Compressor Mounting

7/29/2019 Compressor Mounting

1/41

Best Practices in

Compressor Mounting

By:

James A. KulyChief Engineer

ITW Polymer Technologies

Montgomeryville, Pennsylvania

7th Conference of the EFRC

Florence, Italy


2/41

A Compressor In Slow Motion

Courtesy of Beta Machinery Analysis

http://www.betamachinery.com/


3/41

Introduction

The purpose of the mounting system on areciprocating gas compressor is simple:

Position and support the compressor, its

driver and related equipment.Effectively transmit the vibration produced

by dynamic forces down through the

foundation while reducing or eliminating the

harmful effects of those vibrations.

Accomplish items #1 and #2 above for 30

years or more.


4/41

There is Only One Problem

Reciprocating compressors have very high

operational forces that act in all directions


5/41

Solution = FEA + Experience

Courtesy of Southwest Research Institute

http://www.swri.org/default.htm


6/41

Best Practices Related To

Foundation Construction

Frame, Rail, Sole Plate and FoundationPreparation

Anchor Bolts, Nuts and Washers

Anchor Bolt Holes / Sleeves / Covering /Sealing

Expansion Joints

Epoxy Grout & Chocks

Coating and Sealing the Foundation


7/41

Compressor & Its Foundation

Are a series of

interacting

structures thatmove and vibrate.

Objective is to

make them into atightly integrated

structure.

CHOCKCHOCK

EPOXY GROUT

CONCRETE FOUNDATION

ENGINE /

COMPRESSOR

CONCRETE MAT

CHOCK

CHOCK

EPOXY GROUT

FOUNDATION

COMPRESSOR/ ENGINE

MAT


8/41

Straight vs. Skid Mount


9/41

Constructionof the Foundation

Foundation Weight = 4 to 8 times Compressor WtFoundation Width = > 1.5 times Foundation Height.

Width

Height

Mechanical

isolation

15 to 20 cm

MDFCVC

Minimize

FCG

MF

CG

Foundation/Mat CG (FCG) of theblock < 15-20 cm (6-8) from thecrankshafts vertical centerline(CVC)

Minimize the elevation differencebetween the MDF and MFCG

Mechanically isolate the foundationblock from any surroundingstructures.


10/41

Constructionof the FoundationDense rebar in the

upper third of block

#6 Rebar on 6" Centers

#6 Rebar on 12"

centers in lower 2/3's

of foundation

Extra reinforcement

around anchor bolts

Anchor bolts terminating

half way into the mat

Diagonal

rebar at all

re-entrant

angles

Heavy rebar

into the mat


11/41

Foundation Design & Installation

High quality concrete withcrushed stone

Increase tensile strength withsteel fibers

Allow concrete to fully cure

Avoid cold joints

NO sharp internal corners

Avoid vertical connectionsAvoid edge lifting

X

Y

When Y < XOption 2 - Round Edge of Concrete

X45.0

X

Y

When Y < XInstall Pins Along Edge of

Concrete

T

T

2/3 Y


12/41

Frame, Rail, Sole Plate and

Foundation Preparation

Clean, Clean, Clean

Sandblast metal to a minimum SP6 & Solvent

Wash

Chip concrete exposing 50% chipped & broken

aggregate

NO coatings

Steel

Epoxy Chock Steel

High Friction

Resistive

Force

Normal

Force

COF = 0.7

Coefficient

of Friction=

Normal Force

Resistive Force


13/41

Anchor Bolts

Grade: 4140 ASTM A193 B7 Grade 8.8

Length: 1.2 m (48 inches)

Terminate anchor bolts in the matAllow 12 times the diameter or 40% to 50% of

the length of the bolt to free-stretch

Allow 10 times the bolt diameter to be

embedded


14/41

Nuts and Washers

Nuts

Grade: ASTM A194

2H - High StrengthWashers

Spherical Washers


15/41

Tensioning

Nuts Hand-Tool tight until grout hardens

Tension Bolts with Hydraulic Bolt Tension

Design for a maximum epoxy chock / groutloading is 6.9 MPa (1,000 psi)

Tension bolts to maximum of 65% to 70%of their yield strength

Re-tighten after compressor & driver havecome up to temperature


16/41

The Benefits of Bolt Tension

Stored Energy

Low Pretension

x

2x

Stress

Tension

inth

eBolt

Stored Energy

High Pretension

Stored Energy Increases asthe Square of the Tension

Decompression Point -

High Pretension

Decompression Point -

Low Pretension

StrainChange in Length

Tension Applied to the Mounting Flange

Elastic

Range


17/41

Types of Anchor Bolts


18/41

SuperBolts & MagBolts

Other types of bolting

options offer more

accurate bolt tension


19/41

Anchor Bolt Holes / Sleeves /

Covering / Sealing

Rule of Thumb

12 x Bolt Diameter for Free

Stretch

10 x Bolt Diameter installed

Upper portion

PVC bolt sleeve

Corrugated plastic

Metal pipe

Lower portion in concrete or epoxy grout


20/41

Other Bolting Arrangements


21/41

Skid Mounting Methods


22/41

Expansion Joints

Proper Layout based onGrout manufacturers

recommendation

Differences in seasonaltemperatures

Install Grout Holes

Correct Joint MaterialsWell Sealed


23/41

Alignment Tools

Many differenttypes

Should haveround landingplates with roundedges

NEVER leavethem inside thegrout


24/41

Epoxy Grout

3- Component, Non-shrink GroutEpoxy Grout is Best

Best Practice full bed of epoxy grout with

individual epoxy chocks for anchor bolts

Install without stress risers


25/41

Preparation and Pouring


26/41

Poured-in-Place Epoxy Chocks

2 Component Epoxy Chocking Compound

is Best

NO Stress Risers in ChockMUST Manage Epoxy Temperature

Overpour is important use a metal dam

Foam Strip

Depth above bottom of mounting foot


27/41

Individual Chocks


28/41

Vibratherm Chocks


29/41

Coating and Sealing the Foundation

After Grouting Seal Surrounding Concrete

Prepare surface

Address cracks & expansion jointsEpoxy Primer & Epoxy Top Coat

Seal Mounting feet & Sole Plates

Seal Expansion JointsInstall Drip Pan


30/41

Conclusion

Installation Best Practices should be

Accumulated & Recorded

Confirmed andConsistently Applied


31/41


32/41


33/41


34/41


35/41


36/41


37/41


38/41


39/41


40/41


41/41

Thank You

Contact

[email protected]

Documents

Compressor Mounting