thats all for today..see u next articles.

How To Calculate Shear Forces On Bolts Connection Joints

How to determine shear forces on bolts?

Here's below shows one of the simple shear forces calculation of bolts connection joints when received Mxx = 46.223 kN/M of maximum bending moment.

Mxx =     M dead  +  M live   
        =   16.147  +  30.076
        =     46.223 kN/M

Flexible Pavement Design

Flexible Pavement Design

Design Procedure of IRC

Design Approach and Criteria - The following three types of pavement distress resulting from repeated application of traffic are considered:

(i) Horizontal tensile strain at the bottom of the bituminous layer
(ii) Vertical compressive strain at the top of the subgrade
(iii) Pavement deformation with in the bituminous layer

The deformation with in the bituminous layer is assumed to be controlled by meeting the mix design requirements

Failure Criteria

1. Fatigue Cracking

• Is due to the build up of tensile strain at the bottom of Asphaltic Concrete Layer
• Pavement is considered failed if 20% of the surface has cracked

2. Rutting Failure

• Is due to the build up of excessive compressive strain at the top of subgrade layer
• Pavement is considered failed if it exhibits a rut depth of 20 mm.

IRC Design Approach and Criteria

The pavement has been modeled as a three layer structure and stresses and strains at

critical locations have been computed using the linear elastic structural model FPAVE.

Nondestructive Testing with Bruker Handheld XRF Analyzers

Non-destructive testing or NDT – also called non destructive examination (NDE), nondestructive inspection (NDI), and non-destructive evaluation (NDE)  – with Bruker handheld XRF analyzers can be achieved in seconds or minutes for a broad variety of applications.  By contrast, other elemental analysis techniques, such as OES (Optical Emission Spectrometry) leave a spark mark on the alloys being analyzed; and ICP (Inductively Coupled Plasma) analysis or AA (Atomic Absorption) analysis are destructive to the sample.  Handheld XRF allows you to perform completely nondestructive testing on practically any material.

When it is crucial that materials not be marred in any way yet elemental analysis is required, nondestructive testing with handheld XRF guns make it possible for many manufacturers, retailers, distributors and consultants to remain compliant with regulations:

• Art Conservation and Restoration
• Consumer Products/H.R.4040 with the (S1 TITAN) XRF Gun
• Lead in Apparel with the S1 TITAN
• TPCH- Toxics in Packaging Clearing House Laws
• ASTM F-963 - The Mandatory Toy Standard
• RoHS- Restriction of Hazardous Substances
• Prop 65- Lead restricted from all products sold in CA
• Jewelry Evaluation - Precious Metals, Gold, Silver
• PMI Analysis
• Positive Materials Identification in Aerospace Alloys
• QA/QC for Alloys

There are also applications in industries where nondestructive testing is not required yet it makes life a lot easier if the sample is not destroyed and can be confirmed with back up analysis in a laboratory:

• Soil Remediation
• Mining Exploration

Whether you are striving to comply with regulations or conducting elemental analysis where nondestructive testing is necessary for optimum efficiency, handheld XRF analyzers from Bruker can get the job done, quickly, effectively and nondestructively.

Analysis and Design of the Fastener

Analysis and retrofitting design of the fastener group for the spreader                 

                                         bar of SM3 disassembly 

Background:

      Try to re-use (or to modify) the existing Mino project spreader bar for SM3

      disassembly project. the capacity of the spreader bar for SM3 project is:

               Overall load P_t = 9.4 tons with span distance L_s = 201 in

               

Applicable codes:

      ASME B30.20; “Below – the – Hook Lifting Devices”

      ASD, AISC 9^th edition

     

References:

      ME – 397459

      ME – 397426

      MD – 397452

      “Steel Structures Design and Behavior” by C. Salmon & J. Johnson, 3^rd edition

Assumptions:

      Slip critical  connection, single shear

     

Figure 1 of  page 1 is showing that when the applying load P is eccentric to the centroid of the bolt group, this physical configuration is the actual design of the spread bar using for sm3 project.

  

                

Where:

       P = 9,400 lbs, applying load

       L = 47.625 in

       Location A is the geometrical centroid of the bolt group, 6  bolts are located as

       showing in Figure 1. currently, it is assuming: A325, ¾ - 10, UNC

       n = 6

       per Table I –D, part 4 of ASD,  R_av = 7.51 kip (allowable shear load)

Find out the local properties of the fastener group:

      ∑x² =  4 (4)² = 64 in²

         ∑y²  = 6 (2)² = 24 in²

      ∑x² +  ∑y²    = 88 in²

The primary shear load R_v of each bolt subject to the applying load P:

     R_v = P/n = 9,400 lbs / 6

          = 1,567 lbs ↓

The secondary torsional shear load of the bolt subject to the moment PL:

   To pick the bolt of the most right top one as showing in figure 1,

Where: R_x = PLy ÷ (∑x² +  ∑y²)

                  = (9,400 lbs) x (47.625 in) x (2 in) ÷ 88 in²

                  = 10,174 lbs. →

             R_y =  PLx ÷ (∑x² +  ∑y²)

                  =  (9,400 lbs) x (47.625 in) x (4 in) ÷ 88 in²

                  =  20,349 lbs ↓

The resultant force applying to the most right top bolt:

             R = [(R_v + R_y)² + R_x² ]^1/2            

                 = [(1,567 + 20,349)² + (10,174)² ]^1/2  lbs

                 = 23,259 lbs > R_av = 7.51 kip

It is necessary to look for:

      a. Different specifications of the fastener with the same fastener group.      

      b. Another pattern of the fastener group

A.Different specification of the fastener with the same fastener group:

     A1. If using 6 bolts with A325, 1 3/8”- 6 UNC,*   

       then R_av = 25.2 ksi > R = 23.26 ksi,

 *:  The hole ctr. to hole ctr. distance L_e = 4.0 in < 3d = 4.13 in

    A2. If using same fastener group with bolt of A490, 1 ¼”- 7, UNC,

 then R_av = 25.8 ksi > R = 23.26 ksi (per Table I-D, part 4 of ASD, 9^th edition)

 where: L_e = 4.0 in > 3d = 3.75 in

B. Modify the current pattern of the fastener group:

    Figure 2 on page 3 is the new fastener group with adding additional 10 fasteners to

           the original group, it can be found the new properties of the fastener group:

      ∑x² =  (4 (4)² + 4 (2)² + 6 (6)²) in²

                   = (64 + 16 + 216) in²

             = 296 in²

      ∑y²  = (6(2)² + 8(3.375)²) in²

                    = 115 in²          

                             

          ∑x² +  ∑y²    = (296 + 115) in²

                                   = 411 in²

              Also n = 16

The primary shear load R_v of each bolt subject to the applying load P:

     R_v = P/n = 9,400 lbs / 16

          = 588 lbs ↓

The secondary torsional shear load of the bolt subject to the moment PL,

To pick the bolt of the most right top one as denoted as bolt A of Figure 2:

Where: R_x = PLy ÷ (∑x² +  ∑y²)

                  = (9,400 lbs) x (47.625 in) x (3.375 in) ÷ 411 in²

                  = 3,677 lbs. →

             R_y =  PLx ÷ (∑x² +  ∑y²)

                  =  (9,400 lbs) x (47.625 in) x (6 in) ÷ 411 in²

                  =  6,536 lbs ↓

The resultant force R applying to the most right top bolt A:

             R = [(R_v + R_y)² + R_x² ]^1/2            

                 = [(588 + 6,536)² + (3,677)² ]^1/2  lbs

                 = 8,017 lbs > R_av = 7.51 kip

If the bolt material change to ASTM A490, then  R_av = 9.28 kip

             R = 8.017 kip < R_av = 9.28 kip

Since only 2 bolts of the fastener group will experience shear load of R ~ 8.017 kip, all the rest bolt shear load is less than 7.51 kip, so there are two choices:

1.      The most top right and bottom right bolts use A490, the rest bolts use A325. (3/4 – 10,  UNC.)

2.      Or all of them use A490 bolts (3/4 – 10, UNC)

The conclusions:

There are two ways to modify the current fastener group to meet the new design criteria of spreader bar for SM3 disassembly:

1.      Using (6) A490 high strength structural bolts with spec. of 1¼ - 7, UNC (original is ¾ -10, UNC), or

2.      Using (16) A490 high strength structural bolts with spec. of ¾ -10, UNC.

Determine the Operating Group of the Hoist

General Comparison

Summarizing

To select correct crane duty, crane structure and mechanical components, the user must identify and pass on the following information to the supplier:

1. Average lifts and trolley and bridge movements made in an hour.
2. Average length of each movement.
3. Estimate the load lifted each time.
4. Total operating hour per day.

FEM SERVICE CLASS

To determine your crane duty group (according to FEM, Fédération Européene de la Manutention) you need following factors:

1) Load spectrum (Indicates the frequency of maximum and smaller loadings during examined time
period).

2) Class of utilization (This is determined according to number of hoisting cycles during lifetime of crane)

3) Combining these factors is how a duty group is selected.

Example of different load spectrums:

Calculate the Average Daily Operating Time

t = (2 x H x N x T) / (V x 60)

Where:

 H = average hoisting height (m or feet)
 N = number of work cycles per hour (cycle/hour)
 T = daily working time (h)
 V = hoisting speed (m/min or feet/min)

AISE SERVICE CLASS

AISE also provides for different service classes for cranes covered under AISE Technical Report No. 6, "Specifications for Electric Overhead Traveling Cranes for Steel Mill Service". Like CMAA, AISE also provides a numerical method for determining crane class based on the expected load spectrum. Without getting into the specifics of this method, AISE does generally describe the different service classes (load cycles) as follows:

1. Service Class 1 (N1): Less than 100,000 cycles

2. Service Class 2 (N2): 100,000 to 500,000 cycles

3. Service Class 3 (N3): 500,000 to 2,000,000 cycles

4. Service Class 4 (N4): Over 2,000,000 cycles

Further AISE describe the different Load Classes as

1. L1= Cranes which hoist the rated load exceptionally, and normally hoist very light loads

2. L2= Cranes which rarely hoist the rated load, and normally hoist loads about 1/3 the rated capacity

3. L3= Cranes which hoist the rated load fairly frequently, and normally hoist loads between 1/2 and 2/3 or the rated capacity

4. L4= Cranes which are regularly loaded close to the rated capacity

Based on the load classes and load cycles, the CMMA chart below helps determine the class of the crane.

HMI/ASME HOIST DUTY RATINGS

The following table provides an idea of the relative significance of the duty cycle ratings for the various electric hoists. Note that the duty cycle determination for a particular application involves obtaining a significant amount of additional information and expertly applying it to the intended use.

CLASSIFICATION OF CRANES

Crane Duty Groups

Crane duty groups are set of classifications for defining the use of crane. There are several different
standards where these groups are named differently. One may have heard names CMAA, FEM, ISO or HMI. They all have their own classification of duty groups but are still based on the same calculations and facts. Following is a short description of what a duty group means and what it is for.

A crane duty group tells which kind of duty the crane is for; the range is from light duty up to very heavy duty. It is vital to define the needs and estimate the use because of safety reasons and for to ensure a long working life for the crane. You can't put for example a crane designed for light duty into continuous heavy-duty work.

CMAA Crane Classification

As to the types of cranes covered under CMAA Specification No. 70 (Top Running Bridge and Gantry Type Multiple Girder Electric Overhead Traveling Cranes); there are six (6) different classifications of cranes, each dependent on duty cycle. Within the CMAA Specification is a numerical method for determining exact crane class based on the expected load spectrum. Aside from this method, the different crane classifications, as generally described by CMAA, are as follows:

ESSENTIAL PARAMETERS FOR SPECIFING EOT CRANES - Part 2

Hello Structural Engineering readers, how are u? Today we continued some more tips about the above topic for your further explanation.

Other than addressing the last post (see here) parameters, some specific conditions applicable to your application must be mentioned.

1) Do you need the use of a second hoist on the bridge crane? (This hoist may be used as an auxiliary hoist or be required in a process such as tilting/tipping. In case you are handling long materials, like steel tubes and plates, the best solution are to have a crane with two hoists (and hooks) for better stability of the load ensuring safe lifting).

2) What will the operating environment be (dust, paint fumes, outdoor, etc.)?

3) Is there existing cranes on the runway? Then, consider the use of a collision avoidance or collision warning system.

4) Do you require a catwalk on the crane for maintenance access?

5) What other accessories are required such as lights, warning horns, weigh scales, limit switches, etc.

Load is defined as the maximum working load suspended under the load hook. Load block and ropes are not included in the rated load.

The design load for the crane system is based on the rated capacity plus 15% for the weight of the hoist and trolley (capacity x 1.15) and an additional 25% for impact (capacity x 1.25) for a total design capacity x 1.4. (Note 25% impact factor is good for hoists speeds up to 50 fpm).

The capacity of crane is the maximum rated load (in tons) which a crane is designed to carry. The net
load includes the weight of possible load attachment. For example , a 1000 lb crane allow you to pick up a 1000lb load, provided the hoist weighs 150lbs or less and the hoist speed is less than 50 feet per minute.

Under no conditions should the crane be loaded beyond its rated capacity.

Note that the Crane test loads are typically specified at 125% of rated capacity by both OSHA and ASME.

ESSENTIAL PARAMETERS FOR SPECIFING EOT CRANES

Hii readers, today we will show you some tips how to select correct crane envelope that will fit in the building foot print, and the user must identify and pass on the following key information to the supplier before proceed with manufacturing process:

1) Crane Capacity  - The rated load, the crane will be required to lift. Rated load shall mean the
maximum load for which a crane or individual hoist is designed and built by the manufacturer and
shown on the equipment identification plate.

2) Lift Height - The rated lift means the distance between the upper and lower elevations of travel of
the load block and arithmetically it is usually the distance between the beam and the floor, minus the
height of the hoist. This dimension is critical in most applications as it determines the height of the
runway from the floor and is dependent on the clear inside height of the building. Do not forget to
include any slings or below the hook devices that would influence this value.

3) Runway Height – The distance between the grade level and the top of the rail.

4) Clearance - The vertical distance between the grade level and the bottom of the crane girder.

5) Clear Span- Distance between columns across the width of the building. Building width is defined as the distance from outside of eave strut of one sidewall to outside of eave strut of the opposite
sidewall. Crane Span is the horizontal center distance between the rails of the runway on which the
crane is to travel. Typically distance is approximate to 500mm less than the width of the building.
How much span a crane requires depends on the crane coverage width dictated by the application.
(According to the span and the maximum load handling capacity, the crane steel structure is
selected to be either a single or double girder crane construction).

6) Building Height - Building height is the eave height which usually is the distance from the bottom of the main frame column base plate to the top outer point of the eave strut. Eave height is the
distance from the finished floor to the top outer point of the eave strut. There must be a safety
distance between the top edge of the crane runway rail and the first obstacle edge in the building
(for example roof beams, lights and pipes).

7) Runway Length- The longitudinal run of the runway rail parallel to the length of the building.

8) Hook approaches - Maximum hook approach is the distance from the wall to the nearest possible
position of the hook. The smaller the distance is, the better can the floor area be utilized. Always
check which crane gives optimum hook approaches and when combined with the true lift of the hoist
you can utilize most of the available floor space. This is also termed as side hook approach.
End Approach – This term describes the minimum horizontal distance, parallel to the runway,
between the outermost extremities of the crane and the centerline of the hook.

9) Bridge, Trolley and Lift Speeds - The rate at which the bridge or trolley travels or at which the hoist lifts is usually specified in feet per minute or FPM. The crane operating speeds are selected to allow safe operation whilst using the pendant. Dual operating speeds, normally a fast and slow speed with a ratio of 4:1 are commonly used but for optimum control a variable speed control system is strongly recommended.

10) Electrical Requirements - Specify the circuit voltage shall not exceed 600 volts for AC or DC current. Ideally 480 volt, 3 phase, 60 hertz for US requirements. The runway power is usually by conductor bar and hoisting trolley by festoon cable. (refer section 6 for details)

11) Control Requirements - The control circuit voltage at pendant pushbuttons shall not exceed 150
volts for AC and 300 volts for DC. Other control options including radio control, free-floating pendant (festooned) or hoist-mounted pendant requirements must be stated.

Ok, thats all for today. We will learn some more in next post. Thank you for reading.

SPECIFYING AN OVERHEAD CRANE

Specifying an overhead crane. This is generally structural layout where overhead crane is located in building.

BASIC CRANE COMPONENTS

To help you and the reader better understand names and expressions used throughout this course, find below is a diagram of basic crane components.

1) Bridge - The main traveling structure of the crane which spans the width of the bay and travels in a direction parallel to the runway. The bridge consists of two end trucks and one or two bridge girders depending on the equipment type. The bridge also supports the trolley and hoisting mechanism for up and down lifting of load.

2) End trucks - Located on either side of the bridge, the end trucks house the wheels on which the entire crane travels. It is an assembly consisting of structural members, wheels, bearings, axles, etc., which supports the bridge girder(s) or the trolley cross member(s).

3) Bridge Girder(s) - The principal horizontal beam of the crane bridge which supports the trolley and is supported by the end trucks.

4) Runway - The rails, beams, brackets and framework on which the crane operates.

5) Runway Rail - The rail supported by the runway beams on which the crane travels.

6) Hoist - The hoist mechanism is a unit consisting of a motor drive, coupling, brakes, gearing, drum, ropes, and load block designed to raise, hold and lower the maximum rated load. Hoist mechanism is mounted to the trolley.

7) Trolley - The unit carrying the hoisting mechanism which travels on the bridge rails in a direction at right angles to the crane runway. Trolley frame is the basic structure of the trolley on which are mounted the hoisting and traversing mechanisms.

8) Bumper (Buffer) - An energy absorbing device for reducing impact when a moving crane or trolley reaches the end of its permitted travel, or when two moving cranes or trolleys come into contact. This device may be attached to the bridge, trolley or runway stop.

EOT CRANE CONFIGURATION

Today's post is to know electric overhead travelling crane configuration.

1) Under Running (U/R)
2) Top Running (T/R)

Under running cranes

Under Running or under slung cranes are distinguished by the fact that they are supported from the roof structure and run on the bottom flange of runway girders. Under running cranes are typically available in standard capacities up to 10 tons (special configurations up to 25 tons and over 90 ft spans). Under hung cranes offer excellent side approaches, close headroom and can be supported on runways hung from existing building members if adequate.

The Under Running Crane offers the following advantages:

o Very small trolley approach dimensions meaning maximum utilization of the building's width and height.
o The possibility of using the existing ceiling girder for securing the crane track.

Following are some limitations to Under Running Cranes:-

o Hook Height - Due to Location of the runway beams, Hook Height is reduced
o Roof Load - The load being applied to the roof is greater than that of a top running crane
o Lower Flange Loading of runway beams require careful sizing otherwise, you can "peel" the flanges off the beam

Top Running Cranes

The crane bridge travels on top of rails mounted on a runway beam supported by either the building columns or columns specifically engineered for the crane. Top Running Cranes are the most common form of crane design where the crane loads are transmitted to the building columns or free standing structure. These cranes have an advantage of minimum headroom / maximum height of lift.

Which Crane should you choose – Single Girder or Double Girder?

Hii..this post is about which crane should you choose either Single Girder or Double Girder?

A common misconception is that double girder cranes are more durable! Per the industry standards (CMMA/DIN/FEM), both single and double girder cranes are equally rigid, strong and durable. This is because single girder cranes use much stronger girders than double girder cranes. The difference between single and double girder cranes is the effective lifting height.

Generally, double girder cranes provide better lifting height. Single girder cranes cost less in many ways, only one cross girder is required, trolley is simpler, installation is quicker and runway beams cost less due to the lighter crane dead weight. The building costs are also lower. However, not every crane can be a single girder crane. Generally, if the crane is more than 15 ton or the span is more than 30m, a double girder crane is a better solution.

The advantages and limitations of Single / double girder cranes are as follows:

Single Girder Cranes

o Single girder bridge cranes generally have a maximum span between 20 and 50 feet with a
maximum lift of 15-50 feet.
o They can handle 1-15 tonnes with bridge speeds approaching a maximum of 200 feet per minute (fpm), trolley speeds of approximately 100 fpm, and hoist speeds ranging from 10-60 fpm.
o They are candidates for light to moderate service and are cost effective for use as a standby (infrequently used) crane.
o Single girder cranes reduce the total crane cost on crane components, runway structure and building.

Double Girder Cranes

o Double girder cranes are faster, with maximum bridge speeds, trolley speeds and hoist speeds approaching 350 fpm, 150 fpm, and 60 fpm, respectively.
o They are useful cranes for a variety of usage levels ranging from infrequent, intermittent use to continuous severe service. They can lift up to 100 tons.
o These can be utilized at any capacity where extremely high hook lift is required because the hook can be pulled up between the girders.
o They are also highly suitable where the crane needs to be fitted with walkways, crane lights, cabs, magnet cable reels or other special equipment.

TYPES OF ELECTRIC OVERHEAD CRANES - Part 2

Hii...we continued the last post that talk about overhead crane generally or basically..

There are various types of overhead cranes with many being highly specialized, but the great majority of installations fall into one of three categories:

a) Top running single girder bridge cranes,
b) Top running double girder bridge cranes and
c) Under-running single girder bridge cranes.

Electric Overhead Traveling (EOT) Cranes come in various types:

1) Single girder cranes - The crane consists of a single bridge girder supported on two end trucks. It has a trolley hoist mechanism that runs on the bottom flange of the bridge girder.

2) Double Girder Bridge Cranes - The crane consists of two bridge girders supported on two end trucks. The trolley runs on rails on the top of the bridge girders.

3) Gantry Cranes - These cranes are essentially the same as the regular overhead cranes except that the bridge for carrying the trolley or trolleys is rigidly supported on two or more legs running on fixed rails or other runway. These “legs” eliminate the supporting runway and column system and connect to end trucks which run on a rail either embedded in, or laid on top of, the floor.

4) Monorail - For some applications such as production assembly line or service line, only a trolley hoist is required. The hoisting mechanism is similar to a single girder crane with a difference that the crane doesn’t have a movable bridge and the hoistingtrolley runs on a fixed girder. Monorail beams are usually I-beams (tapered beam flanges).

Ortie, see u next post..thanks.

General Overview - Overhead Crane Part 1

Cranes are industrial machines that are mainly used for materials movements in construction sites, production halls, assembly lines, storage areas, power stations and similar places. Their design features vary widely according to their major operational specifications such as: type of motion of the crane structure, weight and type of the load, location of the crane, geometric features, operating regimes and environmental conditions.

When selecting an electric overhead traveling crane, there are a number of requirements to be taken into account.

1) What specifications, codes or local regulations are applicable?
2) What crane capacity is required?
3) What is the required span?
4) What is the lift required by the hoist?
5) What will be the duty cycle (usage) of the crane?
6) What is the hoist weight? Do you need the use of a second hoist on the bridge crane?
7) What is the hook approach required?
8) What length of runway system is desired?
9) What factors need to be considered in the design of runway and building structure?
10) What will the operating environment be (dust, paint fumes, outdoor, etc)?
11) What are the necessary crane and trolley speeds?
12) What is the supply voltage/phases/amperage?
13) What control system is desired?
14) Is there existing cranes on the runway?

15) What safety considerations are to be followed?

16) Consider maintenance aspects of the crane.

17) Consider other accessories such as lights, warning horns, weigh scales, limit switches, etc.

But before we discuss further, you have need to know a general clarity of the terminology used in the overhead crane industry.

Ok..wait for the next post..see you!!

Factors To Consider When Purchasing A Crane 2010

Hello to my readers..

If you own a business in one of these industries, the choice of a crane is critical for the success and efficiency of your business. So, here are some important factors that you must take into account for buying a crane.

Types of Crane

To begin with, you must know the different types of cranes available in the market. You must decide whether you need a mobile or fixed crane. You must also learn about overhead cranes, gantry cranes, monorail cranes, material lifting cranes, heavy duty cranes and other options to decide which one suits your requirements.

Lifting Capacity

An important consideration while choosing a crane is the maximum weight lifting capacity specified by the manufacturer. Different applications require materials with different weights to be lifted. So, the crane you select must be capable of supporting the maximum weight to be lifted at your workplace. Make sure that you dont oversize the capacity of the crane purchased.

Usage Limit

Another deciding factor to buy one of the industrial cranes is the limit of its usage. You must know how many times the crane would be used per hour or per shift. Besides, you must also know the shifts per day and the days per week for which the crane would be used. This should help you choose the crane that withstands a particular usage limit.

Learn about Components

Cranes with different components are suitable for different working environments. So, you must take into account the components like mechanical components and electrical components. Besides, you must also learn about the motor controls and operator controls to ensure that the right crane is purchased.

Speeds and Distances

Learn about the speed with which the crane lifts a particular quantity of eight. At the same time, you must learn about the maximum height or horizontal distance that the crane can move. All these factors help you choose the suitable industrial cranes that add efficiency to your working style.

Maintenance Required

Finally, you must consider the maintenance required for different parts of the crane, including motors, gearboxes, bearings, wire ropes and so on. Ask for warranty from the seller of industrial cranes.

Taking all these things into consideration should help you invest money in right types of gantry cranes, heavy duty cranes or other cranes.

Ok, thats all for this post..
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