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1. Scope
of Application
This specification specifies a test and examination
method for a factory producing a small centrifugal pump. The
range of pump shall be a section from the suction flange(or
the bell-mouth attached to the pump body) to the discharge flange.
2. Test Item & Examination Item
2-1 Test Item - Test items are as follows;
Total pump head, discharge, revolution, brake horse power, suction,
operation
2-2 Examination Item - Examination items are as follows;
(1) Total pump head, discharge, brake horse power, pump efficiency,
operation, water pressure
(2) Total shut-off head(if necessary), suction of the highest
point in total head curve, scope of use, suction
3. Terms of Test
3-1 Test Water - For the test, the clean water at room temperature
shall be used.
Room temperature is 0 to 40℃, and at that time, the weight per
the unit
volume of clean water is 1kgf/L(density is 1000kg/㎡).
(1) If the test water is above 40℃ as clean water or the weight
per unit volume of the specified water is different from that
of the room temperature water,
the result of test shall be converted to the capacity of test
water.
(2) If the viscosity of the test water or solid matters are
contained in it, the capacity of the pump water at room temperature
shall be determined in advance.
3-2 Revolution - Revolution for the test shall be
as follows;
(1) Revolution for the test shall be the specified revolution.
(2) If the specified revolution cannot be met due to circumstances
of the test facility, another revolution may be applied within
±20% of a specified revolution.
(3) It it is impossible to test in the range of (2) with a
high power pump, a specified revolution may be decreased up
to -30% according to an agreement of the parties concerned(it
will be referred as "agreement" in below).
(4) In case of running a subsidiary gear, a specified revolution
is a revolution generated when a pump is run with specified
load at normal power
supply(frequency, voltage).
3-3 Measuring Point
For a test of centrifugal pump, measure the discharge for
more than 5 kinds from shut-off condition to much quantity
if possible, and measure at least one kind of discharge in
a lower head than a specified head.
4. Test Equipments
Test equipments shall be enough for testing the
capacity of a pump. At that time, a discharge measuring device
shall be determined by provisions of KS B 6302(method of measuring
the pump discharge.)
* The following figure shows an example of test equipments
5. Method of Test
Drive a pump by the test revolution and test it
varying the total head and the suction by adjusting a valve
in the side of the discharge.
5-1 Total Head
1-1 Gauge - Gauges used for measuring the pressure
shall be as follows;
(1) Bourdon tube pressure gauge and vacuum gauge
(2) Manometer
(3) U-Mercury Manometer
(4) Other pressure gauge
1-2 Measurement - Measure in accordance with the follows
and read the specified total head by 1/100.
(1) If the pressure is more than the atmosphere pressure,
extract the air throughly from a tube which connects a gauge
with a pump pressure measuring hole, fill it with the clean
water, and then read the indicator of gauge. For doing so,
use a trigonal cock or an air vent valve for the pressure
gauge, use an air vent valve for the manometer or the U-mercury
manometer(they will be referred as 'a manometer' in below.),
and then, check the air extracted thoroughly in operating
them.
5-2 Discharge
Discharge of a pump is the effective
liquid measure(㎡/min) discharged from
the pump discharge flange in an unit time. But, it depends on
an agreement
whether the discharge includes the liquid measure drawn out
due to another purpose before it reaches the pump discharge,
or not. And, the water, such as leaking water, pump bearing
cooling water, water for balancing the pressure, and water for
preventing the leakage, is not included in discharge
Measurement - The measurement shall be performed as specified
in KS B 6302.
5-3 Revolution
Measure it with an exact revolution indicator, write
down the value by 1/200, and measures it repeatedly
many times so that the average will be the revolution.
5-4 Brake Horse Power
This can be found by measuring the exact input of
a motor by exact test or by measuring a dynamometer,
and shall be expressed as Kw in principle. Read all of values
for finding brake horse power by 1/100.
5-5 Suction
This shall be the suction in specified total head,
and shall be checked whether the head will be lowered
by cavitation and whether there is any noise.
* Remarks : Particularly, finding the necessary
NSPH by designation, the value of NSPH, found when
total head is lowered 3% than ordinary time, shall be regarded
as the necessary NSPH for discharge.
5-6 Operation
1-1 Oscillation & Noise - Check oscillation
& noise at specified operation.
1-2 Temperature of Bearing - Measure the temperature
of bearing.
6. Table of Test Results
The table of test results shows tested revolution
and values measured by the test water. You shall record
clearly the size or type of pump, manufacturer,
manufacture no., test no., orderer, outline of
specifications, date of test, tester, method of
measuring the suction, items for the gearing of motor, etc.
Draw a capacity curve on a graph paper by placing
the discharge at the horizontal axis and placing
total head, brake horse power, pump efficiency,
and revolution at the vertical axis on the basis of
converted values.
7. Method of Test
7-1 Total Head & Discharge
Total head and discharge of a capacity curve shall
be determined by the following basis 1 or 2 at a
specified point(point which indicates specified total head and
specified discharge).
1) Basis of determination : At a common pump, the
discharge for total head shall be the same as or more
than the specified discharge.
2) Basis etermination : When the allowed limit of
total head or the discharge is restricted especially,
either of total head or the discharge
on the capacity shall be met. But, this is an allowed value
for a
specified point, so, it doesn't restrict
other points except a specified point.
7-2 Brake Horse Power
Brake horse power shall exceed the specified power
for the specified discharge.
1) If the limit of operation is specified, the specified
power for the limit of operation shall not be exceeded.
2) If a resistance curve of equipments is specified,
the specified power shall not be exceeded, for the
discharge at an intersection point of the resistance curve of
equipments and a pump head curve.
3) If a resistance curve of equipments is not clear,
the specified power for the specified total head shall
not be exceeded.
7-3 Pump Efficiency
For a specified revolution and a specified total
head, the pump efficiency shall be found by the following
calculation, and when the value is lower than the
guaranteed efficiency(n n%), the permitted value shall
be (6-0.05n n%) |
n
=LW/L×100
Here, n = pump efficiency(%)
L : brake horse power(Kw)
Lw : water power
The method of finding water power is,
Lw = 0.163rQH
r : weight per an unit volume(KgF/L)
Q : discharge(㎡min)
H : total head(m)
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7-4 Operation
Test as specified in 5.6.1, Oscillation & Noise,
and the operation shall be smooth, oscillation of each unit
shall be insignificant, and any wrong noise shall not be generated.
*Remarks : Particularly, oscillation of the bearing unit
needs more attention.
*Reference
1. A diagram indicating the standard value of
pump oscillation shall be marked on the table of oscillation
standard value. This standard value
is for a centrifugal pump with normal horizontal and vertical
axes,
and a pump with special structure is not included.
2. Oscillation is changed by the fixing condition,
and as the fixing condition is weaker, it is usually larger.
So, it is desirable to get oscillation
with the same degree as the practice in the test. But, if that
is
impossible due to a pump type or the
circumstances of test equipments, the value of practical oscillation
may be determined
by an agreement.
*Remarks : If the discharge is drained out by a discharge
valve directly after pumping, much attention
shall be paid because oscillation of the pump may
be affected by oscillation of a discharge valve caused
by draining out.
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The horizontal axis : Oscillation in the middle of bearing
The vertical axis : Oscillation in the middle of bearing
at the upper part of a gear.
Temperature of bearing : Maximum temperature allowed
to a bearing and the allowed rise of
temperature shall be as the following table. |
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Allowed
rise of temp. ℃(K)
(If the peripheral temp. is lower than 40℃, the temp.
shall not exceed the allowed max. temp.) |
Allowed
max. temp. ℃ |
| |
On
the surface of a bearing |
Measuring
by putting a thermal sensor into the metal thermometer |
On
the surface of a bearing |
Measuring
by putting a thermal sensor into the methyl thermometer |
Defueling
temp |
| Natural
coolingNormal lubricant |
40 |
45 |
75 |
80 |
- |
| Natural
cooling heatproof lubricant |
55 |
60 |
90 |
95 |
- |
| Water cooling-type |
- |
Agreement |
- |
80 |
- |
| Forced
lubricating |
- |
- |
75 |
80 |
80 |
| Normal
lubricating |
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7-5 Finishing Total Head
Finishing total head shall be higher than the practical
height of an equipment using a pump. If the
practical height is not known or more than two pumps
need parallel running, the finishing total head shall
be higher than the specified total head.
Allowed value, in case that the value of finishing total head
is guaranteed, depends on an agreement.
7-6 Total head
Discharge on the highest point of total head curve
shall be lower than the specified discharge.
7-7 Scope of use
Allowed value, in case that the value of a point
except a specified point on total head curve, shall meet
the value of an agreement.
7-8 Suction
The head shall be lowered by cavitation and any noise shall not be generated.
7-9 Water pressure
In principle, the test shall be performed with 1.8
times pressure of the specified pressure for 3 minutes
and there shall not be any problem of leakage. But,
the min. water pressure for a test shall be 1.5Kgf/㎠
(0.15MPa).
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