KIRLOSKAR KC Series User Manual

22
6. PARALLEL OPERATION OF COMPRESSOR
GENERAL
Whenever two or more compressors are installed with
common suction header piping and these compressors
are operating simultaneously, the operation is called as
parallel operation of the compressor. In this case,
discharge line of individual compressor may be either
connected to common discharge header or separately to
individual condensers.
During operation, the oil return from evaporator(s) will
not be uniform to the crankcases of different
compressors. This may cause shortage of oil in some
compressors and excess in other, leading to failure of
compressor. To overcome this situation following
precautions are necessary to be taken during
installations :
INSTALLATIONS PRECAUTIONS
1. See that all compressors are installed in same
horizontal level.
2. Connect all compressors by oil equalizing line with
isolating valve in between each pair of compressor.
Oil equalizing line must run in level with oil
equalizing tapping or below the oil level of the
compressor. Under no circumstances this line
should run at level higher than compressor oil level.
3. Connect all compressors by crankcase gas
equalizing line with isolating valve in between each
pair of compressor. Under no circumstances this
line. should run below than that of crank case gas
equalizing tapping provided on crankcase.
4. For multiple condensing units interconnect all
condensers to equalize condensing pressure with
proper isolating valves.
A construction whereby just one horizontal line with
ample diameter, fitted between two adjacent
compressors onto their sight glass connections, serves
both purposes, viz to maintain equal oil levels as well as
equal crankcase pressure. See figure 25 for reference.
Figure 25
No extra gas equalizing lines are necessary because the
vertical location of the oil equalizing line is such, that
the prescribed oil level in the crankcase is approx, half
way this line thus leaving ample passage to equalize the
crankcase pressures as well.
A stop valve in the equalizing line should be mounted
with the spindle in a horizontal position in order to avoid
the interruption of the oil level , when the valve is open.
We can supply a set of oil and gas equalizing line
consisting of
a) TAL valve type 40.
b) Tee connection left
c) Tee connection right
d) Joining 40 NB steel pipe
The number of parallel compressors to be
interconnected in this way should be restricted to three,
whereby the length of the equalizing line between the
sight glasses of two adjacent compressors should
preferably not exceed 2 mtrs.
Moreover, it is recommended always to provide each
compressor with an individual oil separator and
corresponding oil return line to its crankcase.
OPTIONAL INSTRUCTIONS:
1. Before starting all these parallel connected
compressors, OPEN fully. isolating valves installed
in gas and oil equalizing line and then follow other
instructions for starting the plant.
2. If one of the compressor needs to be cut off from the
operation CLOSE fully isolating valve related to the
compressor to be cut off and then follow other
instructions for stopping the concern compressor.
245
OIL LEVEL
SIGHT
GLASS
STEEL PIPE
Ø48.3x2.6 mm
TEE CONNECTOR
RIGHT HAND TYPE
SIGHT GLASS
TEE CONNECTOR
LEFT HAND TYPE
STOP VALVE
TYPE TAL 40
MAX 2000
140
147

KIRLOSKAR KC Series Specifications

General

Brand	KIRLOSKAR
Model	KC Series
Category	Air Compressor
Language	English