Diaphragm pumps
Diaphragm pumps from VACUUBRAND are the ideal vacuum technology for many laboratory and industrial applications. Important advantages include oil-free operation, smooth running, low maintenance and a very long service life.
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Diaphragm pumps – Benefits at a glance
Thanks to their oil-free operation, chemical resistance and unsurpassed long-term performance, diaphragm pumps are often the first choice for laboratory and industry applications in the rough vacuum range down to 1 mbar. They are also ideal as a clean backing pump for turbomolecular pumps or for integration in devices, e.g. in analytics.
Oil-free operation
Thanks to their dry and completely oil-free operation, diaphragm pumps are ideal for clean processes and the production of pure products. There is no waste oil or waste water. Diaphragm pumps are therefore also particularly low-maintenance and environmentally friendly.
Durable – even in the case of aggressive chemicals
VACUUBRAND diaphragm pumps are known for unsurpassed reliability over many years. Chemistry diaphragm pumps represent uncompromising chemical resistance. Thanks to high-quality materials, precise manufacturing processes, and 100% quality control, VACUUBRAND diaphragm pumps guarantee long service intervals, and longstanding reliability.
Efficient VARIO® control
Precise, efficient and quiet – VARIO® diaphragm pumps control the vacuum according to need via the motor speed. This makes the pump whisper-quiet, reduces energy consumption and vibration and extends the service life of the diaphragms. In combination with the VACUU·SELECT® controller, they achieve the optimal conditions for reproducible processes
Typical Applications
Diaphragm pumps are often the first choice for laboratory and industry applications in the rough vacuum range down to 1 mbar. Chemistry diaphragm pumps are perfect in the case of aggressive chemicals.
Choosing a diaphragm pump type
Depending on the requirements of the media being handled, VACUUBRAND offers a range of options: chemistry diaphragm pumps for aggressive media, diaphragm pumps for non-corrosive media, and ATEX chemistry diaphragm pumps for potentially explosive atmospheres.
Chemistry diaphragm pumps
VACUUBRAND chemistry diaphragm pumps represent uncompromising chemical resistance - even in the case of aggressive chemicals. To achieve this, we use carefully selected materials. They also provide excellent condensate compatibility.
Diaphragm pumps for non-corrosive media
Thanks to their oil-free operation and unsurpassed long-term performance, diaphragm pumps are often the first choice for laboratory and industry applications. They are also ideal as a clean backing pump for turbomolecular pumps.
ATEX diaphragm pumps
ATEX pumps are equipped with additional safety features against sources of ignition. The ATEX approval includes the inside of the pump (pumped gases and vapors) as well as the pump environment (installation location).
Ultimate vacuum and pumping speed of a diaphragm pump
A vacuum pump is characterized by two key parameters: The lowest achievable pressure – also called ultimate vacuum – and the pumping speed. VACUUBRAND offers a huge selection of diaphragm pumps with ultimate vacuums ranging from 100 to 0.3 mbar and pumping speeds from 0.7 to 20 m³/h. With the VAC 24seven series up to 6 pumps can be combined modularly to one system and thus achieve a pumping speed of up to 120 m3/h.
The pumping speed curve
The pumping speed varies with the pressure and decreases in the direction of the ultimate vacuum. Particularly in the process pressure range, the vacuum pump must provide sufficient power to compensate for potential system leakage in addition to the actual process requirements. Otherwise, the maximum achievable ultimate vacuum can deviate significantly from the technical specifications. It is therefore worthwhile for the user to take a look at the pumping speed curve. This shows the pumping speed as a function of pressure. The shape of this curve makes it easy to recognize how powerful the pump is in the area of the desired process vacuum.
Consultation – how to pick the right pump model
Selecting the right diaphragm pump depends on various factors and is not a trivial task. Our experts are happy to assist you in choosing the right pump for your specific requirements. Our Vacuum Pump Selection Guide is a helpful tool for obtaining suitable product recommendations tailored to your needs.
Vacuum Pump
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VAC 24seven - Pumping speed up to 120 m³/h
With the VAC 24seven series, the advantages of chemistry diaphragm pumps are also available on a pilot and pilot plant scale. Up to 6 pumps are combined modularly to form powerful process vacuum system.
OEM and built-in solutions
VACUUBRAND diaphragm pumps are adaptable to your installation requirements: Label and color design, connections, drives and much more can be changed in the OEM variants by arrangement. VACUUBRAND has been a trusted partner for OEM solutions in the laboratory, analytical and industrial sectors for over 50 years.
Vacuum control for diaphragm pumps
Classic 2-point control uses a solenoid valve with a vacuum controller. Advanced VARIO control achieves unparalleled precision and efficiency with motor speed control. VACUUBRAND diaphragm pumps are available with integrated VACUU·SELECT controller or without for use on systems with existing vacuum control.
VARIO® diaphragm pumps
Precise, efficient and quiet – VARIO® diaphragm pumps control the vacuum according to need via the motor speed. In combination with the VACUU·SELECT® controller, they achieve the optimal conditions for reproducible processes. The corresponding interfaces enable integration in modern laboratory networks.
2-point vacuum valve control
Classic 2-point control uses a solenoid valve with a vacuum controller to maintain process control. You can use our VACUU·SELECT controller or an existing vacuum controller for your diaphragm pumps. We also offer chemistry diaphragm pumps with integrated VACUU·SELECT controller. With PC 520 select and PC 620 select it is even possible to control two different vacuum processes in parallel with just one VACUU·SELECT. In this case, a separate solenoid valve and vacuum sensor are installed for each process .
VACUU·SELECT vacuum controller
Diaphragm pumps without integrated vacuum controller are always suitable for use on systems with existing vacuum control. Our VACUU·SELECT complete controller is a fully equipped vacuum controller for existing vacuum sources such as single pumps or powerful vacuum networks. The controller is available in several mounting configurations, as a benchtop device, for scaffold mounting or as a built-in version for panel mounting.
Useful accessories for diaphragm pumps
Inlet separator and emission condenser
Inlet separator (AK) catches liquid and physical material (condensate or particles) from the suction flow at the inlet of the pump. The pressure-side emission condenser (EK) enables nearly 100% solvent recovery. The Peltronic emission condenser performs condensation of solvent vapors without external coolant such as water or dry ice. It works electronically and uses Peltier elements as cooling system.
Vacuum gauges & regulator valves
Vacuum gauges from VACUUBRAND offer high measuring accuracy for precise measurements. We only choose chemically resistant and robust sensors for our vacuum gauges: For the typical application range from atmospheric pressure down to 1 mbar we use ceramic diaphragm sensors, and in the range below 1 mbar down to 10-3 mbar, we use ceramic-jacketed Pirani sensors. For some processes like simple filtration an electronic vacuum controller or gauge is not required. A manual regulator valve with manometer can still be helpful for example to maintain a defined flow or drip speed. These are available as accessories for diaphragm pumps.
Hoses and connection parts
The right connection elements and a connection which is as leakage-free as possible are important for achieving the indicated pump specifications. Use a suitable vacuum hose which offers adequate stability and does not become porous. The hose should be as short as possible and have the maximum cross-section possible. The selection of connection elements depends on your pump model and the vacuum connection of the application. For cases in which the connection sizes of the pump and the application differ, we offer suitable adapters as accessories. In our Connection Guide you will find everything you need to know about connecting your vacuum pump to your application.
Diaphragm pump technology explained
How it works
In a diaphragm pump, one or more diaphragms are moved up and down so that the pump chamber increases and decreases in volume, creating a pumping effect. The diaphragm hermetically (airtight) seals the pump chamber, in which the gases and vapors are sucked in and compressed, from the drive with the motor. The pump chamber is therefore completely dry (no operating fluids / lubricants) and the pumped gases are not contaminated. Two mechanical valves ensure that extracted gas is aspirated from the correct tube and then ejected into the other. This ensures the flow of gas from the application through the pump towards the exhaust.
Chemical resistance and durability
The assembly of mechanical components around the individual pump chamber through which the media is pumped is called the pump head. It is crucial that the materials used in the pump head are chemically resistant. Special fluoroplastics with high long-term stability and impermeability are used to manufacture different parts in the pump head. Although fluoroplastics are extremely chemically resistant, they are not very mechanically stable, which is why a metallic stability core inside is extremely important.
Single-stage and multi-stage diaphragm pumps
The ultimate vacuum and the pumping speed of a pump depend on the modular connection of the cylinders. Connecting cylinders in parallel increases the pumping speed, while connecting them in series results in a better vacuum – i.e. lower ultimate pressure. VACUUBRAND connects up to four stages in series in its diaphragm pumps and achieves ultimate vacuums between 100 mbar (single-stage) and 0.3 mbar (four-stage). The pumping speed of diaphragm pumps is influenced by the parallel connection of the cylinders as well as the number of cylinders and the volume of the pump chamber.
Operation and maintenance – frequent questions
The right connection elements and a connection which is as leakage-free as possible are important for achieving the indicated pump specifications. Use a suitable vacuum hose which offers adequate stability and does not become porous. The hose should be as short as possible and have the maximum cross-section possible. The selection of connection elements depends on your pump model and the vacuum connection of the application. We would be happy to advise you in this regard.
Condensation inside the pump impairs its function and performance and can eventually lead to damage. This problem affects both diaphragm and rotary vane pumps. Many pumps therefore have what is referred to as a gas ballast, which lets in small amounts of air or inert gas to the pump through a valve to minimizes the condensation of gases inside the pump. For many applications in chemistry, this function is indispensable for maintaining performance specifications as well as for the protection of the pump. For self-cleaning, the pump should be left to run for 15-30 minutes with the gas ballast valve open and/or the inlet open.
No, a diaphragm pump does not need any warm-up phase. However, for self-cleaning, the pump should be left to run for 15-30 minutes with the gas ballast valve open and/or the inlet open. Any condensate will be removed as a result.
We have subjected our diaphragm pumps to multi-year performance tests and determined a typical diaphragm service life of 15,000 operating hours. The parts subject to wear should be replaced after this period of time or no later than when vacuum values decrease. With VARIO control, the motor speed is adjusted based on need. As a result, maintenance intervals can be significantly increased even further.
Check the hoses and connectors for leaks. Another reason may be the formation of condensate in the pump chamber. It is therefore important to use the gas ballast when working with condensible media and to allow the pump to run for 15-30 minutes after operation. Decreasing vacuum values may also be an indication that parts subject to wear need to be changed. If this does not solve the problem, contact our Service Department. We would be happy to help you!
Contact ServiceCheck the in-line suction valve. The seal may be dirty or worn. If this does not correct the problem, contact our service department. We would be happy to help you!
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Oil-free diaphragm pumps at the Ruhr University Bochum
They eliminate 99,9 % of the unwanted gases in procedures such as molecular beam epitaxy (MBE) and focused ion beam implantation (FIB): oil-free diaphragm pumps from VACUUBRAND run continuously as fore pumps at the Ruhr University Bochum. The fore vacuum supports the generation of high and ultra-high vacuum. In this interview, we talk to Professor…
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