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NLT series condensate pump

key word:Heat exchange element

Category:


Product description

NLT series condensate pump

 

1. Introduction

1.1. Application

NLT series condensate pumps have high efficiency and operation reliability. They are suitable for use as condensate pumps or condensate booster pumps in thermal power generating units. They can also be used to transport other liquids similar to condensate. The temperature of conveying medium is not more than 100 ℃.

1.2. Model meaning

NLT-**-##-&&-@@-$$

NLT --- code of NLT series condensate pump

**---------Nominal size of pump outlet diameter (mm)

##------------Impeller diameter nominal size (mm)

&&-----------------None

@@----------------------Impeller series

$$--- when this item is available, it means that the first stage is a double suction structure

1.3. Structural features

1.3.1. Structure type: NLT series condensate pump is vertical multi-stage centrifugal pump with barrel bag shape.

1.3.2. Structure description:

1.3.2.1. In order to make the pump have good anti cavitation performance, the first stage impeller is specially designed and used in combination with the inducer or double suction structure.

1.3.2.2. On the premise of meeting the pump performance and stiffness, the axial guide vane is adopted to reduce the radial size of the pump

1.3.2.3. The core pulling structure is adopted for the parts below the pump foundation, which makes the disassembly and repair of the pump convenient

1.3.2.4. The axial force of the pump is mainly balanced by the balance hole and balance chamber on each stage impeller, and the remaining axial force is borne by the thrust bearing components.

1.3.2.5. The thrust bearing is set on the pump, and the elastic coupling is used between the pump and the motor, which makes the pump centering and field installation convenient.

1.3.2.6. According to different requirements of users, mechanical seal, packing seal or floating seal can be used for shaft seal of pump.

1.3.3. Description of important parts:

1.3.3.1. As shown in Fig. 14-1, the first stage impeller adopts the double suction impeller, and the upper and lower inlets can flow in, thus increasing the inlet flow area.

1.3.3.2. Secondary impeller. The secondary impeller adopts balance hole and balance chamber to balance axial force. Its structure is shown in Fig. 14-2,

1.3.3.3. Thrust bearing. The thrust bearing components of the pump (see Fig. 14-3) are adopted. The structure mainly includes thrust pad (with disc spring and accessories), guide pad, thrust head, bearing plate (for thrust pad support), large end face, shell, bottom plate, etc.

The bearing is a self-lubricating bearing, which is cooled by water through the cooler installed in the bearing. The lubricating oil flows into the bearing plate and the oil baffle tube in the bearing through the groove designed on the bottom plate. After entering the working face of the thrust pad and the guide pad, it flows out from the oil outlet hole on the outer oil baffle tube. After recycling through the oil cooler, the inlet temperature of the cooling water is not higher than 38 ℃.

1.3.3.4. Foundation slab. The improved foundation slab is shown in Fig. 14-4 (a) and the improved double-layer foundation slab is shown in Fig. 14-4 (b). After the improvement, the rigidity of the pump group is increased by more than 3 times, so as to meet the requirements of safe and stable operation of the pump.

1.3.4. Description of important characteristics:

1.3.4.1. The vertical structure of tube and bag makes installation, disassembly and maintenance convenient. The selected bucket bag structure has structural rigidity, and the part below the foundation adopts core pulling structure. There is no support rib plate between the core pulling component and the outer cylinder, which will not cause transverse vibration due to mutual interference. Meanwhile, the installation, disassembly and maintenance of the pump are also very convenient.


1.3.4.2. The unique first stage impeller design ensures good cavitation resistance. The first stage impeller adopts double suction or inducer structure, which reduces the eddy current at the inlet, effectively improves the anti cavitation performance of the pump, expands the safe operation range of the pump flow, and makes the pump run stably, with low noise and low loss. At the same time, the axial force can be effectively balanced in the design of double suction impeller. In addition, the first stage impeller is made of anti cavitation material, which ensures good anti cavitation performance.

1.3.4.3. The independently installed pad type thrust bearing on the pump side ensures the normal operation of the pump. After adopting the independently installed thrust bearing, the elevation of the center of gravity of the pump group is reduced, and the operation stability of the pump group is improved. Moreover, the motor does not need to bear the thrust of the pump, so the stability is high. The elastic coupling can be used to connect the water pump and the motor, so the installation, disassembly and alignment of the unit are convenient. The complete oil bath lubrication system can avoid complex forced oil system and is easy to maintain.

1.4. Technical level and advantages

NLT series condensate pump has the characteristics of stable performance, high efficiency, low vibration and noise, and has obvious energy saving effect; the condensate pump of 600MW thermal power generation unit has obtained the utility model patent, the patent number is ZL200420114139.0. NLT500-570 × 4S condensate pump won the third prize of China machinery industry science and Technology Progress Award and Shanghai Science and Technology Progress Award in 2006, Shanghai key new product certificate in 2007, Shanghai patent new product certificate and national key new product certificate in 2008

 

2. Main technical parameters and product appearance

2.1. Main technical parameters

2.1.1. Technical parameters of NLT series condensate pump. The technical parameters of typical NLT series condensate pumps are shown in table 14-1. In addition, it can be designed and manufactured according to the special needs of customers.

Table 14-1 technical parameters of NLT series condensate pump

Model Flow Head Efficiency NPSH required Speed Matching power
(m3/h) (m) %) (m) r/min) kW
NLT300-400×4 550 183 81 4.1 1480 400
NLT300-400x5 550 229 81 4.1 1480 480
NL1300-400×6 550 275 81 4.1 1480 630
NLT300-400×7 550 321 81 4.1 1480 710
NLT350-400×2 870 98 82 3.2 1480 200
NL7350-400×4 870 196 82 3.2 1480 710
NLT350-400×5 870 245 82 3.2 1480 900
NLT350-400×6 870 294 82 3.2 1480 1000
NLT350- 400×7 870 343 82 3.2 1480 1120
NLT350-400×8 870 392 82 3.2 1480 1400
NLT400-500×4S 1230 275 82.5 5.3 1480 1250
NLT400-500x5S 1230 330 82.5 5.3 1480 1600
NLT500-570×4S 1760 315 84.5 6.1 1480 2000
NLT500-570×5S 1760 394 84.5 6.1 1480 2300
NLT500-600x3S 2250 258 85 6.3 1480 2100
NLT500-600×4S 2250 344 85 6.3 1480 2700

2.1.2. Type spectrum of NLT series condensate pump. The model spectrum of NLT series condensate pump is shown in figure 14-5.

2.1.3. Performance curve of NLT series condensate pump. The performance curves of NLT300-400 × 6, NLT350-400 × 7, NLT400-500 × 5S, NLT500-570 × 4S and NLT500-600 × 4S condensate pumps are shown in Fig. 14-6 to Fig. 14-10

2.2. Product appearance

2.2.1. NLT series condensate pump structure. The structures of NLT250-370, NLT300-400 and NLT350-400 condensate pumps are shown in Fig. 14-11, and those of NLT400-500, NLT500-570 and NLT500-600 condensate pumps are shown in Fig. 14-12.

2.2.2. Outline and installation dimensions of NLT series condensate pump. The appearance and installation of NLT250-370, NLT300-400 and NLT350-400 condensate pumps are shown in Fig. 14-13, and those of NLT400-500, NLT500-570 and NLT500-600 condensate pumps are shown in Fig. 14-14, and the external installation dimensions of NLT series condensate pumps are shown in table 14-2.

Table 14-2 outline and installation dimensions of NLT series condensate pump

Pump model NLT300-400 NLT350-400 NLT400-500 NLT500-570 NLT500-600
Dimensions
A 4289 3480 5400 6000 7100
B 1693 1841 1070 2140 2494
D 533 970 850 850 1250
E 510 648 850 850 1050
F 700 800 800 1400 900
G 345 425 600 600 800
J 762 762 1220 1300 1300
K 800 820 1300 1400 1400
M 450 700 935 935 935
N 700 700 1200 1200 1200
V 1000 1400 1700 1700 1700
V1 450 700 635 635 635
V2 450 700 935 935 935
W 1000 1500 2000 2000 2000
M1 16 20 24 24 28
M2 16 16 20 24 24
M3 4 4 8 8 8
N1 22 16 36 40 33
N2 33 36 36 36 36
N3 18 18 18 18 18
DN1 411 600 726 800 900
DN2 327.5 350 400 513 500
DN3 61.5 50 94 94 80

 

3. Selection method

When selecting NLT series condensate pump, the data to be provided are as follows:

3.1. Performance parameters

The following data related to the performance parameter requirements of the pump set are obtained as follows and shall be included in the inquiry document of the customer:

3.1.1. Matching requirements of pump quantity and unit capacity.

3.1.2. Pump outlet flow (including design flow and flow range).

3.1.3. Pump outlet head (including design head and head range).

3.1.4. Pump efficiency.

3.1.5. Pump speed.

3.1.6. Pump shaft power limit.

3.1.7. Pump NPSH.

3.1.8. Pump vibration and noise.

3.1.9. Motor voltage, matching power and efficiency, etc.

3.1. Site conditions

The following data related to the site conditions of the pump set shall be included in the relevant documents of the customer:

3.2.1. Unit capacity, pump configuration and operation mode.

3.2.2. Installation location and elevation of pump.

3.2.3. Condenser operating pressure.

3.2.4. Pump inlet conditions:

3.2.4.1. Water level from condenser to pump inlet (including minimum water level).

3.2.4.2. Pump inlet pressure

3.2.4.3. NPSH.

3.2.5. Pump outlet conditions:

3.2.5.1. Center line elevation of outlet pipe.

3.2.5.2. Outlet connection diameter and connection mode.

3.2.6. Pump and motor cooling water conditions

3.2.6.1. Cooling water pressure

3.2.6.2. Cooling water temperature

3.2.6.3. Cooling water quality

3.2.7. Characteristics of transported medium:

3.2.7.1. Density

3.2.7.2. Temperature

3.2.7.3. The water quality analysis report should be provided.

3.2.8. Voltage, response and frequency of the power supply.

3.2.9. Environmental conditions:

3.2.9.1. Outdoor ambient temperature limits.

3.2.9.2. Indoor ambient temperature limit value.

3.2.9.3. Annual mean atmospheric pressure.

3.2.9.4. Annual average relative humidity.

3.2.10. Seismic intensity (including peak ground motion acceleration).

3.2.11. Maximum lifting height and lifting capacity of pump house.

3.3. Supply requirements

If the customer has special requirements, it can be listed in relevant documents, such as:

3.3.1. Product life requirements.

3.3.2. Special material requirements of pump parts, such as outer cylinder and flange.

3.3.3. The scope of supply beyond the termination point specified in "(V) scope of supply and general technical specification for products", such as counter flange and connecting accessories for import and export.

3.3.4. Special performance requirements of motor, such as frequency conversion requirements.

3.3.5. Special motor auxiliary instrument.

3.3.6. Description of self provided motor

3.3.7. Remote control requirements

3.3.8. Any additional measuring instruments, such as pump set vibration monitoring, reversing monitoring instrument, etc.

3.3.9. Special requirements for protection (including paint), packaging and transportation.

3.3.10. Any requirements on the expression language of equipment documents.

3.3.11. Special requirements for site installation guidance service and training.

3.3.12. On site performance test requirements.

 

4. Selection examples

Taking the type selection of condensate pump for a 2 × 600MW unit of a power plant as an example, the selection example of condensate pump is given.

4.1. Site operation conditions and operation parameter requirements

4.1.1. System overview. The condensate system of the project is equipped with 4 condensate pumps.

4.1.2. Equipment installation location. The condensate pump is installed in the center line of - 3.5m.

4.1.3. Equipment use. The condensate pump mainly sends condensate condensate to Deaerator and provides desuperheating water to LP Bypass and Desuperheater of steam turbine.

4.1.4. Meteorological data. According to the data statistics of local meteorological station of the project, its characteristics are shown in table 14-3.

Table 14-3 meteorological data

Zero meter elevation of main power house (m) Local atmospheric pressure  Annual average temperature relative humidity Extreme maximum temperature Extreme minimum temperature Dominant wind direction Peak ground motion acceleration 
(m) (kPa) () % (℃) (℃) g
80320 1003.5 15.9 74 40 -14 The north wind is uniform throughout the year, summer and winter 0.1

4.1.5. Water quality analysis data. See table 14-4 for condensate composition.

Table 14-4 condensate composition.

No. Ingredients Content No. Ingredients Content
1 Total hardnessμmol/L appa. 0 6 Oilmg/L appa. 0
2 Dissolved oxygenμg/L 20 7 PH Value 8.09.0
3 Feμg/L 10 8 Conductivity
25℃,μs/m
0.2
4 Cuμg/L 5 9 Naμg/L 5
5 SiO2μg/L 15      

4.1.6. Operation parameter requirements of single condensate pump. See table 14-5 for operation parameters of single condensate pump.

Table 14-5 operation parameter requirements of single condensate pump

Operating point of pump Normal operating point Design point Operating point of pump Normal operating point Design point
(guaranteed efficiency point) (guaranteed efficiency point)
Inlet water temperature(℃) appa. 37.9 37.9 Flow ratet/h 1440 1610
Inlet water pressureKPa appa. 0 appa. 0 Pump head (m) 3.3
Inlet water density(kg/m3) 989.12 996 Efficiency (%) 83.3 84.3

4.2. Type selection

4.2.1. Form: vertical, bag type, centrifugal pump.

4.2.2. Layout: vertical arrangement.

4.2.3. Support form: single foundation support.

4.2.4. Blade type: fixed type.

Unit selection (see table 2.4.5)

Table 14-6 selection of equipment body (two units)

No. Name Specification and model   Quantity
1 Pump body NLT500-570×4s Set 4
2 Water pump bearing lubricating water system   Unit 4
3 Cooling water system of motor bearing   Unit 4
4 Matching motor and its accessories (imported SKF Bearing is used for motor rolling bearing and domestic bearing is used for thrust bearing) YLkS630-4, 2000kw, 4P, IP44, F/50Hz, 6KV Unit 4
5 Thermal monitoring instruments (including motor coil, bearing temperature, reversal monitoring, etc.), outgoing line and corresponding junction box.   Unit 4

Note: 1. Water pump: including base and coupling, anchor bolt assembly, pump outlet flange, pump outlet counter flange and its connecting accessories.

2. Motor: including motor base, ventilation grille and filter, space heater, bearing, junction box, grounding device, lifting hook or lifting ring, lifting bolt, resistance temperature detector (RTD) of stator winding, bearing temperature detector and thermal resistance, bimetal thermometer for measuring thrust oil temperature, etc.

3. Water pump mechanical seal cooling water system: including 1 flow orifice plate, 2 check valves, 6 valves and corresponding connection joints.

4. 40 mesh pump inlet filter screen (DN800).

4.2.6. Summary of performance parameters. The performance parameters of NLT500-750 × 4S condensate pump are summarized in table 14-7.

Table 14-7 summary of performance parameters of NLT500-750 × 4S condensate pump

Item Operating point of pump
Normal operation point (guaranteed efficiency point) Designing point
Flowt/h 1440 1610
Headm 352.8 338
Effiency% 83.3 84.3
Required NPSHm 5.3 5.5
Speedr/min 1490
Outlet pressureMPa appa. 3.42 appa. 3.3
Shaft powerKW 1643 1749
Nominal pressure of interface flange Inlet 1.6
MPa Outlet 5
Specification of interface pipe DN (mm) Inlet 800
  Outlet 500
Interface position Inlet Horizontal
Outlet Horizontal
Direction of rotation CCW (from motor end to water pump end)

4.2.7. Structure size / configuration (see table 14-8).

Table 14-8 structure size / configuration

No. Structure / configuration name Size / configuration
1 Outer cylinder size (length × diameter) (m × m) 8.05×1.3
2 Length of pump shaft / number of shaft sections (m/piece) appa. 10/3
3 Impeller diameter (max / min) (mm / mm) 536/500
4 Number of impeller stages 4 stages
5 Type / diameter of first stage impeller (mm) double suction/536
6 Bearing type / quantity Water guide bearing / 3; thrust bearing / 1
7 Rated load thrust / maximum thrust (kN / kN) 34/57
8 Transmission power of coupling (kW) 2000
9 Sealing form Mechanical seal
10 Sealing cooling water volume (t/h) 0.30.6
11 Total weight of the pump (empty/full water) (t/t) appa. 14/26
12 Maximum length of lifting (m) 9.9
13 Maximum lifting weight (T) 10.5

4.2.8. Material of main parts (see table 14-9).

Table 14-9 material of main parts

No. Parts Material No. Parts Material
1 Water inlet horn QT500-7 9 Pump seat Q235A
2 Guide vane housing 10 Motor frame
3 Pump body seal ring 11 Outer cylinder
4 Double suction volute body QT500-7 12 Straight pipe 20
5 First stage impeller CA-6NM(ASTM  A743) 13 Shaft 40CrNiMo
6 impeller ZG15Cr12 14 Coupling sleeve 14Cr17Ni2
7 Water outlet shell Q235A 15 Guide bearing AC-3
8 Reducing shell 20      

4.2.9. Motor parameters (see table 14-10).

Table 14-10 motor parameters

Item Data
Model YLKS630-4
Rated powerKW 2000
Rated voltageKV 6
Speedr/min 1500
FrequencyHz 50
Main characteristic Efficiency% 95
Power factor 0.915
Locked torque (times) 0.8
Locked rotor current (times) 6
Max. torquetimes 1.8
Insulation F
Weightkg 9800
Cooling type Air cooling - water cooling
Rotating direction Clockwise (from water pump end to motor end)

4.2.10. Spare parts:

4.2.10.1. Random spare parts. See table 14-11 for random spare parts of each unit.

Table 14-11 random spare parts (for each unit)

No. Name Specification and model Quantity (unit) Service life (years)
1 All sealing rings and gaskets   2 5
2 Mechanical seal 021-M43K/125-00 1 3

4.2.10.2. Recommended spare parts. The recommended spare parts not included in the total price of each unit are shown in table 14-12.

Table 14-12 recommended spare parts (for each unit, not included in the total price)

No. Name Specification and model Quantity (unit) Service life (years)
1 Guide bearing sleeve   1 5
2 Mechanical seal 021-M43K/125-00 1 3
3 All sealing rings and gaskets   1 5
4 Radial guide bearing   1 5

4.2.11. Special tools. No special tools are required.

4.2.12. Summary of supporting auxiliary equipment. The auxiliary equipment of the two units is summarized in table 14-13.

Table 14-13 summary of supporting auxiliary equipment (two units)

No. Name Specification and model Quantity (unit) Remark
1 Valves and fittings     See scope of supply for details
2 Matching motor YKLS630-4, 2000KW, 6KV, IP44, F 4  
3 Pump inlet screen   4  

4.2.13. Performance curve. The performance curve of the selected pump is shown in Figure 14-15

4.2.14. Appearance. The shape of the selected pump is shown in Figure 14-16

4.3. Typical matching of pump and unit capacity

4.3.1. 300MW unit; 2x50% capacity, 3 sets of NLT300-400 condensate pumps (2 for use and 1 for standby); 1 x 100% capacity, 2 sets of NLT350-400 condensate (1 for use and 1 for standby)

4.3.2. 600MW unit: 2x50% capacity, 3 sets of NLT350-400 condensate pumps (2 for use and 1 for standby), 1 × 100% capacity expansion, and 2 sets of NLT500-570 condensate pumps (1 for use and 1 for standby)

4.3.3. 1000MW unit; 2x50% capacity, 3 sets of NLT400-500 condensate pumps (2 for use and 1 for standby); 1 x 100% capacity, 2 sets of NLT500-600 condensate pumps (1 for use and 1 for standby).

 

5. Scope of supply and general technical specifications

5.1. Scope of supply, termination point and non supply scope (increase or decrease according to customer demand)

5.1.1. Scope of supply of equipment, accessories and instruments:

5.1.1.1 condensate pump body (including outer cylinder)

5.1.1.2. Pump base, anchor bolt, leveling pad and other connecting accessories.

5.1.1.3. Cooling and sealing water pipes, throttling devices and accessories.

5.1.1.4. Coupling and shield.

5.1.1.5. Counter flange and connecting accessories of pump inlet and outlet.

5.1.1.6. Matching motor and accessories

5.1.1.7. Motor TA box

5.1.1.8. Motor heater

5.1.1.9. Pump unit temperature measuring instrument (pump bearing temperature, motor stator winding and motor cooling water temperature measurement).

5.1.1.10. Pump set pressure measuring instrument (pump inlet and outlet pressure, seal water pressure measurement).

5.1.2. Supply scope of spare parts for each product:

5.1.2.1. Pump guide bearing

5.1.2.2. Guide bearing sleeve

5.1.2.3. All pump sealing rings and gaskets.

5.1.2.4. Mechanical seal.

5.1.2.5. Thrust pad for pump.

5.1.2.6. Motor temperature measuring elements (different specifications and models).

5.1.3. Termination point of supply scope:

5.1.3.1. Pump seat of water pump.

5.1.3.2. Embedded parts and anchor bolts of pump unit

5.1.3.3. Inlet and outlet flange of water pump,

5.1.3.4. Water pump seal and bearing cooling water interface

5.1.3.5. Motor cooling water interface.

5.1.3.6. Junction box of motor and heater

5.1.4. Non supply scope:

5.1.4.1. Connected power cables. .

5.1.4.2. Lubricating oil

5.1.4.3. General installation tools

5.1.4.4. General lifting tools

5.1.4.5. Top embedded reinforcement

5.2. General technical specifications

5.2.1. Performance requirements of water pump:

5.2.1.1. The hydraulic performance acceptance test method of the pump shall be carried out according to the provisions of GB / T3216-2005 (or ISO9906) hydraulic performance acceptance test for rotary power pump, and the acceptance level is level 2

5.2.1.2. The performance curve (Q-H curve) of condensate pump flow and head shall change gently, and the head increase value from rated flow (normal operation point) to zero flow shall not exceed 20% of the head at rated flow

5.2.1.3. The minimum flow rate of the pump shall not exceed 25% of the rated flow

5.2.1.4. When the pumps of the same model operate in parallel, the load distribution deviation of each pump is limited within 5% within the operation range of the pump

5.2.1.5. The vibration measurement and evaluation method of pump shall be implemented according to JB / T 8097 "vibration measurement and evaluation method of pump", and its vibration intensity shall comply with the provisions of level C in JB / T 8097.

The noise level of the pump should be evaluated according to the method specified in T806.2 and the measurement method of pump speed.

5.2.1.7. Under various working conditions, the condensate pump shall not be damaged by cavitation.

5.2.1.8. The service life of condensate pump shall not be less than 30 years (excluding vulnerable parts) under the condition that the allowable operating conditions are not exceeded. The service life of condensate pump and its accessories must consider the comprehensive influence of various working conditions during the service life of the equipment. The mechanical seal can operate continuously for more than 8000h. The overhaul period of pump unit is 5 years, and the minor repair period is 1 year

5.2.2. Structural requirements / system configuration requirements of water pump:

5.2.2.1. The equipment and its supporting components shall be designed according to the lateral seismic force

5.2.2.2. The anchorage points of the main structural system can maintain the structural integrity when subjected to seismic load

5.2.2.3. The axial thrust of the pump is borne by the thrust bearing of the pump.

5.2.2.4. All parts of pump set are interchangeable

5.2.2.5. The force and moment generated by the pump body under various conditions (including the closing head) will be borne by the pump body and transmitted to the pump foundation through the support, including the force and moment caused by earthquake and temperature

5.2.2.6. The force and moment of the pipe outside the water outlet flange of the water pump will not be transmitted to the pump unit

5.3. Technical requirements for water pump components:

5.3.1. Impeller. The impeller is made of integral casting, which has enough rigidity and anti fatigue strength to ensure that there is no crack, fracture or harmful deformation under periodic variable load. At the same time, the impeller is made of materials with good cavitation resistance and wear resistance, and has good weldability at room temperature

After the impeller is processed, the static balance test shall be conducted in the manufacturer according to GB / T9239.1-2006 (or iso1940-1:2003) mechanical vibration constant state (rigid) rotor balance quality requirements Part 1, specification and balance tolerance inspection ", and the balance grade shall not be lower than G6.3 specified in the standard. The rotor and its main rotating parts of the pump are tested in dynamic balance, and the accuracy is not lower than grade G2.5 specified in the standard

5.3.2. Pump shaft. The pump shaft is made of high quality alloy steel or stainless steel. It has enough strength and rigidity, and can bear torque, axial force and radial force under any working condition

The sectional position and quantity of the pump shaft can facilitate the disassembly and assembly of the pump unit and the arrangement of the guide bearing. Each sectional shaft is connected by a coupling. The form of the coupling can facilitate the disassembly and assembly of the pump unit and ensure the safe and reliable operation of the pump unit, and ensure the concentricity and straightness of the shaft

The pump shaft and coupling are connected by standardized key and keyway

The supplier is responsible for coordinating the connection between the pump shaft and the motor shaft, the design and manufacture of the shaft system and the calculation of the critical speed of the pump shaft; the first critical speed of the pump rotor is 125% higher than the working speed, and the pump shaft should be operated within the maximum speed range without harmful deformation. The size of the center hole used for machining the pump shaft can be easily processed and tested, and the screw hole for lifting is set at the end of the shaft; The surface roughness of the pump shaft for assembling shaft sleeve and coupling shall not be less than 1.6 μm, and the circular runout shall not be lower than Grade 8 specified in GB / T 1184-1996 (or ISO 2768-2:1989) shape and position tolerance: undeclared common threshold value

5.3.3. Guide bearing. The guide bearing is made of AC-3 composite material. It has the advantages of good wear resistance, stable size, small thermal expansion coefficient and water swelling property in the operation of condensate medium. The service life of the bearing is more than 10 000 h. The guide bearing does not need external lubricating water, but adopts the pumped medium self lubrication. The structure of the guide bearing should be easy to replace the bearing

5.3.4. Thrust bearing, the pump thrust bearing is set on the pump outlet shell, mainly bearing the rotor mass of the pump and the axial force generated by hydraulic under various working conditions. The thrust bearing adopts the form of plane sliding thrust pad and adjustable sliding guide pad, adopts oil bath lubrication bearing box, does not need forced lubrication, adopts cooling coil or external cooling water of water chamber for cooling; in addition, it is also equipped with oil level gauge, Pt temperature detection head of pad, exhaust port and oil filling port

5.3.5. Main shaft seal. In order to meet the requirement of good sealing, packing seal or floating seal are usually used

Pump housing parts. The pump shell components are mainly composed of inlet horn, double suction volute body, guide vane body, straight pipe and outlet shell, which are connected by stainless steel fastener flange. The inlet horn shall be of cast structure, and its shape and size shall ensure good hydraulic characteristics; the double suction volute body and guide vane body shall be integrally cast, and the flow passage part shall be guaranteed to have good hydraulic performance to avoid vibration caused by vortex belt excitation; the straight pipe shall be welded with reinforcing rib and connected in sections; A degassing port is set on the upper part of the outlet shell, which can be connected with the condenser to discharge the gas in the pump to the condenser in time

5.3.7. Foundation components. The foundation components include pump foundation plate, anchor bolt and connecting bolt. The structure of metal surface and sealing ring is used between the pump foundation plate and the outer cylinder, which is required to be sealed tightly without water leakage; the contact surface of all parts, including the contact surface between the pump foundation plate and the outer cylinder, shall be machined surface and meet the requirements of appropriate roughness; the pump foundation plate shall be of casting or welding structure.

5.3.8. Outer cylinder. The outer cylinder shall be of welded structure with guide bars at its bottom; the shape shall ensure good hydraulic performance, no harmful whirlpool, small hydraulic loss, and uniform water flow into the inlet horn shape of the pump. The outer cylinder adopts vacuum design.

5.4. Performance requirements of supporting motor:

5.4.1. The design of the motor shall be consistent with the operation conditions and maintenance requirements of the water pump, and the characteristic curve (especially the load characteristic curve) of the motor shall fully meet the requirements of the water pump.

5.4.2. The output of motor name plate shall not be less than 115% of the driving equipment.

5.4.3. The service life of motor (excluding wearing parts) shall not be less than 30 years, the overhaul period of pump unit shall be 5 years, and the minor repair period shall be 1 year

5.4.4. The motor shall have insulation of class F and above, the temperature rise shall not exceed the temperature rise value of class B insulation, and the motor winding shall be subjected to vacuum impregnation treatment (VPI)

5.4.5. The motor is asynchronous motor. At the same time, the variation of rated voltage and frequency is within 10% of the rated frequency range.

5.4.6. Under rated voltage, the multiple of starting current of motor shall not be greater than 6.0

5.4.7. The motor is of direct starting type and can be started successfully according to the load shown in the speed torque curve of the driven equipment. When the power supply voltage is reduced to 70% of the rated voltage, the motor can start automatically.

5.4.8. The motor shall be started no less than 2 times in cold state, and the cycle period of each start shall not be more than 5 min; the motor shall be started at least once in hot state. If the starting time is less than 2 ~ 3 s, the motor can be started once more

5.4.9. The vibration measurement and evaluation method of motor shall be in accordance with the provisions of GB10068 measurement, evaluation and limit value of mechanical vibration of motors with shaft center quotient of 56mm and above, and its vibration intensity shall comply with the provisions of grade n in GB10068.

5.4.10. The noise measurement and evaluation method of motor shall comply with the provisions of GB / T10069.1-2006 determination methods and limits of noise emitted by rotating electrical machines - Part 1: methods for determination of noise emitted by rotating electrical machines (GB / T10069.1-2006), and the noise shall comply with the provisions of GB / T10069.3-2008 measurement methods and limits of noise emitted by rotating electrical machines - Part 3: noise limits.

5.4.11. When 1/4 of the water cooler is damaged, the motor can still output rated power and ensure that the temperature rise of each part does not exceed the maximum allowable temperature rise.

5.4.12. The temperature of motor rolling bearing shall not exceed 90 ℃, the temperature of sliding bearing shall not exceed 80 ℃, and the oil temperature shall not exceed 65 ℃

There shall be clear signs of direction and rotation of the motor,

5.4.14. The phase sequence of motor shall be marked in the junction box.

5.5. Structural requirements / system configuration requirements of supporting motor:

5.5.1. The overall dimension and installation dimension of the motor shall meet the requirements of the water pump supplied.

5.5.2. The motor is installed vertically, and air + water or air + air cooling mode can be adopted.

5.5.3. The motor rotor is of squirrel cage structure, and reliable measures shall be taken to prevent broken bars of squirrel cage.

5.5.4. Magnetic slot wedge is not used for motor stator slot wedge,

5.5.5. The air gap unevenness of the motor shall not be greater than the specified value in table 14-14.

Table 14-14 requirements for air gap unevenness of motor

δ(mm) 0.8 0.9 1 1.2 >1.4
ε/δ(%) 17.5 16 15 13 10

5.5.6. The motor bearing shall be made of high-quality and wear-resistant products, and the structure shall be sealed to prevent lubricating oil from penetrating into the winding. Oil peeping window shall be set to monitor the lubricating oil return of bearing oil.

5.5.7. The motor shall be provided with 6 wiring jumpers, and the connector for internal wiring and external cable connection shall be provided.

5.5.8. The protection grade of motor is IP44.

5.5.9. The motor shall be equipped with reliable grounding device and obvious signs indicating grounding.

5.5.10. Heater shall be set to prevent internal moisture and condensation when the motor is out of service; the heater shall be installed at the position inside the motor which is easy to see.

5.5.11. Neutral point TA outlet box shall be set for motor,

5.5.12. The motor shall adopt standardized components and equipment components.

5.5.13. PT100 double three wire or four wire thermal resistance temperature measuring elements shall be embedded in the local hottest part of the motor stator winding, 2 for each phase and 6 for each set. The temperature measuring elements shall be evenly distributed and embedded between the upper and lower bars in the stator winding slot.

5.5.14. The temperature measuring element of motor bearing adopts double K-index armored thermocouple, and one upper and one lower guide bearing are respectively installed,

5.5.15. The thermocouple installed on the motor bearing shall be compressed by spring, and the spring must be supported on the bearing shell with sufficient strength.

5.5.16. Double k-division armored thermocouple temperature measuring elements shall be embedded at the air inlet and outlet and water inlet and outlet of motor cooler.

5.5.17. Special temperature measuring element lead-in terminal box shall be installed at appropriate position outside the motor base.

5.6. Instrumentation and control requirements:

5.6.1. The pump manufacturer is responsible for designing and providing the instruments, control devices and test interfaces for the operation monitoring of the pump set, as well as the alarm, interlock and protection control conditions of the pump set.

5.6.2. The local instruments and detection elements provided with the pump unit shall meet the national or international standards, with the same specifications and models, and the selection of measuring elements shall meet the requirements of the control system.

5.6.3. For instruments and control equipment within the scope of supply, KKS number, model and specification, installation location, application and manufacturer shall be specified.

5.6.4. The accuracy of the local indicating instrument is generally 1.0, and the diameter of the panel is not less than 100mm. The range of the meter should be selected so that the pointer is at the position of 3/4 range during normal operation.

5.6.5. The general requirements for measuring points and instruments include but are not limited to PT100 thermal resistance for motor stator winding and bearing temperature measurement, and PT100 thermal resistance for motor cooling water temperature measurement.