Plastic double diaphragm pumps

PP double diaphragm pump

  • Plastic materials: PP, PVDF, ECTFE.
  • Pumps with a non-lubricated air operating system.
  • Stall-free pneumatic motor/exchanger.
  • Self-priming from a dry start.
  • Max air supply pressure: 7 bar.
  • Fine tuning of motor speed at constant pressure.

Plastic double diaphragm pumps

Q max H max Connections Atex Material
Liquid Air
sm_bx5 BX5 5 l/min 70 m w.c. G ¼” G 1/8″ Zone 1 and 2 PP – PP/CF
bx15  BX15 17 l/min 70 m w.c. G 3/8″ G 3/8″ Zone 1 and 2 PP – PP/CF – ECTFE
bx30BX30 30 l/min 70 m w.c. G ½” G ¼” Zone 1 and 2 PP – PVDF
bx50BX50 50 l/min 70 m w.c. G ½” G½” Zone 1 and 2 PP – PP/CF – PVDF
bx81BX81 100 l/min 70 m w.c. G 1″ G ½” Zone 1 and 2 PP – PVDF
bx100BX100 150 l/min 70 m w.c. G 1″ G ½” Zone 1 and 2 PP – PVDF
bx150BX150 220 l/min 70 m w.c. G 1 ¼” G ½” Zone 1 and 2 PP – PVDF
bx251BX251 340 l/min 70 m w.c. G 1 ½” G ½” Zone 1 and 2 PP – PVDF
bx522BX522 650 l/min 70 m w.c. G 2″ G ½” Zone 1 and 2 PP – PVDF
bx503BX503 900 l/min 70 m w.c. G 3″ G ½” Zone 1 and 2 PP – PVDF
All BX pneumatic pumps are operated by a maximum air pressure of 7 bar.

index Catalogue for BX double diaphragm pumps
index Performance curves for BX double diaphragm pumps

Corrosion resistant plastic materials

Selecting the most suitable model for each pump is indeed one of the main skills of Savino Barbera. Our choices
have always been focused on the specific use that our industrial products are intended for. In our air-operated
double diaphragm pumps, all wetted parts (pump boby, balls, diaphragms) are strictly made of corrosion resistant
plastic material and include:

  • Corrosion-resistant plastic materials (PP, PVDF, ECTFE).
  • Chemically inert gaskets (PTFE, EPDM, FPM, NBR).
  • Acid-resistant diaphragms (made of rubber, thermoplastic, PTFE).
  • Balls in PTFE, AISI 316, EPDM, NBR.
  • Ball seats in PP, PVDF, AISI 316, ALU, PE-UHMW, PP-V.

Chemical resistance chart

The type of liquid, the temperature and the work environment are factors to be considered when deciding on the
best choice of construction materials for the pump and its correct chemical compatibility. Some examples are given
in the following table:

30% hydrochloric acid D D B A A A A A
Caustic soda D A A1 A A2 A A A
Dyes B A A
Acetone A A D A A D A D A1
Benzene B B D D D A2 A A D
Ethane A1 A D D A A A
Toluene A A D C D A A C D
Naphtha A A A B D A B A D
Isopropyl alcohol B B B A2 A A2 A
Solvents for paint A A D D D A D D

A= Very good B= Good C= Poor, not suggested D= Severe etching, not recommended
1= Ok up to 22°C (72°F) 2= Ok up to 48°C (120°F) = not available

General information based on fieldwork experience and collected from various sources. We must remember that variables can always occur in the course of industrial processes and can modify the behaviour of the above mentioned materials. Our technical service will confrm the pump-liquid chemical compatibility from time to time, at the time of the offer.

The diaphragms

Diaphragms are the components subjected to the greatest stress during suction and pumping, when they must
also withstand not only the chemical aggression of liquids but their temperature as well. The shape and the profile
of these products provide a greater working surface and improve load redistribution, thus reducing material stress
and yield to a minimum. The possible material configurations are: rubber (NBR, EPDM), thermoplastic (HYTREL, SANTOPRENE) or PTFE.

Rubber diaphragms

They are made from rubber compounds with special additives that improve chemical properties as well as
mechanical bending and strength characteristics. These diaphragms have a nylon backing cloth that improves
stress distribution. Available in:

  • NBR: inexpensive and particularly suited to petroleum- and oil-based liquids.
  • EPDM: good acid, alkaline and abrasion resistance, as well as good flexibility even at low temperatures.

Thermoplastic diaphragms

They are made from thermoplastic polymers that provide high mechanical stress resistance and distribution.
Available in:

  • HYTREL: exceptional strength and elastic return, high resistance to creeping, impact and stress when flexed. With excellent flexibility at low temperatures, while maintaining most of its properties at high temperatures. It is also resistant to the aggression of many industrial chemicals, oils and solvents.
  • SANTOPRENE: excellent acid and alkaline resistance, high flexural strength and good abrasion resistance.

PTFE diaphragms

This material is globally known for its excellent resistance to high temperatures, chemicals and corrosive agents. Our PTFE diaphragms are subjected to a double heat treatment in order to increase elasticity and service life. Each batch undergoes random destructive testing in order to verify its performance.This diaphragm can be fitted together with one of those previously mentioned in order to increase resistance to the liquid’s corrosive chemicals and temperature.

membrane pompe

NBR                               EPDM                              HYTREL                      SANTOPRENE                       PTFE

When to use double diaphragm pumps

Pneumatic diaphragm pumps are generally found to be more efficient pumps in presence of particular liquids (viscous, abrasive, solid-laden, delicate liquids) or with specific service condition such as demanding applications with high humidity or in potentially explosive atmospheres (where ATEX certification is required). Savino Barbera AODD pumps are compliant with ATEX guidelines for safe operation in potentially dangerous or explosive atmospheres (Zone 1 and Zone 2). Multi-purpose pumps to be installed vertically with special bolts on the feet or holes, according the single shape model.

Double diaphragm BX series pumps have specific characteristics as:

  • High suction lift at dry start-up (dry pump).
  • High discahrge head and pulsating fluid flow.
  • Approved for use in flammable. environments and potentially-explosive atmospheres (ATEX Zone 1 & 2).
  • Compact design ideal for reduced industrial spaces.
  • Safe dry operations: ability to run dry without damage.

Double diaphragm BX series pumps are suitable for several uses as the pumping of fluids with the following characteristics:

  • Chemically aggressive.
  • With high apparent viscosity.
  • For food and pharmaceutical applications.
  • Potentially explosive.
  • Solvent-based.
  • For paint industry.
  • Containing suspended solids (Ø max 10 mm).

diaphragm pump for mixing purposes

For mixing aggressive liquids.

pompe montaggio in batteria

For assembling in production line.

pompa a membrana per olio

For pumping industrial oil.

ATEX pumps for explosive areas

BX Series air-powered double diaphragm pumps are intended for use in potentially-explosive athmosferes. Their explosion-proof features are certified in compliance with the 94/9/EC ATEX Directive (Zone 1 and Zone 2). The equipment user is always responsible for classifying its area of use. On the other hand, the manufacturer shall identify and affix the certification class of the manufactured device.


BX pumps Materials Certification class Zone
Non conductive Pumps made of non-conductive plastic or provided with non-conductive centre casing. Metal pumps equipped with non-conductive centre casing. exII 3/3GD IIB T 135°C Zone 2
Conductive Pumps made of conductive plastic (PP with carbon fiber, ECTFE/PVDF with carbon fiber). Pumps made of metal materials (Aluminum, Stainless Steel). exII 2/2GD c IIB T 135°C Zone 1

Meaning of Certification class acronym:

Safety symbols in compliance with DIN 40012 Annex A standard.

II 2/2 GD
Surface equipment for use in Zone 1, where the presence in the air of gases, vapors or mists and combustible dust clouds occurs occasionally during normal running conditions (EN 1127-1 sub-clause 6.3) in both the external and the internal zone.

II 3/3 GD
Surface equipment for use in zone 2, where the presence in the air of gases, vapors or mists and combustible dust clouds unlikely, rarely, or briefly occurs at normal running conditions in both the external and internal zone.

Equipment protected by constructional safety (EN 13463-5).

Exclusion of the following products: Hydrogen, acetylene, carbon disulphide.

T 135°C
Allowed temperature class. The user shall process fluids in compliance with the corresponding temperature classification, bearing in mind manual instructions and provisions of the current legislation. The user shall also consider ignition temperatures of gases, vapors or mists and combustible dust clouds present in the air within the usage area.

Double diaphragm pump options

Savino Barbera AODD pumps can be customized with optional equipment and accessories such as:

  • Air regulator kit (filter, fixing bracket, gauge, 5 m tube and fittings).
  • Pulsation dampener adjusting pressure fluctuations in fluid flow.
  • Single or twin manifolds versions available.
  • 3 suction and delivery port positions.
  • Trolley for portable version (AOD pump is blocked through fixing holes).
  • Flanged connections made of PP, PVDF, ALU, AISI 316 (DN15 → DN80).

Twin suction manifold.


Twin suction and delivery manifold.

Photo gallery of double diaphragm pumps

Photos showing the variety of our BX plastic pumps:

PP and PVDF diaphragm pumps.                   BX30 diaphragm pumps.                    Diaphragm pump under repair.

BX pumps made of PP.                              BX503 diaphragm pumps.                       BX15 diaphragm pump.

Video gallery of diaphragm pumps

Videos showing the technical characteristics of our double diaphragm pumps:

Savino Barbera srl

Via Torino 12
10032 Brandizzo, ITALY
P.IVA 00520820010
R.I.TO 272-1974-2166
REA 489443
Cap. soc. 48000€ i.v.

Tel +39 011 913.90.63

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