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centrifugal pumps

Centrifugal pumps: characteristics and functioning

Centrifugal pumps are used in a very wide range of industries, from chemical-petrochemical to textile to water treatment, electronic, etc.
If you are looking for accurate and specific information regarding centrifugal pumps, you are in the right place! In the following paragraphs, in fact, we are going to explain their characteristics and how they work.

Centrifugal pumps: classification

Based on the position of the drive shaft that moves the impeller, there are two types of centrifugal pumps: 

  • horizontal pumps 
  • vertical pumps: suitable for applications where installation of the pump semi-submersed in the liquid is required (tanks, reservoirs, sumps etc.)

Horizontal centrifugal pumps can be installed: 

  • above the fluid level: in this case, the pump has to be self-priming
  • below the fluid level: the pump is installed below the liquid level so it is flooded

Centrifugal pumps are composed of an impeller, assembled on the motor shaft, which rotates inside the pump head. The liquid enters in the axial direction but different types of pumps have different outflow directions:

  • Radial flow pumps (most common)
  • Axial flow pumps
  • Mixed flow pumps

Centrifugal pumps: components

The main components are:

  • the pump head (or pump casing)
  • the impeller, which is connected to the motor shaft. You can choose between different types of impellers for centrifugal pumps: open, which is used with liquids with a higher concentration of impurities; closed, when there is a smaller percentage of suspended solids; semi-open etc. 
  • the shaft
  • the motor
  • Sealing system to prevent liquid leakage between the pump head and the shaft

There are different types of sealing systems, such as: 

  • mechanical seal pumps, in which the pump shaft, connected to the impeller, exits to the outside to be connected to the motor, and a mechanical seal is installed to ensure sealing
  • mag drive centrifugal pumps in which the external magnet is assembled directly on the motor shaft and it transmits motion to the impeller by means of an internal magnet through magnetic force. In this case, the shaft does not pass to the outside of the pump. 

The external magnet placed on the drive shaft transmits the motion to the internal magnet connected to the impeller which rotates and moves the fluid through the pump. So the containment rear casing contains the internal magnet mentioned above and it ensures a hermetic seal on the hydraulic part of the pump, keeping it separated from the motor.

The figure below shows the main components of these pumps:

Centrifugal pumps: functioning

How does a centrifugal pump work? Operating curves and graphs can be used to describe their performance and area of work.
For a centrifugal pump, the performance curves can be seen in graph 4.1 while graph 4.2 shows the case of a positive displacement pump:

graph 4.1pumps curves positive displacement pump curves graph 4.2

The top graph in both figures describes the head variation given by the pumps as the flow rate changes. The best performance is recorded by working centrally, both on the x-axis and y-axis. So between 2 and 2.5 m3/h and between a head of 4 and 5 m. 

For the proper functioning of a centrifugal pump plant, it is necessary to verify that the NPSH available in the plant is higher than the NPSH required by the pump.

We will not expand on the explanation of NPSH here but you can refer to the following link: https://www.gemmecotti.com/npsh-a-brief-explanation/

GemmeCotti centrifugal pumps

GemmeCotti can supply four different models of mag drive pumps and one model of mechanical seal pumps: 

HTM PP/PVDF and HCM PP/PVDF – MAG DRIVE CENTRIFUGAL PUMPS

  • thermoplastic pumps made in PP or PVDF
  • capacity up to 130 m3/h
  • head up to 48 mlc
  • HTM : injection molded parts – HCM: casing machined from a block

HTM mag drive centrifugal pump           HCM mag drive centrifugal pump

HTM SP – SELF-PRIMING MAG DRIVE CENTRIFUGAL PUMPS

  • thermoplastic pumps made in PP or PVDF
  • capacity up to  25 m3/h
  • head up to 22 mlc
  • injection molded parts
  • self-priming up to 6 m

HTM-SP self-priming mag drive pumps

HTM SS 316 – AISI 316 MAG DRIVE CENTRIFUGAL PUMPS

  • thermoplastic pumps made in AISI 316
  • capacity up to 32 m3/h
  • head up to 24 mlc

HTM SS316 mag drive centrifugal pump

HCO – MECHANICAL SEAL CENTRIFUGAL PUMPS

  • thermoplastic pumps made in PP or PVDF
  • Flow up to 130 m3/h
  • Head up to 48 mlc

HCO mechanical seal pump

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plastic pumps

Plastic pumps: characteristics and advantages

GemmeCotti plastic pumps for acids and dangerous liquids

GemmeCotti has been producing pumps for acids and dangerous liquids for over 30 years in special materials: plastic pumps are mainly made of PP (polypropylene) or PVDF and stainless steel pumps are mainly made of AISI 316. The use of these materials ensures compatibility with a wide range of liquids such as acids, bases, oils, alkalis, refrigerants and fuels. 

In this article, we will focus on the plastic materials used for the complete range of our chemical pumps. We will analyze their main features and discover why plastic pumps are especially suitable for pumping corrosive and dangerous liquids such as sulfuric acid, sodium hydroxide, hydrochloric acid, acetone, cleaners, petrol, diesel, phosphoric acid and seawater.

Most of the PP and PVDF injected plastic parts used in GemmeCotti pumps are manufactured by Gemme Plast, a part of the GemmeCotti group, which specializes in the injection molding of plastic materials. 

Features of the plastic materials 

Our pumps are often used with fluids that can be corrosive and very aggressive, so it’s very important to use highly resistant and compatible plastic pumps. The pumps made of plastic materials are: 

Polypropylene [PP] pumps

PP (Polypropylene) is the main plastic material we use for our pumps. It is one of the most common polymers and, historically, one of the first to be used in industry.
Polypropylene was discovered in 1954 by Italian chemical engineer Giulio Natta, following the work of Karl Ziegler in Germany. Their innovative studies on stereospecific polymerization, which led to the discovery of crystalline polypropylene, earned them the Nobel Prize in Chemistry in 1963.
PP is highly resistant and therefore can be used with many fluids like caustic soda (or sodium hydroxide) and acid liquids. Polypropylene is reinforced with other materials like glass fiber and talc to make it more mechanically resistant and to ensure a higher resistance to pressure.
Polypropylene is perfect for obtaining injection molded parts, and the pumps made of this material can safely withstand fluid temperatures of about 60-70°C.

Plastic pumps in PVDF 

The second most important material we use for GemmeCotti plastic pumps is PVDF, which is a fluoropolymer, i.e., a technopolymer with advanced properties. Its composition makes it chemically inert to most chemicals. Since this kind of plastic is difficult to synthesize and is used in more limited and specialized sectors, it costs more than PP. However, It is significantly more resistant to high temperatures compared to polypropylene and it can be used at higher temperatures, up to 90°C.
This material too is reinforced to increase its mechanical resistance. 

How to choose the most suitable pump material

In order to decide whether PP, PVDF or stainless steel AISI 316 is the most suitable material you must:

  • first, know the liquid that has to be pumped, which is in contact with the pump and verify its compatibility. You can use the GemmeCotti chemical compatibility chart available at this link;
  • and then know the temperatures of the liquids to be pumped. Polypropylene is the most suitable plastic material for liquids with maximum temperatures of 60-70°C, while PVDF is preferred for temperatures up to 90 ºC.  When the temperature of the liquid exceeds 90 ºC, you can check its compatibility with stainless steel AISI 316, a material that can work with even higher temperatures.

Plastic injection molding

The GemmeCotti group includes the sister company Gemme Plast, which makes injection molded parts. Plastic parts are injection molded, a production technique widely used for the processing of most thermoplastic polymers. We produce plastic parts that are used for the production of GemmeCotti pumps and that is why we are able to control the quality of our production and guarantee our customers fast delivery with significant savings.
Gemme Plast has a range of different tonnage presses, which make it possible to inject plastic parts of various sizes according to need. So we can offer pumps with a very wide range of performance, varying from 0.5m3/h to 150m3/h.

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INDUSTRIAL PUMPS FOR SCRUBBERS

APPLICATION: INSTALLATION OF CHEMICAL PUMPS IN SCRUBBER PLANTS

The emission of gasses in the atmosphere is regulated by specific national and international laws that must be respected by all industries. The term “air treatment” refers to systems and techniques used by the industries to keep the air quality and the level of pollution under control.

Scrubbers are the easiest and most efficient systems for purifying the air by removing particulates and/or gasses.

There are several types of scrubbers which are used in different industrial sectors.

Plants

FLUIDS GENERALLY INVOLVED IN THIS APPLICATION:

Scrubbers are generally used to:

  • wash fumes (e.g. emitted by boilers or furnaces) with soda or other liquids, in order to remove hydrogen sulfide, hydrochloric acid, hydrocarbons and sulfur dioxide.
  • depurate gasses (e.g. washing synthetic gasses with monoethanolamine in order to remove CO2).

Scrubbers are generally used by:

  • petrochemical industries
  • chemical and pharmaceutical industries
  • galvanic industries
  • packaging industries
  • food industries
  • cellulose industries

INDUSTRIAL PUMPS INSTALLED IN AIR TREATMENT AND FUME DEPURATION SYSTEMS

scrubber

The polluted air is directed inside a chamber where it comes into contact with the washing liquid which transfers the pollutants from the air to the water. The purified air is released into the atmosphere while the polluting particles become an integral part of the washing liquid, which is then collected in a tank.

During this process, the polluted air goes from the bottom to the top while the washing liquid is pushed up by the use of centrifugal pumps and then it goes from the top to the bottom through the scrubber. The washing liquid collected in the tank is then recirculated by means of horizontal centrifugal pumps installed on the ground or through vertical pumps installed directly inside the tank. The pump continues to recirculate the same liquid which, after the transfer through the scrubber, returns to the tank.

SPECIFIC REQUIREMENTS FOR THIS APPLICATION: WHICH ARE THE BEST PUMPS FOR AIR TREATMENT AND FUMES DEPURATION SYSTEMS?

Additives inside the washing liquid are often hazardous chemical agents. For this reason it is necessary to use anti-corrosion pumps.

The pump used in this process can be installed next to the tank or vertically immersed in it.

In both cases, GemmeCotti offers suitable solutions:

Horizontal centrifugal pumps:
– series HTM PP/PVDF (magnetic driven)
– series HCO (mechanical sealed)
are the best solution for the installation next to the tank.

Vertical centrifugal pumps:
– series HV (monoblock)
– series HVL (with bracket)
are the ideal solution for installation with the pump immersed in the tank.

All these centrifugal pumps are made of thermoplastic materials PP or PVDF, which ensure a great chemical resistance to the chemical agents used in this application.

GEMMECOTTI CENTRIFUGAL PUMPS FOR THE AIR TREATMENT

MAGNETIC HORIZONTAL CENTRIFUGAL PUMPS SERIES HTM PP/PVDF

Mag drive pumps HTM PP/PVDF have a sealless design that is particularly suitable to pump corrosive and dangerous liquids; the magnetic design together with the usage of anticorrosive thermoplastic materials, ensures the high chemical resistance and the absence of leakage and emissions.

GemmeCotti HTM scrubbers

Technical data:

– Capacity up to 130 m3/h

– Head up to 48 mlc

Discover more

HORIZONTAL CENTRIFUGAL MECHANICAL SEAL PUMPS SERIES HCO

Mechanical seal centrifugal pumps HCO are the best solution when the liquid has solids in suspension: their design with open impeller permits to transfer dirty liquids (non-abrasive solids – max. 5% – dimension max. 3 mm).

Technical data:GemmeCotti HCO scrubbers

– Capacity up to 60 m3/h
– Head up to 38 mlc

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VERTICAL CENTRIFUGAL PUMPS

Vertical centrifugal pumps are suitable for installations with the pump immersed directly in the tank.

VERTICAL CENTRIFUGAL MONOBLOCK PUMPS SERIES HVGemmeCotti HV scrubbers

Pumps series HV are available with different column lengths from 500 mm to 1000 mm.

Technical data:

– Capacity up to 40m3/h
– Head up to 22 mlc

Discover more

VERTICAL CENTRIFUGAL PUMPS WITH BRACKET SERIES HVL

Pump series HVL are available with different column lengths from 500 mm to 2000mm.

Technical data:                                                                    GemmeC

– Capacity up to 57m3/h
– Head up to 39 mlc

Discover more

 

 

 

Contact our commercial department, we will find together an interesting solution for your application: info@gemmecotti.com

 

 

 

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HTM SP: OUR NEW MAG DRIVE CENTRIFUGAL PUMP SELF-PRIMING

HTM SP mag drive centrifugal pump self-priming

We are extending our product line: our new pump is ready!

We are happy to announce our new mag drive centrifugal pump self-priming HTM SP!

GemmeCotti HTM SP pumps combine the typical features of our mag drive centrifugal pumps with the self-priming capability. These pumps can prime up to 6 meters at sea level.

MAIN FEATURES

MATERIALS

HTM SP pumps are made of Polypropylene (PP), a thermoplastic material that ensures the best resistance to most chemicals.

All the internal plastic parts are obtained through the injection moulding process that we directly manage in our sister company Gemme Plast.

PERFORMANCE CAPABILITY

The new magnetic centrifugal pump self-priming HTM SP can reach a capacity of 25 m3/h and a head of 22 m.

The suction connection of this pump can be customized in 3 welded configurations according to your needs (frontal, on the right and on the left).

HTM SP curves

MAGNETIC DRIVE PUMP SYSTEM

Mag drive pumps have a special sealless design that is suitable for pumping corrosive and dangerous liquids thanks to the high chemical resistance and to the absence of leakage and emissions. The structure is really simple and it requires very little maintenance with consequent savings in terms of repairing, spare parts and machine downtime costs during the pump life.

In magnetic pumps, there is an external magnet which is connected to the shaft of the electric motor.
The synchronous motion is transmitted from the motor to the rotor (consisting of the internal magnet and the impeller) through the external magnet. The two magnets never come into contact, they are moved by the magnetic field only. The impeller connected to the internal magnet spins around a static shaft and the liquid moves through the pump. The whole hydraulic part is hermetically sealed: in the space between the magnets there is a rear casing which closes on the pump head and prevents the pumped liquid from coming out of the pump.

The pumped liquid must be clean, without solids in suspension (max. quantity of solids: max 2% – max 1mm).

Read more about the magnetic system

TECHNICAL DATA

• Materials available: PP or PVDF*;
• Materials in contact with the liquid: Pump housing: PP; Impeller: PP or PVDF;
O-ring: EPDM (standard for PP pumps) / VITON
(standard for PVDF pumps); Static shaft: Al2O3 99.7%; Bearing: PTFEC.
• Capacity up to 25 m3/h.
• Head up to 22 m.
• Max temperature: PP: 70° C – PVDF: 90° C.
• Max viscosity: 200 cSt.HTM SP connections
• Pressure rating: PN6 at 20° C.
• Self-priming up to 6m at sea level.
• Suction connection available in 3 welded configurations
(frontal, on the right and on the left).
*Pump housing only available in PP.

STANDARD:
• Gas threaded In and Out connections.
• Direct starting motor.

OPTIONAL:
• Baseplate.

   

   HTM SP is now available!

                       Contact our office at info@gemmecotti.com for any further information.        

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HTM PP PVDF NOW AS THEN: THE 7 STRONG POINTS OF OUR BEST-SELLER SERIES

Since 1992 GemmeCotti has been manufacturing several types of high quality chemical pumps suitable for most industrial applications.

Everyday we employ all our experience to improve the existing products and to design new projects in order to satisfy our customers’ needs. We live in the present and we design the pumps of the future without forgetting where we started.

The magnetic drive centrifugal pump HTM PP/PVDF was our first product, the one which made us experts in the field of the pumping solutions.

HTM 10 mag drive centrifugal pump

Over the years we developed the series that now includes 9 sizes: HTM 4, HTM 6, HTM 10, HTM 15, HTM 31, HTM 40, HTM 50, HTM 80, HTM 100. Each size is available in two thermoplastic materials: PP (polypropylene) and PVDF.

The HTM are high-quality pumps, extremely reliable and versatile, and they are still our bestsellers.

Which are the 7 strong points of these mag drive centrifugal pumps?

1. MATERIALS OF CONSTRUCTION

The HTM pumps are manufactured in thermoplastic materials, PP or PVDF. These anti-corrosion materials are compatible with the great majority of the acids, chemicals and dangerous liquids.

Check the chemical compatibility chart

2.INJECTION MOULDING

The plastic parts of our HTM are manufactured by Gemme Plast, another company in the GemmeCotti group, which is specialized in the injection moulding of plastic. Thanks to this cooperation, we can check all the raw materials used and we have total control over the moulding process.

3.LEAKLESS MAGNETIC DESIGN

Advantages of the magnetic drive system:

  • no mechanical seal
  • no leakage or emissions
  • no waste of liquidsHTM magnetic drive system
  • environmental sustainability
  • reliability and safety
  • low maintenance and consequent long term savings
  • no need for a pump-motor alignment

Please note that the liquid must be clean and without solids in suspension (acceptable quantity and dimensions of the solids: max 2% – max 1mm).

Discover more about the mag drive advantages

4.RELIABILITY

Unlike most centrifugal pumps on the market, the pump head of the HTM is secured to the bracket with 8 bolts. This feature allows the safe fastening of the pump head, ensuring the static seal and avoiding the deformation of the pump head due to the pressure.

5.BEARINGS

The wide dimensions of the frontal bearings ensure the high resistance to the axial thrusts.

6.STATIC SHAFTHTM magnet and shaft

The static shaft of the mag drive centrifugal pumps HTM is made of alumina (Al2O3), an extremely robust ceramic material that ensures great stability and resistance to most hazardous liquids.

7.MAGNETS

The HTM pumps series are equipped with a high magnetic coupling created with magnets made of NdFeB. Thanks to this particular feature, the internal and external magnets won’t detach from each other while the pump is operating.

 

 

    Check the technical data of our HTM

 

 CONTACT US: INFO@GEMMECOTTI.COM

OUR COMMERCIAL DEPARTMENT IS AVAILABLE FROM MONDAY TO FRIDAY, FROM 8.30 TO 12.30 AND FROM 14.00 TO 18.00 TO HELP YOU SELECT THE BEST CHEMICAL PUMP FOR YOUR APPLICATIONS.

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INDUSTRIAL PUMPS FOR UNLOADING TRUCKS

APPLICATION: CHEMICAL PUMPS TO UNLOAD TANKER TRUCKS AND RAILROAD TANK CARS

GemmeCotti supplies industrial pumps suitable to unload railroad tank cars and tanker trucks containing acids and toxic chemicals.

truck-unloading-h-ibc

We offer three possible solutions for this application:

  • installation of one pump for each single tank
  • installation of the pump directly aboard the vehicle (GemmeCotti series HTM or series HCO)
  • use of the portable pump H-IBC (GemmeCotti series HTM 10)

SPECIFIC REQUIREMENTS FOR THIS APPLICATION: WHICH ARE THE BEST PUMPS FOR TANKERS OFFLOADING?

The right pumping solution for unloading and transferring dangerous liquids from vehicles (trucks or railroad tank cars) is selected according to the chemical compatibility and the requested performances.

GemmeCotti pumps are the best choice to transfer dangerous or hazardous goods, i.e. all the substances which, due to their peculiar properties, could be harmful for the environment or the people involved.

These liquids are classified according to their characteristics and degree of danger. In Europe, the transportation of toxic chemicals is regulated by specific laws:

  • ADR: agreement concerning the international transport of dangerous goods by road
  • RID: international carriage of dangerous goods by railrailroad-tank-cars
  • ADN: carriage of dangerous goods by inland waterways

GemmeCotti is proud to offer pumping solutions for the safe handling of chemicals: we supply chemical pumps suitable for the safe offloading of the great majority of dangerous or hazardous goods.

Fluids generally involved in this application:

  • ammonia
  • sulphuric acid
  • nitric acid
  • hydrochloric acid
  • sodium hydroxide (caustic soda)
  • hydrogen peroxide

…and many more!

Check the chemical compatibility guide

WHICH IS THE BEST TYPE OF PUMP TO CHOOSE?

The GemmeCotti pumps installed on means of transport and involved in the unloading process, permit to direct and move the fluids in total safety, ensuring quick execution.

For this application, GemmeCotti recommends:

  • magnetic drive centrifugal pumps series HTM PP/PVDF
  • mechanical seal centrifugal pumps series HCO

The design of these two types of centrifugal pumps, permits the safe installation both on land and aboard the vehicle, ensuring a constant flow without the risk of leakage or emissions.

Magnetic pumps series HTM PP/PVDF

Mechanical seal pumps series HCO

Another practical and effective solution is the use of the GemmeCotti portable pump series H-IBC.

gemmecotti-h-ibc-pumps-

GemmeCotti H-IBC has been designed as a safe and reliable mobile pump specifically for the safe unloading of IBC containers. The unit consists of a magnetic centrifugal pump HTM 10 mounted in a robust carry case, conceived to be easy to move. Thanks to its fast connections, H-IBC is a really flexible solution: the pump could be easily removed from the IBC container and placed in another one according to the requirements. This quick and efficient unit is suitable for several applications. Moreover, the pump is equipped with an electric panel and a start and stop switch for easy, quick and safe use.

Upon request, H-IBC pumps can be supplied in a premium version with wheels, for easier movement and transportation.view-h-ibc

Learn more about our portable pumps H-IBC series

HOW TO AVOID THE RISK OF DRY RUNNING DURING THE PROCESS OF TANKERS UNLOADING?

To prevent damages to the pumps due to the lack of liquid, GemmeCotti supplies the dry running protection device. This device is particularly recommended during the operations of tanker unloading and for all the applications in which there is the risk of liquid shortage.

Thanks to the adjustable threshold and timer, it is possible to set up the minimum power and operation time of the device. If the power is lower than the set value, the pump will automatically stop.

Main features of the dry running protection device:

Dispositivo contro la marcia a secco - dry running protection device

Single Phase CURRENT RELAY

Multirange 15-35A

2 set points MAX / min

Also for motors with INVERTER

 

More information about the device 

MAGNETIC DRIVE CENTRIFUGAL PUMPS AND MECHANICAL SEAL PUMPS

It is fundamental to choose the right pump model when dealing with acids or corrosive liquids. For theGemmeCotti HTM e HCO chemical pumps operations of tanker unloading, GemmeCotti suggests the use of mechanical seal centrifugal pumps or magnetic centrifugal pumps. The type of pump is selected according to the liquid to be pumped and to the requested working point.

MAGNETIC DRIVE CENTRIFUGAL PUMPS

Mag drive pumps have a sealless design that is particularly suitable to pump corrosive and dangerous liquids; the magnetic design together with the usage of anticorrosive materials, guarantees the high chemical resistance and the absence of leakage and emissions.

Moreover, the structure of magnetic drive pumps is really simple and requires very little maintenance with a consequent saving in terms of repairs and spare parts expenses during the pump life. The external magnet placed on the drive shaft transmits the motion to the internal magnet connected to the impeller, which rotates and moves the fluids through the pump.

MECHANICAL SEAL PUMPS

Mechanical seal centrifugal pumps are the best solution when the liquid has solids in suspension: their design with open impeller permits to transfer dirty liquids and fluids with high viscosity.

The seal of these pumps is composed of a static ring and a rotating ring placed on the pump shaft, which is directly coupled to the motor shaft. When the pump is working, the two rings’ surfaces slide together and the lubrication of the parts is granted by the pumped liquid.

 

GemmeCotti supplies pumps for chemicals suitable for the offloading process of tanker trucks, petrol tankers and railroad tank cars. Our industrial pumps allow you to unload the fluids with the maximum efficiency, ensuring safety, reliability and saving in terms of repairs and spare parts expenses.

Upon request, GemmeCotti pumps can be supplied with single phase motors and in ATEX version for potentially explosive areas.

 

Contact us: info@gemmecotti.com

 

Our sales department is available from Monday to Friday, from 8.30 to 12.30 and from 12.30 to 14.00, to select the best chemical pump for your needs.

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INDUSTRIAL PUMPS FOR BIG AQUARIUMS: APPLICATIONS WITH FRESHWATER AND SEAWATER

APPLICATION: THE PUMPING SYSTEM OF BIG AQUARIUMS

The fish tanks of big aquariums allow the public to admire many fascinating underwater creatures. Through hundreds of windows the enchanted visitors look at the wide variety of plant and animal species which populate lakes, rivers and oceans of the planet.

Aquarium pumps

The invisible and complex pumping system of big aquariums permits the survival of aquatic species in freshwater and seawater inside the exhibition tanks. The circulation and filtration of the water is possible thanks to the pumps which direct the liquid through the filter before returning it to the tanks.

The pumping system must guarantee the quality of the water by maintaining its main chemical and physical properties in order to recreate the natural habitat of the aquatic flora and fauna.

The pumps used in these giant freshwater and saltwater aquariums must be corrosion resistant and able to pump large amounts of liquid. Moreover the pumps must be silent to avoid the risk of creating a stressful situation that could alter the normal fish behaviour.

 

SPECIFIC REQUIREMENTS FOR THIS APPLICATION: WHICH ARE THE BEST PUMPS FOR APPLICATIONS IN BIG AQUARIUMS PUMPING SYSTEMS?

Pumps made of thermoplastic materials are recommended for large systems pumping saltwater or freshwater.

The thermoplastic materials used in the manufacture of GemmeCotti pumps are solid and lightweight and they don’t absorb water. Certainly, the best material for the construction of saltwater pumps is polypropylene (PP), a thermoplastic polymer with a good thermal, mechanical and abrasive resistance.

The use of this anti corrosion material, instead of the installation of pumps in metallic materials, avoids the risk of dispersion of metallic particles, which could harm the health of the sea fauna.

WHICH IS THE BEST TYPE OF PUMP TO CHOOSE?

Centrifugal pumps are the best choice for freshwater and seawater aquariums.

A centrifugal pump is made of a movable part called the impeller that forces the liquid under pressure in a desired direction.

GemmeCotti HTM 10 PP centrifugal pump

MAGNETIC DRIVE CENTRIFUGAL PUMPS

Centrifugal pumps can be designed with a particular system called magnetic drive.

Mag drive pumps have a sealless design that is particularly suitable to pump corrosive and dangerous liquids; the magnetic design together with the usage of anticorrosive thermoplastic materials, guarantees the high chemical resistance and the absence of leakage and emissions. Thanks to the total absence of emissions and leakage, the plant will always be clean; this feature coupled with the reduced maintenance required by GemmeCotti pumps, helps in keeping the plant efficient, secure and reliable.

The structure of magnetic drive pumps is really simple and requires very little maintenance with a consequent saving in terms of repairs and spare parts expenses during the pump life.

The use of mag drive centrifugal pumps in thermoplastic materials, such as GemmeCotti pumps series HTM PP/PVDF, is the best solution for working with fresh water and sea water. In particular, the smallest models of this series (HTM 4, HTM 6, HTM 10) are particularly recommended for the pumping system of big aquariums.

 

Check the technical data and download the complete catalogue!

 

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HAOD PNEUMATIC PUMPS: RELIABILITY AND VERSATILITY

GemmeCotti supplies air-operated double diaphragm pumps suitable to transfer aggressive liquids with high viscosity and solids in suspension.

HAOD air-operated double diaphragm pumps

The main feature of HAOD pumps is their versatility: these volumetric self-priming pumps are suitable for applications in chemical and pharmaceutical industries and in water treatment plants. Moreover HAOD pumps are commonly used in dosing systems and they are usable for trucks or barrels.

 

HAOD pneumatic pumps installation

 

HAOD assure high pressures and high heads in addition to the compatibility with a wide selection of liquids. HAOD pumps are built with an anti-stalling pneumatic circuit which ensures the highest possible level of security and efficiency and doesn’t require lubricated air: the ecological design guarantees a reduction in the air consumption.
Moreover, HAOD are fast and easy to assemble without the use of special tools.

HAOD pneumatic pumps are available in several materials and dimensions: diaphragms are made of PTFE while the pump body can be manufactured in thermoplastic materials (PP or PVDF) or metallic materials (stainless steel AISI 316).

Air-operated double diaphragm pumps are available in ATEX version for potentially explosive atmosphere classified zone 2 II3G.

 

MAIN FEATURES:

• Available in PP, PVDF and AISI316;
• Max. Temperature:
PP: 60° C – PVDF: 95° C – AISI 316: 95°;
• Adjustable capacity and head;
• Adjustable speed without pressure loss.

OPTIONAL:
• Pulsation damper.

 

CHECK THE TECHNICAL DATA AND DOWNLOAD THE COMPLETE CATALOGUE!

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GEMMECOTTI ATEX PUMPS: THE EM SERIES

GemmeCotti supplies ATEX pumps for potentially explosive atmospheres. Our EM pumps are suitable to be used in ZONE 1 II2G and ZONE 2 II3G classified areas. All our pumps comply with the technical and safety requirements of ATEX Directive 2014/34/EU

The Directive states that the manufacturers of equipment intended for use in potentially explosive atmospheres shall draw up a written declaration of conformity of these products.

HOW ARE THE ATEX ZONES CLASSIFIED?

The term “ZONE 1” indicates an area where an explosive atmosphere consisting of a mixture of air or flammable substances (gas, vapour or mist) is likely to occur in normal operation occasionally.

The term “ZONE 2” indicates an area where an explosive atmosphere consisting of a mixture of air and flammable substances (gas, vapour or mist) is not likely to occur in normal operation. If it does occur, it will persist for a short period only.

WHAT DOES GEMMECOTTI OFFER FOR POTENTIALLY EXPLOSIVE ATMOSPHERES?

GemmeCotti ATEX pumps for potentially explosive atmospheres EM series includes 3 metallic pumps (AISI 316) and 5 plastic pumps (PP/PVDF).

ATEX PUMPS made of stainless steel AISI 316 suitable for ATEX ZONE 1 II2G and ZONE 2 II3G:

– EM-C Atex centrifugal mag drive pumps:
Max flow 32 m3/h, max head 24 mlc
– EM-P Atex rotary vane mag drive pumps:
Max Flow 2100 l/h, max head 13 bar
– EM-T Atex turbine mag drive pumps:
Max Flow 7 m3/h, max head 78 mlc

GemmeCotti ATEX pumps in AISI 316

ATEX PUMPS made of plastic materials PP/PVDF suitable for ATEX ZONE 2 II3G:

– EM-C PP-PVDF Atex centrifugal mag drive pumps:
Flow up to 130 m3/h, head up to 48 mlc
– EM-T PP-PVDF Atex turbine mag drive pumps:
Max capacity: 9 m3/h, max head: 50 mlc
– EM-P PP-PVDF Atex vane mag drive pumps:
Max flow: 1000 l/h, max pressure 5 bar
– EM-T SP Atex turbine self-priming pumps:
Max flow: 6 m3/h, max head 24 mlc
– EM-CO Atex mechanical seal pump:
Flow up to 58 m3/h, head up to 38 mlc

GemmeCotti ATEX pumps in PP PVDF

ALL THESE PUMPS ARE SUITABLE TO TRANSFER:

  • Acids and bases
  • Corrosive, toxic and dangerous liquids
  • Hydrocarbons, pyrophorics and other flammables
  • Heat transfer oils
  • Refrigerants and cryogenics
  • Radioactive liquids

Our ATEX pumps are suitable for various applications and they are supplied with the ATEX certificate for ATEX ZONE 1 and 2.

You should specify the ATEX zone in your enquiry, our sales office will select the right pump according to your requirements.

All the pumps include the required protective systems.

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NPSH: a very brief explanation

NPSH (net positive suction head) is one of the main parameters to be considered when selecting a pump. But what are we referring to when we talk about NPSH? And why is it so important?
First of all, we have to distinguish two different values of NPSH: the NPSH available and the NPSH required.

NPSH AVAILABLE

The NPSH available, normally shortened as NPSHa, is a value calculated by the plant engineer. It could be roughly defined as the result of the absolute pressure of a fluid at the inlet of a pump minus the vapour pressure of the liquid. It is usually expressed in meters.

NPSH REQUIRED

The NPSH required (NPSHr) is a value that is given by the pump supplier and describes the energy losses that often occur inside the pumps when the liquid enters through the impeller eye of the pump. The value is expressed as a head of fluid (usually in meters). This is a requirement of the pump and it depends on different factors: the design and dimensions of the impeller, the speed of the pump,
the speed of the flow rate, and so on.

NPSH: WHY IS IT SO IMPORTANT?

As we said, NPSH is fundamental in selecting and sizing a pump. Indeed, NPSHa has to be higher than NPSHr for the pump to work properly. If not, cavitation could occur, reducing the performance of the pump and, in many cases, seriously damaging it.NPSH scheme

Cavitation is a physical phenomenon that can happen in a pump. It causes the formation of little gas bubbles inside the liquid when the system pressure goes below the vapour pressure of the fluid. These bubbles instantly collapse when the fluid is inside the impeller, beyond the impeller inlet, due to the increasing of the pressure. The collapse produces microjets with a very high impact on the impeller, which gets significantly damaged. Because the impeller is unbalanced, vibrations and all the related issues can arise: seal failure and bearings serious damaging.

NPSHa > NPSHr

For this reason, the plant engineer has to keep NPSH values in mind at all times. The pump performance curve usually includes a NPSHr graph so that the engineer can check the operating conditions. As a matter of fact, it’s necessary for the NPSHr of the pump to be lower than NPSHa in the plant. The safety margin between NPSHr and NPSHa has to be minimum of 0.5 meters.
Only if this ratio is respected the pump will work properly and cavitation will be avoided.

npsh curve 1

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