Mining Crushers Breakdown
Páginas: 23 (5617 palabras)
Publicado: 10 de agosto de 2012
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Author: Graham Townsend
Product Support Manager
Regional Sales Support Group
Metso Minerals (Asia-Pacific)
Level 2, 1110 Hay Street
West Perth WA 6005
Ph: (08) 9420 5555
Fax: (08) 9320 2500
graham.townsend@metso.com
October 2001
All materials contained hereinremain strictly the intellectual property of the author. Permission to reproduce or modify for general circulation any part of this document on any medium, electronic or otherwise, has to be sought from the author in writing. Under international copyright conventions, failure to do so will leave offenders liable to prosecution possibly in more than one country.
Introduction
All machines can fail.This paper will focus particular attention on rock crushing equipment, particularly the cone crusher. Cone crushers, like many other machines, can fail for a variety of reasons and the costs associated can be both direct and indirect. The main reasons for failure are:
1. Design
2. Assembling
3. Maintenance4. Application / Operation
Let's highlight a few facts prior to assessing the application and operation of these machines.
Design
The Original Equipment Manufacturer (OEM) will always design a machine to meet or exceed the duty specified. In the case of the cone crusher, the three major design limits are Power, Volume and Crushing Force.
The Power is limited to the sizeof the installed power, which is located on the nameplate on the electric or alternative powered motor. Normal operating range is from 0% to 90% of motor full load rating. The remaining 10% is left to accommodate spikes or surges in load due to feed variations to the crusher.
The Volume limit is the maximum through put or feed to the machine before it starts to overflow or back up the chute.This is commonly known in the industry as "choke fed".
The Crushing force is the maximum force that can be exerted to the rock. Once this force is exceeded, the outer crushing chamber will move or the setting will increase for head supported machines. This is known as ring movement, ring bounce or tramping.
The design engineers will set these parameters for each machine in their designcalculations. All components will be factored to endure these loads and cycles. This ensures trouble free, long service life and optimum availability. Once in the field, time and evolution ensures the product is fit for purpose. Some designs are still in operation today after some 60 years of operation.
Once the machine has been designed correctly, we then need to look at the assembling of themachine.
Assembling
The assembling of the machine is critical, and for new machines it is a simple procedure of following both the OEM's manuals and the use of good fitting practices. For machines that have suffered a failure, a little more care is required to ensure the problems are solved prior to operation.
The assembling of either a new or failed machine consumes a very small amount oftime compared to its operational period. A machine once put into service will operate for many years before requiring a full pull down. Even if the machine is pulled down every twelve months for a routine inspection, depending on the actual machine size, the shutdown period may be 1 to 3 days. As a percentage against operation time, this will be 0.2% to 0.8% of operational or available time. It isimportant to conduct the shutdown by well-trained and supervised tradesman, and only use OEM spare and wear parts that are specially engineered and proven for the job.
Let's now assume the machine is assembled correctly with fit for service OEM parts.
Maintenance
As with all machinery, especially those in harsh environments, routine inspections and regular maintenance must be implemented....
Author: Graham Townsend
Product Support Manager
Regional Sales Support Group
Metso Minerals (Asia-Pacific)
Level 2, 1110 Hay Street
West Perth WA 6005
Ph: (08) 9420 5555
Fax: (08) 9320 2500
graham.townsend@metso.com
October 2001
All materials contained hereinremain strictly the intellectual property of the author. Permission to reproduce or modify for general circulation any part of this document on any medium, electronic or otherwise, has to be sought from the author in writing. Under international copyright conventions, failure to do so will leave offenders liable to prosecution possibly in more than one country.
Introduction
All machines can fail.This paper will focus particular attention on rock crushing equipment, particularly the cone crusher. Cone crushers, like many other machines, can fail for a variety of reasons and the costs associated can be both direct and indirect. The main reasons for failure are:
1. Design
2. Assembling
3. Maintenance4. Application / Operation
Let's highlight a few facts prior to assessing the application and operation of these machines.
Design
The Original Equipment Manufacturer (OEM) will always design a machine to meet or exceed the duty specified. In the case of the cone crusher, the three major design limits are Power, Volume and Crushing Force.
The Power is limited to the sizeof the installed power, which is located on the nameplate on the electric or alternative powered motor. Normal operating range is from 0% to 90% of motor full load rating. The remaining 10% is left to accommodate spikes or surges in load due to feed variations to the crusher.
The Volume limit is the maximum through put or feed to the machine before it starts to overflow or back up the chute.This is commonly known in the industry as "choke fed".
The Crushing force is the maximum force that can be exerted to the rock. Once this force is exceeded, the outer crushing chamber will move or the setting will increase for head supported machines. This is known as ring movement, ring bounce or tramping.
The design engineers will set these parameters for each machine in their designcalculations. All components will be factored to endure these loads and cycles. This ensures trouble free, long service life and optimum availability. Once in the field, time and evolution ensures the product is fit for purpose. Some designs are still in operation today after some 60 years of operation.
Once the machine has been designed correctly, we then need to look at the assembling of themachine.
Assembling
The assembling of the machine is critical, and for new machines it is a simple procedure of following both the OEM's manuals and the use of good fitting practices. For machines that have suffered a failure, a little more care is required to ensure the problems are solved prior to operation.
The assembling of either a new or failed machine consumes a very small amount oftime compared to its operational period. A machine once put into service will operate for many years before requiring a full pull down. Even if the machine is pulled down every twelve months for a routine inspection, depending on the actual machine size, the shutdown period may be 1 to 3 days. As a percentage against operation time, this will be 0.2% to 0.8% of operational or available time. It isimportant to conduct the shutdown by well-trained and supervised tradesman, and only use OEM spare and wear parts that are specially engineered and proven for the job.
Let's now assume the machine is assembled correctly with fit for service OEM parts.
Maintenance
As with all machinery, especially those in harsh environments, routine inspections and regular maintenance must be implemented....
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