What should noted when operate Slurry pump?

1. Check the shaft seal water pressure and flow regularly.

For the Expeller + Gland seal, must adjust the gland aseembly timely and replace new gland regularly, to ensure little clean water to the shaft invariably.
For the mechanical seal slurry pump, it not allowed operate without shaft seal water nor seal water pressure insufficient.

2. Check the base conditions regularly, together check the cleaness of lubricating oil and the oil volume. In order to avoid the bearing overheat, can add the cooling water if necessary.

The slurry pump market in South Africa

South Africa, officially the Republic of South Africa, is the southernmost country in Africa. The discovery of diamonds in 1867 and gold in 1884 in the interior started the Mineral Revolution and increased economic growth and immigration. Until now, the South Africa still one of the most important country in mine market. The slurry pumps are also the major market of slurry pumps with the developing of the mine industry of South Africa.

Slurry pump is the centrifugal pump moving slurry, continuous pumping of highly abrasive/dense slurries in processes from cyclone feed to regrind, mill discharge, flotation, mine drainage, dredging of settling lagoons and pumping of drilling mud and tailings in minerals plants plus other industrial applications.

Shijiazhuang An Pump Machinery Co., Ltd, is one professional manufacturer in slurry pump and we send many slurry pumps to South Africa as well. As one of the best manufacturer in pumps of China, We have flexible policy in foreign trade and credit support. We have special discount policy and promotion roles for our agent all over the world. You are welcome to be our agent and pls feel free to contact pump@angroupcn.com to let us discuss more!!!

Click to know more about the slurry pump!

Four methods to improve the energy efficiency for the slurry pump

Four methods

improve the energy efficiency 

for the slurry pump

As we all know, the slurry pump is an essential mineral processing equipment industry, its main role is to provide the impetus for pipeline transportation.

Slurry pumps from the use of unreasonable or blind method of choice, leading to the slurry pump energy waste, excessive wear and other issues.

Here ANPUMP technician simple explanation reasonable for the slurry pump using in several methods:

1. In accordance with the type of ore reasonable choice liner materials.
2. In accordance with the actual needs of the flow and head selection. Maybe bigger but lower speed of the slurry pumps are the best solution.
3. The motor and slurry pump power must be matched reasonable
4. The scientific and rational installation

The above four is safe for your slurry pumps selection and operation, as long as the rational use of these methods concentration, the concentrations will be able to improve their productivity, to achieve energy efficiency goals for the slurry pumps.

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More features of the BP/BPR series heavy duty cantilever sump pump

The BP(R) series heavy duty cantilever sump slurry pump are designed for the fuild in the sump or pit when the normal waste vertical pump not handling, it is the vertical centrifugal slurry pump for the abrasive and corrosive slurry transporting. It is the single stage, double suction, cantilever heavy duty pump. It dont need the shaft seal and no submerged bearings. The hard metal and elastomer parts (rubber parts)are optional for different applications and interchangeable, which make the BP(R) series vertical centrifugal slurry pumps to be suitable mos conditions where you need pump the slurry pump from the pit or sump.

 BP/BPR series heavy duty cantilever sump pump

The BP(R) series heavy duty cantilever sump slurry pump are especially suited for sumps and pits where wash down from all over the plant collects for removal.

1) The BP(R) series heavy duty cantilever sump slurry pumps are the cantilever sump slurry pump without shaft seal and no bearing under the fluid. The top and bottom suction draws slurry away from bearings. The anti-abrasvie high chrome white cast iron and rubber  wet end parts design make it could handle the abrasive and corrosive slurry with chemcial like gold mine processing.

2) The agitator are optional to keep the solid without settlement.

3) The double suction design with high capacity, lower speed rotating, easily replaceable elastomer or white iron liners and impellers make the BP(R) series heavy duty cantilever sump slurry pumps are easy to main, minium the downtime when standby pumps are not available. The top and bottom suction allows for

greater flow access and reduces material "coning" around the standard bottom-only vertical pump intakes.

4) The length of the shaft are from 300mm to 3600mm for different size are widely match different customer's pit or sump required. There is SUCTION

EXTENSION for pumping out deep-set pits and sumps more!

Widely Fielded Applications

●Mining & Mineral Processing ●Flue Gas Desulfurization desulfurization ● Coal Washing ● Building Materials

Tailing

Cabron In Leach(CIL) Gold

Floor Pumps

Cool Preparation

Mineral Processing

Industrial Sand and Aggregate

Chemical Processing

I All life cycle cost of your pump project management

I believe that to be the manager of the mine, you should take the cost of your mine in your mind every minutes. However,

"Do you ever try to consider how to control the cost to make your work better?"

"Yes, of course, I am professional and I always try to control it!!!BUT I AM NOT PROFESSIONAL AT PUMPS, GOD KNOWS WHY WE NEED BUY SO MANY SPARE PARTS FOR OUR SLURRY PUMPS!!!"

Yes, "WHY YOU NEED SO MUCH SLURRY PUMPS PARTS?" It is really big questions including so many details even your manufacturer or engineers professional at pumps, they could list all facts that you need buy the pumps but I am sure the first sight in your mind when the table in your eyes, "Damned, it is nothing only ask me want to buy more from them..."

So, no problem, to answer why you need buy so many pump parts, let us tell you something you might not realize:

What is the total life cycle cost of your pump project or pump system?

In usual, there are six field:

1) Purchase and Installation

It is easy to understand, however, the buyer or procurement always not pay attention to the important of necessary spare parts purchasing and the importance of worker knowledge. The worker should be experienced in pump install to avoid extra cost, they should know how to install the pumps especially about the shaft seal and sometimes, the worker would be "careless" to forget installing of the joint ring. Of course, it is more important that the buyer should buy the necessary shaft seal extra and intake/discharge joint ring and emphasize the manufacturer should ship them together.

If it possible, the buyer should be at site when the pumps they buy installing then they should know what they should do in next procurement. They only realize the important of the pump quality and the details like the shaft of the engine&pump should be in same line level.The taper type sheaves are expansive but the worker will tell you it is really easy to use than normal type. More pls check II All life cycle cost of your pump project management tommorrow!

PS. Look, my friend, it is not me but your worker tells that some parts are necessary :) However,if I am the buyer, I should ask the manufacturer send the necessary spare parts be free ^_^ If you buy from me, it is never mind to send some small parts be free but mechanical seal...hmmm...let us should check the pump and sales amount first, do you believe that some small parts like the bearing and mechanical seal, it is important rating of the pump cost!

ANYHOW, CONSIDER SOME NECESSARY COST IS THE KEY TO AVOID MORE LOST!

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The Feature of the slurry pump

Slurry Pump	Slurry pump is the centrifugal pump moving slurry.
How to select the pump	First, we should know what fluid could be pumped:
	Gas	We take air as the gas.
	Liquid	The water is the most popular liquid, here we take the water or the thing similar water as the liquid.
	Slurry	The mixture of liquid and solids particles
When you need Slurry Pump	• To pump a medium where abrasive particles are present( The medium with few particles or not abrasive, which means the medium similar clear water that you could use clear water pumps, dirty water pumps or mud pumps is good enough) • To transport the productions required or as much solids as possible hydraulically
The Feature of the slurry pump (Why is the slurry pump instead of water pump, mud pumps etc.)	1. The heavy and robust slurry pump and perfect used perfect impeller structure ensure satisfactory performance with long life and needs minimum maintenance requirements. • Extra-Thick Wet End Components make the slurry pump could handle the liquid with abrasive solid particles and extend the wear life • Large diameter, slow turning, high efficiency impellers designed to achieve maximum wear life and low operating costs • Large, open internal passages designed to reduce internal velocities, maximize wear life and lower operating costs More...
	2. New development of the anti abrasive cast iron to enhance efficiency and improve wear performance. • Continuous improvement of High Chrome anti-abrasive cast iron and rubber provide superior corrosion resistance plus reduce overall maintenance costs and maximize wear life More...

What is the slurry pump?

What is Pump?

Pump：A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action.

Type 1

There are two basic types of pumps by operating principles: positive displacement and centrifugal.

Type 2

Fluid pumped: liquid, gas and slurry

What is The Slurry

The slurry can be a mixture of virtually any liquid combined with some solid particles.

The combination of the type, size, shape and quantity of the particles together with the nature of the transporting liquid determines the exact characteristics and flow properties of the slurry. The liquid is always the water.

What is The Slurry Pump

Slurry Pump is the centrifugal pump moving slurry.

Next, The feature of slurry pump,click to know it!

Submersible sewage pump impeller structural features

Submersible Pump Impeller

With the development of science and technology, pumping solid materials growing application areas, such as sewage dirt, mud pulp, ash, grain starch, sugar beet fruit, fish and shrimp shells, and so on. Pump for delivery of such substances has two main requirements: First, no plug, the second is resistant to wear. Wear-resistant materials primarily related to non-clogging impeller depends mainly on structural forms.

Currently as a non-clogging sewage pump impeller main structure are: 1 single (double) flow impeller; 2 swirl impeller; 3 open or semi-open impeller; 4 screw centrifugal impeller.These types of non-clogging impeller have their own characteristics and suitable for different occasion, as compared as follows:

Single flow impeller - for good lossless transport of materials, non-clogging and good performance, suitable for transporting large particles long fiber material, and good wear resistance, but to balance the requirements of high, running balance is poor.

Double channel impeller - Capacity slightly worse than a single runner, but as symmetrical runner, it has a good balance of performance, smooth operation and suitable for high head, high flow pump.

Swirl impeller - Good non-clogging performance, wear resistance, suitable for handling large particulate matter, but lossless, poor delivery of materials damaging effects of large,  it can transport liquid containing gas but not suitable for transporting liquid containing long fiber material.

Open or semi-open impeller - such as wear gap increases, pump performance degradation, poor performance and non-blocking, it can not transport large particles and long fiber material.

Screw centrifugal impeller - without clogging good, suitable for liquids containing particles and fibrous matter, small-destructive and non-destructive that is good no-wear, but require a higher balance.

Centrifugal Pumps Self Priming Failure Analysis

Centrifugal pumps with its simple structure, easy maintenance and high efficiency become one of the most widely used agricultural pumps, but also because sometimes lift no water and people feel more trouble. Now let’s to see why lift no water.
1) Some users are not filled enough water before starting the pump ; sometimes it looks irrigation water from the bleed hole overflow, but the rotation shaft will be fully discharged air, causing a little air still remains in the inlet pipe or pump .
2) Pump packing worn by long-term use or filler weight too loose, resulting in a lot of water ejected from the gap filler and shaft sleeve, the result is the outside air enters the pump  inside from these gaps,effect lifting water.
3) Inlet pipe is always underwater for long time.Pipe wall corrosion occurs.The water level is declining after pump work,when these holes out of the water, the air entering the inlet pipe from the hole.
4) The inlet pipe bends cracks appeared, slight gap between inlet pipe and pump connections appeared, are likely to allow air to enter into the water.

Pls contact roger@angroupcn.com if you are interested to know more!

More shipment review, pls click

How to test centrifugal pump?

Generally, there is two method to test centrifugal pump, type test and factory test.

The centrifugal pump test ─ Type Testing

Includes: running test, performance test and cavitation test and noise vibration test, etc.

(1) Running test

When running test, should check the rise of temperature of the pump bearing and packing, leakage of pump packing in vibration and noise.

(2) Performance test

Performance test is to determine the lift of pump, shaft power, the relationship between the efficiency and flow rate. Centrifugal pump starts from zero flow (at least) is greater than the measured using range is 15% of the maximum flow; Mixed flow pump, axial flow pump and vortex pump starting valve fully open, at least to 15% less than the minimum flow rate measurement. Measuring point should be uniform on the whole curve of centrifugal pump and vortex pump more than 13 points, axial flow pump, mixed-flow pump more than 15 points.

(3) Cavitation test

Cavitation test used to determine the relationship between the critical cavitation allowance and flow.Or used to verify the critical cavitation allowance is less than or equal to the provisions of the pump of the necessary cavitation allowance.

The centrifugal pump test ─ Factory Test

Factory test is used to check whether the performance of a centrifugal pump is suitable before they leave the factory. Factory test of centrifugal pump only commonly work within the scope of the small flow points, traffic, large flow points more than three flow to test and check the pump head and power.

Why is the pump suction pipe often one size bigger than the pump connection?

It has become common practice to always have the pump suction line at least one size greater than the pump suction flange size. The transition is accomplished with an eccentric reducer usually with the flat on top but not always. The most critical thing about the pump suction is to ensure that the flow stream lines arrive at the suction eye of the pump with no large scale turbulence as can be caused by an upstream elbow. This is a function of the pipe geometry which means that a nice long straight suction pipe is desirable. A larger pipe reduces the pressure drop due to friction and provides more pressure at the pump eye, this provides more energy to the pump.

All kinds of cockamamie pump suctions have been designed in the past for various reasons and some of them even work. However, as a piping designer you don't want to re-invent the wheel all the time and you are looking for tried and true methods that will let you sleep easy.

What is centrifugal pump’s NPSHr?

Do you know What is centrifugal pump’s NPSHr?

One common mistake pump novices sometimes make is to overlook a little detail called Net Positive Suction Head (NPSH) when making a pump selection. When considering pump selections the first thing most people are taught is to look for is a selection with high-efficiency, and one where the design condition falls close to the best efficiency point. When operating under an overwhelming mountain of new information the pump novice will sometimes forget to make sure the Net Positive Suction Head Required (NPSHr) characteristics of the pump are suitable for the application. While understandable, this mistake can lead to large problems further down the road. While a pump may potentially provide acceptable performance at lower efficiencies and at a point that is not very close to BEP, a pump that is tasked with operating with inadequate Net Positive Suction Head Available (NPSHa) will see a considerable decrease in the head and flow produced and further deterioration in performance due to internal damage can be expected in relatively short order. As a result, ensuring the NPSHr characteristics of the pump are compatible with the NPSHa characteristics of the system is a critical step in the pump selection process.

Pumps Test

10 Ways to Select a Happy Pump

1) Only Select pumps with suction specific speeds less than 11,000- less than 9,000 is even better.
2) Select your pump so it never operates bellows 70 percent to 80 percent of its best efficiency point.
3) Remember that 1800-rpm pumps are usually more reliable than 3600-rpm pumps.
4) Hydraulic efficiency peaks at specific speeds between 2000 and 3000 and drops dramatically below a specific speed of 500. Higher efficiency means less vibration and noise and lower energy bills.

5) Use Double suction impeller sparingly. They are less stable at off-design conditions than single suction impellers.
6) For single stage pumps, never select a pump with a maximum diameter impeller. You may need to increase the impeller diameter in the future.
7) Select a driver that allows you to operate to the end of the pump curve.
8) Use hydraulic stability, not temperature rise, as criteria for setting the minimum acceptable pump flow.
9) Incorporate a healthy NPSH margin or ratio, i.e, NHPSHr/NPSHa into your selection. This ratio should be anywhere from 1.1 to 2.0 depending on the fluid, criticality and suction energy level. A higher value is always better.
10) Consider fluid volatility when making your pump selection. Be more conservative when the fluid has a single boiling point, as opposed to a fluid with a wide boiling point range.

Pump mechanical seal common problems and analysis

Pump mechanical seal, you should use the double-headed welding way.Usually the mechanical seal is mounted on the coupling, which includes shaft sleeve, gland seal rings, drive ring and a series of components. The advantage is relatively easy to install, also it has the disadvantage that you must replace the entire when broken, it will increase costs. An Pump Machinery next to help you to further analysis.

First,A sealing surface damage causes are:

1, Impurities into the sealing surface, resulting in the sealing surface damaged, it can not form a water film.

2, Cavitation. When pump into the water is not enough or too much water yield,it will appear the pump without water absorption, so as to form bubbles, after impeller pressure bubbles volume turn smaller, bubble arrived at the position of mechanical seal, due to the external pressure is reduced, air bubble explosion, and make the mechanical seal face, or rubber ring damage.

3, The medium temperature is too high or too low, resulting in damage to the mechanical seal.

4, Adjust the amount of string too much, too tight mechanical seal, resulting in mechanical seal can not form a water film, static ring dry grinding, resulting in damage to the mechanical seal.

5, Sealing surface stress non-uniform, if after the ring spring action in uneven force on the surface of the ring, it can not form a water film, so that the mechanical seal is damaged. During installation,if the sealing surface adjustment uneven, it will cause uneven stress.

An Pump Machinery pumps, mechanical seal face damage is mainly due to the first and the second,the third case is rare. And fourth, fifth case rarely occurs, because each pump in An Pump will be tested before delivery.

Second, the rubber ring is damaged main reasons:

1, Medium errors, some rubber parts are oil resistant, some rubber parts are alkali resistant, different medium selected seal should also be different.

2, Cavitation. As already mentioned.

An Pump water pump is in very good quality, the fault does not occur under normal circumstances, but the customer must use it properly.

Mechanical End of Centrifugal Pump

The impeller is mounted on a shaft. The shaft is usually made of steel or stainless steel and is sized to support the impeller. Impellers have to be sized carefully. An undersized shaft can result in increased pump vibration, shorter bearing life, the potential for shaft breakage, and an overall reduced pump life.

Generally speaking the pump shaft is covered with a shaft sleeve. The shaft sleeve is a sleeve of metal, usually bronze or stainless steel, that is designed to either slide or thread onto the shaft. The shaft sleeve is used to position the impeller correctly on the shaft, and it also protects the shaft.

In order for the shaft to hold the impeller within the casing it must pass through the casing. The point where the shaft enters the casing is called the stuffing box and must be sealed. The most typical sealing mechanism is the mechanical seal.

Mechanical seals vary tremendously in design, performance, and cost. The simplest seal consists of just a few primary parts: a stationary face, a rotating face, a gland, and a spring. The rotating face is a ring of smooth hard material that is fastened to shaft sleeve, and the stationary face is a second ring of smooth hard material fastened to the casing. The gland bolts to the outside of the casing and the spring is placed under tension between the gland and the stationary seal face causing it to press against the rotating face. As the pump shaft rotates the rotating face will rotate against the stationary face. A small amount of the pumped liquid will make it’s way between the faces keeping them cool and lubricated. As long as the seal faces stay clean, smooth, and lubricated they will virtually eliminate leakage around the shaft.

The final part of the mechanical end is the bearing arrangement. Generally speaking centrifugal pumps are equipped with standard ball-type anti-friction bearings. These are the same bearings used in everything from electric motors, to roller skates, to automobiles, and they are lubricated by grease or oil. The pump shaft is supported and held in place by the bearings which have to be designed to handle all of the loads created by the rotation of the impeller, and sized to provide a reasonable service life. Bearing failures are one of the most common causes of pump downtime so designing Engineers and End-Users will often be particularly interested in the specifics of bearing design, and the pump professional will be well served to spend time learning the ins-and-outs of the bearing systems of the pumps in question.

The disadvantages of the Packing seal for slurry pump

1, It requires the loss of 10% to 15% of the shaft power to overcome the frictional force between the sleeve and the filler to effect a seal.
2, Packing seal contact force comes from the packing gland on axial pressure filler leaving the radial expansion force, resulting in greater friction between the filler and the sleeve, thus it require frequent replacement of worn sleeve.
3, Packing seal leakage is easy to make drain fluid into the bearing housing, causing damage to the bearings.
4, In order to move away the friction between packing and the shaft, it must have quantitative leak, resulting in the loss of cooling water. In short, the advantages of packing seal is simple. The disadvantage is the maintenance workload, power loss is large, and because it is always a certain degree of leakage, it does not apply to the transportation of flammable, explosive, toxic and precious liquids .
5, Packing seal during use, due to the packing often used in a non-normal state, it exacerbates the damage to the packing and the sleeve wear, making use of packing in a vicious cycle.

The Common Pump failure and Solution

The Common Pump failure and Solution

1. Non-absorbent or not pump water. 

The reasons are the valve blocked or damaged; 
The pump are blocked or the system head over the pump head too much; 
The pumps or the water pipe are leakage;
The rotation stop to run or damaged; 
The impeller turning speed is too low or irregularities; 
The suction tube is leakage or enter gas. 

Solution: The pumps can be taken to repair, removal of debris, fastening, replacement and other methods to solve it.

2. Less than the water pump capacity required or the water vacuum failure. 

The main causes are the pipeline leaks; 
The pump speed slower than required; 
The water level higher than the pump suction joint; 
The filter, impeller, or partially are blocked; 
The impeller damage: 
The department of shaft seal leakage; 
The water pump cover, such as fastening bolts loose. 

Solution: The pumps can be of their inspection, plugging, if it is necessary, they could be replaced or re-installed.

3. Pump vibration or noise. 

The unreasonable installation is the main reason; 
The pump shaft bending; 
The impeller damage or imbalance; 
The bearings are damaged or not lubrication; 
The fixed screws loose; 
The motor drive shaft and pump shaft are not at same level exactly; 
The unbalanced rotor; 
The impeller blocked with rubbing, such as Shell. 

Solution: The pump can be adjusted separately. Alignment, repair, replacement, fastening methods etc. are the rules to solve it.
.
4. Over-temperature of the bearings.

Bearing main causes by serious wear and tear; 
The pump shaft bending; 
Bad lubrication; 
The motor drive shaft and pump shaft are not at same level exactly;
The  bearing improper installation.

Solution: The pump can be replaced, alignment, improve lubrication, adjustment, are the correct way to rule out the installation.

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Or contact roger@angroupcn.com if you are interested!

How is the centrifugal pump flow, head, shaft power, efficiency changing?

Centrifugal pump operating point is determined by the characteristics of the pump curve and the pipe characteristic curve: characteristic pump curve H = Ho - SoQ ^ 2 is a descending curve concave to the characteristics, pipe


curve H = Z2-Z1 + SQ ^ 2 is a concave curve upward increment.


H- pump head, Ho - Pump head when flow is zero, So-- pump friction, Q- pump flow,


Z1- pump sump water level, Z2-- out of the pool water level, S- - pipe friction.


Changes in the degree of opening of the centrifugal pump outlet valve means the pipeline characteristic curve changes.

When the valve opening becomes smaller, the line resistance increases (S increases).

When the pipeline characteristic curve steepens, the intersection of the pump characteristic curves move to flow smaller, bigger lift direction.

When the valve opening becomes large, the opposite. As for shaft power, efficiency is determined by the change in pump and piping characteristic curve characteristic curve. For the pump, the shaft power with the smaller valve opening becomes smaller.

Types of Volutes

Volutes: The word volute actually describes a specific type of pump casing that converts energy created by the impeller into pressure. The impeller pushes water into the volute which converts that energy into pressure and directs the flow toward the discharge point. In the picture on the right notice that the impeller is not located in the center of the volute. This is intentional. The portion of the volute that extends closest to the impeller is called the “cutwater”. It is the point where the flow is forced to exit through the discharge point rather than continuing to swirl around the impeller. The gradually increasing distance between the volute and casing and the direction of rotation of the impeller (noted by the arrow above the volute) combine to force the water around the volute in a counter-clockwise direction in the pump section shown, and once the flow reaches the cutwater it is forced to exit the volute.
Diffusers: There is a second way that is often used in centrifugal pumps to convert energy into pressure. This is through the use of a diffuser. A diffuser functions similarly to a standard volute in that it contains vanes that begin close to the impeller and then gradually extend away from the impeller periphery. However, unlike the volute casing a diffuser casing may contain many vanes. In the case of the assembly drawing shown the diffuser contains 10 vanes as compared the volute casing which only has one.

What are the Main Parts of Every Centrifugal Pump?

Main Parts of Every Centrifugal Pump

From Centrifugal Pump Manufacturer

There are a few components that virtually every centrifugal pump has in common. These components include the impeller, casing, shaft, shaft sleeves, bearings, and seals. These parts can be subdivided into the “wet end” and the“mechanical end”. The wet end of the pump includes those parts that dictate the hydraulic performance of pump. The mechanical end includes those parts that support the impeller within the casing, seal the casing where the shaft passes through it, and enable rotation: the means by which the wet end creates flow and pressure.

Wet End 

We’ve already talked about the two primary parts of a pump: the casing and impeller. So we won’t spend much time on those here. The short explanation is that the impeller rotates at a high speed creating energy. The impeller is positioned within the casing which converts the energy created by the impeller into flow and pressure. For a more detailed look at this process take a look at the article on this topic.

Mechanical End

The impeller is mounted on a shaft. The shaft is usually made of steel or stainless steel and is sized to support the impeller. Impellers have to be sized carefully. An undersized shaft can result in increased pump vibration, shorter bearing life, the potential for shaft breakage, and an overall reduced pump life.Generally speaking the pump shaft is covered with a shaft sleeve. The shaft sleeve is a sleeve of metal, usually bronze or stainless steel, that is designed to either slide or thread onto the shaft. The shaft sleeve is used to position the impeller correctly on the shaft, and it also protects the shaft.

In order for the shaft to hold the impeller within the casing it must pass through the casing. The point where the shaft enters the casing is called the stuffing box and must be sealed. The most typical sealing mechanism is the mechanical seal.

Mechanical seals vary tremendously in design, performance, and cost. The simplest seal consists of just a few primary parts: a stationary face, a rotating face, a gland, and a spring. The rotating face is a ring of smooth hard material that is fastened to shaft sleeve, and the stationary face is a second ring of smooth hard material fastened to the casing. The gland bolts to the outside of the casing and the spring is placed under tension between the gland and the stationary seal face causing it to press against the rotating face. As the pump shaft rotates the rotating face will rotate against the stationary face. A small amount of the pumped liquid will make it’s way between the faces keeping them cool and lubricated. As long as the seal faces stay clean, smooth, and lubricated they will virtually eliminate leakage around the shaft.

The final part of the mechanical end is the bearing arrangement. 

Generally speaking centrifugal pumps are equipped with standard ball-type anti-friction bearings. These are the same bearings used in everything from electric motors, to roller skates, to automobiles, and they are lubricated by grease or oil. The pump shaft is supported and held in place by the bearings which have to be designed to handle all of the loads created by the rotation of the impeller, and sized to provide a reasonable service life. Bearing failures are one of the most common causes of pump downtime so designing Engineers and End-Users will often be particularly interested in the specifics of bearing design, and the pump professional will be well served to spend time learning the ins-and-outs of the bearing systems of the pumps in question.

Summary

Pumps are simple machines. In their simplest form they consist of two hydraulic components and a mechanical support system. Understanding the purpose of these parts is a critical step in the development of every pump professional.