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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

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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

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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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Pump selection: all the parameters

As pump manufacturers, we daily face with a lot of inquiries that are often not complete because of the lack of data that are essential to let us quote the correct pump solution. In order to help our customer to get their way out of the jungle of the parameters, we have defined a table of the main variables that should be considered during the pump selection. This article would like to be a light vademecum to simplify the communication requesting for a quotation.

Variables of the pump selection

The following table includes the indispensable variables that our technicians have to know during the selection. We strongly recommend our customers to communicate the following data so that we can proceed with the selection.

pump selection

Thanks to these references, our technical department will be able to select the best solution for every inquiry.

Moreover, once the selection is done, our technical department will provide the customers with some helpful derived parameters that are necessary for the plants.

Parameters confirmed by the pump technicians

Indeed, after the selection, our technicians, first of all, confirm the actual head and flow that pump can reach and the diameter of the impeller. Then they give the customers the data shown in the table below. This information let our customer be able to technically evaluate our proposal according to the construction features of the plant.

after the pump selection

 

Is it more clear now? Should you need any further information, please contact us at info@gemmecotti.com. We will be glad to dissipate all your doubts.

Don’t forget to save this post in your bookmarks, in order to easily recover it! And to select the right material for the pump, take a look also at our chemical compatibility guide.

References:

https://en.wikipedia.org/wiki/Net_positive_suction_head
https://web.archive.org/web/20170603124924/https://www.ksb.com/blob/333370/f0c49eb441d360b61f48f08ec47d78ab/pdf3-data.pdf

 

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AODD pumps: 4 reasons to choose diaphragm pumps

 

AODD pumpsThe AODD pumps, Air Operated Double Diaphragm pumps, appeared in the pump market for the first time about sixty years ago. Thanks to the constant technological improvement, they have managed to set themselves as the best choice for pumping high-viscosity fluids.

There are four reasons why you should prefer a double diaphragm pump as our HAOD pumps for your plant. Here they are:

  1. VERSATILITY AND VARIETY OF APPLICATION

    The AODD pumps find application in a wide range of installations, thanks to their versatility and to their features. For example: the ability to self-prime, the possibility to run dry, the potential to be submersible, and the possibility to pump high-viscosity fluids. Moreover they are available in different materials in order to overcome any problems of fluid compatibility.

  2. DESIGN AND SIMPLICITY

    The design and the ease of use of the AODD pumps are among the reasons they are so appreciated in the chemical pumps market. Indeed they are often described as “plug-in-and-play” or “set-and-forget” pumps, because once installed and connected to a compressed airline they can work for themselves in full autonomy. They can be provided in a multiplicity of dimensions, easily meeting every customers’ needs.

  3. SAFETY AND ECOLOGY

    Thanks to its closed design, the usage of compressed air as the only power source, and its stall-prevention pneumatic system, AODD pumps are one of the safest pumping system for hazardous liquids, together with the mag-drive pumps. Moreover the ecological design of AODD pumps allows them to realize up to 60% saving in air consumption. Thanks to this saving, their impact on environment decreases significantly. Less air consumption means indeed the possibility to use smaller air compressor, with consequent energy and money saving.

  4. MONEY SAVING

    The money saving, especially in the long-period, is amongst the reasons why you should consider to select a diaphragm pump. The improvements made in diaphragms construction have indeed dramatically increased the life of the diaphragm pumps. They can work properly for years with a very low maintenance, especially thanks to their static seals. These seals maintenance indeed tends to be infrequent and inexpensive.

Have we convinced you? Visit the webpage of our HAOD in order to learn more about air operated pumps. For further information contact us at info@gemmecotti.com. Our technical and sale departments will be glad to lead you to the best choice.

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