The SHD and SHDG series are single-suction, multistage segmental centrifugal pumps. Engineered to perfection, they are adept at transporting water and fluids similar in physical and chemical properties, devoid of solid particles. The SHD model efficiently handles fluids with temperatures below 80 ºC, making it ideal for applications in mines, factories, and urban drainage systems. Meanwhile, the SHDG model is tailored for more intense tasks, managing fluids at temperatures up to 105 ºC, perfectly suited as a boiler feed pump or for the delivery of hot water in demanding environments.
Structural Features
Both SHD and SHDG pump models boast an intricate construction comprising a stator, rotor, bearings, and a sophisticated shaft seal system.
1. Stator Part: This includes inhalation, middle, spit sections, guide vanes, and more. These components are securely clamped together with tension bolts ensuring smooth operation. The SHD model features a horizontal inlet with a vertical outlet, whereas the SHDG model is designed with both vertical inlet and outlet.
2. Rotor Parts: Comprising the shaft, impeller, balance plate, bushings, and other essential components. Here, the shaft transfers power to the impeller, enabling efficient functionality, and axial forces are expertly balanced by the balance plate. Both shaft ends are fortified with replaceable shaft sleeves for enhanced protection.
3. Bearing Part: Available in two types – rolling bearings and sliding bearings.
The Sliding Bearing assembly consists of the bearing body, caps, dust disk, oil level gauge, and rejection mooring rings, lubricated with thick oil for optimal performance. The Rolling Bearing system features a robust body, bearings, and gland, all utilizing grease lubrication for seamless operation.
4. Shaft Seal Parts: With options of mechanical or packing seals, this segment includes water segment, sealed body filler, and tail cover components. The seal chamber liquid performs essential water seal, cooling, and lubrication functions. For SHD pumps, seal water is derived from internal pressure water, whereas, for SHDG pumps, it comes from external cooling or normal temperature water. It is crucial that the seal water pressure exceeds the seal chamber by 0.05-0.1MPa, while cooling water pressure should range between 0.15-0.3MPa.
Furthermore, these pumps operate with precision, being directly driven by a prime motor through a flexible coupling. The pump's rotation is clockwise when observed from the prime motor end.
The versatile SHD and SHDG centrifugal booster pumps can be powered by either an electric motor or a diesel engine, offering flexibility in various operational scenarios.
In the realm of multistage centrifugal pumps, a significant thrust arises due to the alignment of impellers in a single direction. To counteract this, a thrust balance device such as a balance disc or balance drum is employed. This ingenious solution effectively mitigates the thrust, bringing it down to a level that a standard-sized thrust bearing can effortlessly manage.
Our impellers are crafted from premium materials including cast iron, cast steel, stainless steel, and bronze, ensuring superior durability and high performance.
Flexible couplings
Distinct from their rigid counterparts, flexible couplings offer unmatched versatility by accommodating movement such as vibrations and thermal expansion without sustaining damage. They are ideal for scenarios involving unavoidable misalignment between drive and pump shafts, making them invaluable in reducing excessive operating noise. Although they entail a more complex and costly design, their ability to shield shafts and bearings from damage and premature wear translates into significant maintenance savings over time.
In our pumps, we choose to use wear-resisting disc coupling or pin coupling to ensure optimum performance and longevity.
Packing seals have long been the go-to sealing solution, utilizing rope-like materials to wrap around the pump shaft, effectively filling gaps and minimizing fluid leakage. Nevertheless, as time progresses, these seals may wear down, leading to increased fluid loss, impaired lubrication, and potential challenges with replacement.
Mechanical seals have taken precedence over traditional packing seals in applications where leakage must be minimized. These seals offer exceptional durability, designed to withstand significant stresses. By utilizing multiple sealing points, basic mechanical seals significantly reduce leakage, offering a reliable and robust solution.
| Flow rate |
6-1000m3/hr |
| Head rate |
25-650m |
| Speed |
1450-2900rpm |
| Medium temperature |
0-105 ºC |
| Diameter |
40-350mm |
Our versatile Horizontal Centrifugal Boiler Feed Pump with Mechanical Seal Technology is a cornerstone in pressure boosting systems. These systems are perfect for situations requiring a steady, reliable flow and pressure, making them indispensable across diverse projects. Some of the most prevalent applications of our horizontal multistage pump include:
Mine dewatering - efficiently managing water levels in mining operations to ensure smooth and safe production.
High density living - maximizing water supply efficiency in urban environments where demand is high.
Snow making - essential for snow production in resorts, ensuring seamless winter sports activities.
Boiler feed systems - maintaining optimal boiler performance by ensuring a continuous and reliable water supply.
Reverse Osmosis - facilitating high-quality water purification processes for diverse applications.
Industrial applications - serving a wide range of sectors, providing vital support for various industrial processes.
Condensate - effectively managing and recycling condensate for improved efficiency and sustainability.
High pressure cleaning/wash down facilities - delivering the pressure needed for thorough cleaning operations.
Jacking pumps for fire hydrant systems - enhancing the efficacy and reliability of firefighting solutions.
Irrigation and fire hose feed supply - crucial for ensuring water availability for agriculture and emergency services.
Showers - providing consistent water pressure for a comfortable and invigorating shower experience.
Co-generation - supporting combined heat and power systems to maximize energy efficiency.
Spray - enabling precise and controlled spraying operations across various industries.
Pressure Boosting - the ultimate solution for enhancing water distribution efficiency in diverse applications.
A. What are the multi stage pump parts?
The multistage pump parts are very similar to those of the standard Centrifugal pump except for the Multistage Centrifugal pump where the additional parts are diffusers which efficiently channel the fluid into the eye of the impeller or to the following stage. In the side channel pump, there are intermediate plates with the scalloped side channel and liquid parts.
In multistage centrifugal pumps, because of the high thrust that is generated due to the impellers facing in the same direction, there will be a thrust balance device i.e balance disc or balance drum which reduces the thrust to a level which can be managed by a standard sized thrust bearing.
B. How does a multi stage pump work?
A multistage pump operates by one impeller feeding into the next impeller and the number of impellers required depend on the discharge pressure requirement. Liquid enters the pump and then passes through the various number of impellers in a sequence from the left to right.
C. What are the applications and uses for multi stage pumps?
The applications for multi stage pumps are many and varied and can be used for delivering water to high rise buildings, reverse osmosis (RO), boiler feed water, spraying, high pressure cleaning, water works, heating, condensate, fuel delivery, oil and gas production, power generation & mining and other high pressure and temperature applications..
D. What are the different types of multi stage pumps?
Types of multistage pumps include;
Horizontal Multistage Centrifugal pump (above ground)
Vertical Multistage Centrifugal pump (above ground)
Submersible/Sump pump types
Side Channel pump
Combination pumps i.e Centrifugal low NPSH first stage with side channel additional stage.
Horizontal split case pump
Vertical Turbine pump
Sanitary Multistage pump
E. What are the advantages of using a multi stage pump?
If we were to compare the Centrifugal multi stage pump to a high pressure duty pump - the Centrifugal multi stage pump even though it is more complex and costly, it would probably be a better hydraulic fit, have a better efficiency and be more reliable. With its hydraulic modules, the ability to supply additional impellers and its ability to trim those impellers, the duty point can me met exactly without compromise. The selection is more likely to be close to 'BEP' and will run efficiently and reliably.
Multi stage pumps can be configured to have an interstage bleed off if there are multiple duty points required. It may be possible to run a multistage pump at a lower speed than a single stage centrifugal pump which may offer an efficiency advantage but it will certainly run much quieter which is an important consideration in today's world. A 3 dBA increase represents a doubling of sound as the sound scale is logarithmic.
F. What is difference between a single stage and a multi stage pump?
A single stage pump uses one impeller whereas a multi stage pump uses 2 or more impellers (some manufacturers use 80 or more impellers).
There are additional components in a multi stage pump which are required for channelling the fluid from the first stage to the following stage i.e diffusers.
Multi stage pumps have a thrust balance device and there may also be intermediate bearings (lubricated by the pumpage) to steady the shaft plus other minor differences.
G. How do you read a multistage pump curve?
You read a multi stage pump curve in exactly the same way as you read any other pump type curve however some manufacturers will publish single stage curves which means that this has to be multiplied out to establish the number of stages required, however be aware that the side channel pumps have their maximum power at zero flow and the power decreases with increasing flow which is the reverse of a centrifugal pump.
H. What is the difference between a vertical multistage pump and a horizontal multistage pump?
The main differences between a vertical multi stage pump and a horizontal multi stage pump are;
1.The orientation of the pump
2.The vertical multi stage pump is above ground and may be used where there are space limitations however the motor needs to be removed before maintenance can be performed.
3.Vertical multi stage pumps are used in some applications where the motor needs to be lifted from the sump so that the unit can be maintained. It is common in vertical pumps for the thrust load to be taken by the motor e.g. VTP turbine pumps which have electric motors specifically designed for this type of pump to eliminate the need for a thrust bearing in the pump resulting in less complexity and costs. VTP pumps can be produced with column lengths of more than 100 metres.
4.Horizontal multi stage pumps are mounted using feet which for high temperature applications are a special design to allow for thermal growth and thus avoid operating issues due to expansion and contraction. They would need to be aligned with the electric motor. On vertical pumps, the mounting is perhaps simpler i.e for sump pumps, a support plate would be fixed with standard bolting and generally no alignment is required as the motor is flanged and it is self aligning with the corresponding register.
I. Which type of multistage pump is more commonly used in industry?
The most common type of multi stage pump used in Industry is the horizontal multi stage pump and vertical multi stage pump (above ground) mounted centrifugal pumps. However, multi stage side channel pumps would also be relatively common along with the vertical turbine pumps.
SEMHAI can offer a full range of Flowserve's Multi stage pumps.We provide localised technical support & on-site service engineering to support your operational needs.
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