submersible sewage pump
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One Mistake of Centrifugal Pump Selection
When high head water pump used for low head condition, many user think the pump pressure is lower, the electric motor load will be less. With this wrong consideration, when they purchase water pump, they usually select a very high pressure pump.
Actually for centrifugal water pump, when confirm pump model, the power consumption proportional to pump real flow rate. But the flow rate will reduce with an increase of pressure(head), so the pressure is higher, the flow rate will be smaller, the power consumption will be less. Otherwise, lower head, bigger flow rate, the power consumption will be more. So to prevent motor overload, general request is pump actual pumping pressure shouldn’t low than 60% of design head. If for emergency application, the outlet pipe must be installed with a gate valve(adjust flow rate), to reduce flow rate, prevent motor overload.
Notice the electric motor temperature, if you found motor overheating, we should reduce pump outlet flow rate or close the pump.
This point is also easy make misleading, some people think block pump outlet, force to reduce flow rate, the electric motor load will be increased. In fact, just the opposite, there is gate valve installed on formal produced large power centrifugal pump, in order to reduce motor load when start up, we should close the gate valve first, when electric motor start up, then open the gate valve gradually.

submersible sewage pump


Tips for Pump Installation

Please take note as below when install the pump:
1. The preformed hole on the foundation should be poured as the pump installation drawing.
2. The installation level should meet the demand of the allowed vacuum suction height. The foundation should be in horizontal and stable condition, to make sure the rotation of the driver machinery same with the pump in the direction.
3. When connect by coupling, must make sure the pump and driver shaft center  should be in a straight line.
4. If belt connection, the shaft center should be in parallel.
5. The pump suction pipe should be sealed well, and try to less the quantity of the elbow and check valve. When fill water, exhausted the air. It should be no any air when operate. We need to keep the suction pipe slopes up slightly, and then connect with the pump inlet.

submersible sewage pump


Pump Type Classification
1.classify by impeller numbers: single stage pump and multistage pump;
2.Classify by pump shaft and horizontal level position: horizontal pump and vertical pump;
3.Classify by suction method: single suction pump and double suction pump;
4.Classify by pump body split type: radially split pump and  axially split pump;
5.Classify by driving type: coupling driving, belt driving, gear driving, hydraulic coupling driving, coaxial driving type.

Froth Pump Brief Introduction

Pump head of froth pump is double volute pump structure,The wetted parts use hard nickel high chrome alloy,Part of driven is the same as sump pump.funnel charging box is steel plate structure,According to type of transporting medium, Outlet position of pump can change in every 45°this pump can eliminate the froth of pump in running effectively.Under the lack of feeding materials condition.this pump still can work well.

Applied arrange: It is the best choice for transporting medium like foam-like slurries in all kinds of flotation process. Transporting ability is far more than other pumps.and this pump don’t need to add shaft sealing and shaft seal water.

Capacity:7-580m3/h
Head:5-30m
Outlet diameter:50-200mm
submersible sewage pump

The Influence of the Flow and Slurry Pump Size Choosing
     The most direct result of the smaller flow reduces can make the efficiency of slurry pump  smaller and make the motor power increases. General speaking, Centrifugal pumps are designed by the point which located in the highest point of the Efficiency curve. If the centrifugal pump operating point in the low flow operation point, its operational efficiency will drop quickly, under normal circumstances, the same pump flow rate is smaller, the efficiency of the pump is smaller, so it is not full useful if run in low flow conditions. Under normal circumstances, you need choose the new high efficient small slurry pump again this times to suit the low flow or head.

submersible sewage pump

Characteristic of Submersible Sewage Pump
Adopting special single vane or double vane impeller structure, which improve the sewage through capacity greatly, and can effectively through fiber material 5 times of pump diameter and solids diameter 50% of the pump.
The submersible sewage pump adopts new type hard corrosion resistant tungsten carbide or silicon carbide material, at the same time improves the sealing to double end seal, which makes it running in the oil chamber make sure the pump can operate continuously for more than 8000 hours.
The submersible sewage pump structure compact, small volume,low noise,energy saving effect remarkable, easy maintenance, no need pump room, it can work submerged in water, dramatically reduce the project cost.
The submersible sewage pump closed oil chamber internally installed high precision anti-interference leakage detection sensor, and thermal sensor installed in the stator winding, which prevent damage due to pump motor overheating or overload.


 Pump’s Pipeline Configuration Considerations
The size of the pipe diameter’s choose need to consider the system resistance, slurry flow rate and other comprehensive settlement of the critical factors. Suction pipe should be short and straight. In the suction of the pump, the best way is install a straight pipe what have some size with the inlet pipe’s diameter, its length should not be less than three times of the inlet diameter. Generally speaking,the suction pipe flow is 1.5-3.0m / s, depending on the flow rate of the slurry.
When using high pump suction piping’s arrangement should avoid the residual air, recommend adopt the level reducer pipe.
The control valve should be located in the pump outlet pipe when use the flow control valves,it is not be allowed install in the inlet pipe, in order to avoid cavitation.

Submersible Sewage Pump Application:
Submersible sewage pump used for all kinds of drainage system. Such as enterprise wastewater discharge, Urban sewage treatment plant system, Subway, basement, civil air defense system drainage station, Hospital, hotel, high-rise building sewage discharge, Residential sewage drainage station, Municipal engineering, Thin mud discharge in construction site, Supply water equipment for Waterworks, Farm Sewage discharge and farmland irrigation. Pumping water in mining and water level control

Submersible Sewage Pump Selection
Submersible sewage pump can match the totally automatic safe protect control cabinet, which can protect or avoid the water leakage, electricity leakage, overload, or over heat absolutely. This can improve the security and reliability.
Float switch can control the pump start and off according the liquid level. It convenient the installation and maintenance. Then the worker do not need to connect the waste water.
Submersible sewage pump can work on the full head and ensure the motor not overload. It have two different ways to install: auto-coupled installation and movable free installation systems.


Pump Performance Curve
Generally a graph showing the relationship between the main performance parameters called centrifugal pump performance curve, actually the centrifugal pump performance curve is external manifestations of liquid movement in pump, obtained by test.
Pump performance curve include: flow-head curve(Q-H), flow-efficiency curve(Q-η), flow-power curve(Q-P), flow- NPSHr curve(Q-(NPSH)r), performance curve function is any point of flow, could be found it’s head opposite thereto head point, power point, eff point, and NPSHr on the performance curve, the parameters we call it working condition, or working point. Centrifugal pump highest eff point is called optimum operating point, and general the optimum operating point is design point.
General centrifugal pump rated parameters (its design point) is overlap or very approximative to optimum operating point. When select pump, we consider both energy-efficient, and ensure normal operation of the pump, so it’s very important to know the performance parameters of the pump.



Classification of the Impeller
1.Classify by sution way :
1)Single suction impeller (Impeller suction from one side)
2)Double suction impeller(Impeller suction from two side)
2.Classify by cover plate:
1)Closed impeller
2)Open impeller
3)Semi-open impeller
The closed impeller is more popular. Usually,Used impellers are closed impeller.


The Centrifugal pump Cavitation Phenomenon
Centrifugal pump cavitation phenomenon is due to the liquid to be delivered in transporting temperature saturated vapor pressure is equal to or below the pressure at the entrance of pump blade and partial vaporization. Vaporization produces steam, form bubbles. The bubbles move forward step by step, as the liquid reaches a certain height, the bubbles sharply shrink and burst out. Liquid particle filling holes at high speed, and have a strong impact on the metal surface which makes it peel off, and cause the pump noise and vibration, when serious, the capacity, head and efficiency of the pump reduce significantly. The centrifugal pump cavitation phenomenon is not allowed to happen under normal operation. The key to avoid cavitation phenomenon is the installation height of the pump should be correct, especially should pay more attention when conveying high temperature and easy volatile liquid.

Centrifugal Pump Power Loss
There only a part of the mechanical power of the centrifugal pump getting from the driver equipment, convert to the centrifugal power and then delivered to the liquid power. The another part was loss. The reasons are below:
1. Hydraulic loss: Created for the liquid impact, vortex and friction in the pump. The impact and vortex hydraulic loss is because of the the liquid change the flow direction. Besides, when the liquid flow, it will have friction when meet the pump passageway.This kind of loss depend on the length, volume, shape, and surface roughness of the passageway and the liquid flow speed and other character.
2. Volume loss: It resulted for the powered liquid will channeling are leakage. The general pump volume efficiency is 0.93~0.98%. Improve the seal ring and shaft seal construction, can reduce the volume loss and increase the volume efficiency.
3. Mechanical loss: It is caused by the friction of liquid and impeller plate surface, also named dick friction loss of impeller, and the pump shaft friction when rotated in the packing, bearing, balancing parts and other mechanical parts. 


Slurry Pump Inlet and Outlet Piping’s Configurations and Requirements
    
Suction pipe diameter: Slurry pump’s Suction pipe diameter should not bigger than the pump inlet, in principle, both to avoid pump’s cavitation, and not to make the slurry sinking in the pipeline.
Suction valve: for ease to maintenance the pump, suction valve should be add in the pump. This valve’s diameter should be same with suction pipe’s diameter. The expansion joints should be install between the inlet and the suction pipe ,so that the pump candestuffing conveniently.
Discharge line diameter: diameter have connect with slurry discharge properties and sedimentation flow rates, in general, the diameter of the discharge outlet and the slurry pump diameter is same or larger slightly.
Outlet valve: the discharge pipeline and the outlet valve should be the same diameter.
Pressure Gauge: Located between on the slurry pump outlet pipe and valve .
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