Page 81 - Improving Machinery Reliability

Chapter 2

Vendor Selection

and Bid Conditioning

Selecting Major Machinery Vendors

It goes without saying that quality and reliability of rotating equipment for process
plants are largely determined by the slate of vendors selected to submit cost propos-
als. Even the best specification may be lost on a vendor who lacks the skill, experi-
ence, resources, and follow-up organization needed to carry out the manifold
detailed engineering, manufacturing, and quality-control steps that will culminate in
a high-quality product.
Whenever possible, inquiry specifications should go only to vendors who meet
these criteria. If a vendor can demonstrate compliance with the specified require-
ments and can stand the test of a rigorous bid comparison with his respective com-
petitors, the purchaser should not be reluctant to place an order with this vendor.
Subjective judgments should be left out of the selection process, and only tangible
evidence of experience, capability, and past performance should be weighed. Of
course, there will never be any substitute for plain old common sense and soundly
conducted engineering reviews. This is especially so when prior experience simply
doesn’t exist or if there are compelling reasons to buy machinery incorporating pro-
totype components, novel manufacturing techniques, etc.
We know of relatively few procurement situations in which capable vendors
would not be able to demonstrate satisfactory experience for the service conditions
imposed on the proposed machinery. Service conditions include parameters such as
molecular weight, viscosity, volumetric capacity, power rating, speed, temperature,
and pressure. Similarly, capable vendors can usually demonstrate mechanical-design
experience for applicable critical parameters that could include, but not be limited to:
Bearing span
Bearing design, loading, size, and clearance
Blade design
Casing size and design, and exhaust orientation
Casing-joint design configuration, gasketing, and bolting
Coupling design and arrangement

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