1

Maintenance of Reciprocating Compressor

.

2

- Components of Compressor -

PISTONPISTON ROD

CROSSHEAD

CONNECTING ROD

CRANKSHAFT

CYLINDERCROSSHEAD GUIDE FRAME

3

- Installation Flow -

Crankshaft

Main Bearings

Crosshead & Connecting Rod

Rod Packing

Piston

Compressor Valves

Coupling / Alignments

Bar-over Test

Ass

emb

le

Dis

asse

mb

le

4

- Location of Bearings -

CROSSHEAD PIN BEARING / BUSHCRANK PIN BEARING

CROSSHEAD SHOE

MAIN BEARING

5

- Disassembling of Main Bearings -

Disassemble frame tie rod

Remove the cap with upper metal

W ie r Rope

Se t Screw Lowe r Me ta l

Uppe r me ta l

Eye Bo l t

Install special tool into oil hole of crankshaft

Turn the crankshaft and remove the lower metal

To Tu rnD isa ssemb l ing Too l C rank Sha f t

Lowe r Me ta l

6

- Assembling of Main Bearings -

Assembling lower metal

Assembling crankshaft

Assembling upper metal with cap

Tighten the upper cap by torque wrench

(820 N-m)

7

- Construction of Crosshead & Connecting Rod -

8

9

- Assembling of Connecting Rod -

Assembling of connecting rod can be done by the opposite flow of assembling.

However, tightness of big end bolts are controlled by its elongation.

So, please measure its length before and after installation.

10

- Disassembling of Crosshead -

After disassembling of piston and connecting rod.

Tilt the crosshead by 90 ﾟ and take out crosshead from window of crosshead guide or compressor frame.

11

- Assembling of Crosshead -

In case of assembling of crosshead, please take care that there are two type of crosshead shoes.

One is “C”shoe and the other is “O” shoe.

And after assembled to the crosshead guide, clearance between crosshead and crosshead guide to be recorded.

Planned clearance is 0.20 – 0.29mm and the using limit is 0.40mm.

O Shoe C Shoe

C Shoe O Shoe

Clearance

：Measu r ing Po in t

12

- Measurement of Crank Arm Deflection -

270 ﾟ

90 ﾟ

180 ﾟ

0 ﾟ1. Set the deflection gauge

(special dial gauge) between each crank arm at 0 ﾟposition.

2. Turn and measure the movement at 90 ﾟ , 180 ﾟ , 270 ﾟ .

3. For example, if the measured deflection is 0 – +0.06mm, jack up the turning gear at the half of the measured value of 0.03mm.

4. Adjustment limit is 0.03mm and using limit is 0.06mm

13

- Construction of Cylinder -

PISTON ROD PACKING

DISCHARGE VALVE

SUCTION VALVE UNLOADER

CLEARANCE POCKET

SUCTION VALVECYLINDER LINER

PISTON

14

- Construction of Piston Rod Packing-

● Piston rod packing

Rod packing

Packing case

Tie bolt

Gater Spring

15

- Assembling of Piston Rod Packing -

FRAME S IDE

No .1&2R1 R0T1

R0R3 T5No .3&4

T5T5No .5

(a)

(b) (c)

There are three types of packing.

・ Butt-cut type (a)

・ Step-cut type (b)

・ Backup ring (c)

Please take special care for the direction & combination of packings.

Incorrect direction or combination will cause the leakage of gas.

After assembled to packing case, please measure the side clearance and record it.

16

- Construction of Piston -

● Piston ring

●Rider ring

● Piston rod ● Piston nut

17

- Assembling of Piston -

CHA IN BLOCK

P ISTON RODWRENCH

REMOVE THE NYLON SL ING

CYL INDER

ROD PACK ING PROTECTOR

AFTER INSERT ING ROD

WE IGHTLENGTH a

a

1ST A /B : 208 kg1ST A /B : 2145

Pro te c t ing Capfo r P i s ton Rod Pa ck ing

Assemble piston rod & piston rings to piston

Set piston rod wrench to piston nut & set protector for the

threaded portion of piston rod

Then, hoist the piston assembly and install into cylinder

Inserting the piston assembly, install the rider rings to piston

Screw in the piston rod to crosshead

18

- Assembling of Piston -

Adjust the screw travel by markings on piston rod and crosshead by using divider.

Then, tighten cross nut.

The reference length indicated on window of crosshead guide

Measure the clearances between piston & cylinder liner for four

directions

Assemble cylinder cover

Carry out bar-over test

(End clearance, runout)

19

- Assembling of Piston Rings -

(1) Two PPS ring form one set. In case of exchange exchange as set not one ring alone.

(2) At installation, install the piston rings in the direction parallel with piston axis. Don’t install from direction “b”.

(3) After assembled to piston, measure and record the side clearance.

(4) When assembling, locate the two rings 180 ﾟ apart each other.

P i s ton R ing P i s ton Body

D i rec t ion "a "

D i rec t ion "b "

× ○

20

- Maintenance of Rings -

P is ton

P is ton R ing

In i t ia l Wea r L im i t

(1) Wear limit of piston rod packing is 3mm at the height of the ring. In case of replacement, do not replace one ring alone. The planed life of rod packing is 8000hrs, so maintenance required within 8000hrs.

(2) The planned life of piston ring is also 8000hrs however, only for initial operation, we recommend you to overhaul at 4000hrs to estimate the actual life.

21

- Maintenance of Rings -

Gap

0 .5mm

Wea r L im i t

×

×

×

×

×

Dimention

T ime

L i fe Expec ted Nex t Check

(1) The wear limit of rider ring is by the bottom clearance between piston and cylinder liner becomes 0.5mm. The planned life is 8000 hrs, however, for initial maintenance, we recommend you to carry out overhaul at 4000hrs to estimate the actual life.

(2) To determine the life, please plot the clearance versus operation time like the below graph.