Share via email
Some fields are missing
send eMail

Time-Pressure Dosing

How can you increase your sample throughput in the laboratory while also ensuring reliable processes? Pressure/time dosing allows you to dose your samples and reagents precisely while protecting them against the introduction of heat.

Your benefit

  • Expert advice thanks to many years of experience in microfluidic dosing
  • Broad selection of suitable components of the highest quality
  • Precise regulation with high switching frequency
  • Components with long life cycle and excellent cleanability
  • Flexible dosing processes, adapted to your application

In-vitro diagnostics need reliable and cost-effective measurements

Measurement equipment is subject to strict requirements in the analysis of blood and urine samples in in-vitro diagnostics. Be it in the field of haematology, clinical chemistry or immunology, precise and error-free test results are needed, as human lives are often dependent on them. On the other hand, laboratories also face economic challenges, requiring high sample throughputs to be able to operate cost-effectively.

How do you dose very small amounts of fluid quickly and precisely without (cross-)contamination? With its pressure/time dosing solution, Bürkert has addressed your fluidic challenge. 

Your solution: Pressure/time dosing system from Bürkert

Bürkert’s pressure/time dosing system meets your need efficiently: 

  • Precisely reproducible dosing of samples, reagents and cleaning agents
  • Precise results 
  • High sample throughput

The pressure/time dosing system is ideal for in-vitro diagnostics. Precise, error-free dosing is an essential factor in identifying diseases by means of urine analysis or bloodwork, allowing diseases such as leukaemia, cancer of the lymph nodes, anaemia, AIDS or cardiovascular diseases to be reliably diagnosed. Precise pressure/time dosing provides optimum assistance in sample preparation and analysis. 

Diaphragm pump
Ultra-precise pressure controller Type 8763

How pressure/time dosing works

Pressure/time dosing involves the medium being transported from the pressurised container through a valve to the dosing needle. Tank pressure, flow resistance, medium viscosity and medium temperature are precisely controlled. The medium is controlled by opening or closing the valve for a defined length of time in each switching cycle. Transporting the medium using pressure instead of a mechanical pump means that no moving parts can interfere with the medium flow.

Diagramm der Druck-Zeit-Dosierung mit Ventil

Bürkert’s solution satisfies the strictest requirements:

✓ Measures miniscule quantities down to the last μl 
✓ Meets hygiene requirements 
✓ Measures reproducibly by the second 
✓ Media can be changed quickly
✓ Flexibly adjustable dosing volume
✓ High sample throughput for cost-effective work
✓ Preventing uncontrolled heat input to ensure medium remains undamaged


Your benefits: Use pressure to measure more cost-effectively

Two factors in particular contribute to your laboratory’s success: A high sample throughput rate and reliable dosing processes. 

✓ Pressure/time dosing has a speed advantage
The tank is pressurised, making the reagent available at all times. When the valve opens, the device commences dosing without a time delay.

✓ Pressure/time dosing has a reliability advantage:
In a system solution all key components fit together like parts of a puzzle. Low production tolerances ensure that all valves switch consistently – even after replacement.

Two more reasons why Bürkert’s system solution is ideal for you: 

1. Bürkert’s valve technology makes the difference

Diagramm zeigt Schaltgeschwindigkeit des Ventils bei verschiedenen Drücken.

Regardless of the pressure used to dose a liquid, the valve opens and closes almost always at the same speed. This allows pressures to be increased or decreased arbitrarily – your valve will continue to work consistently fast and precisely. As the test of the Type 6650 shows, valve always switches after 5ms at each pressure.

2. Preventing heat input, protecting media

In addition, the design of the valve prevents uncontrolled heat input into the medium and helps to achieve accurate test results. 

Blood and urine samples contain proteins that are destroyed at temperatures of 41°C or above. For your dosing process, this makes it necessary to minimise heat input.

Bürkert valves keep heat out reliably:
✓ With low heat absorption
✓ With optimum thermal management

The Whisper Valve Type 6724 is an example of how uncontrolled heat input in the medium can be avoided.

Under the following conditions, we have measured the following in the fluid chamber: Standalone device, coil up, ambient temperature of 21°C, 100 % duty cycle, 26.4 V (10 % overvoltage).

The result of the test: When the medium is stationary the heat input into the medium is 9°C at maximum. The temperature in the fluid chamber is therefore no more than 30°C. This successfully prevents the proteins from being destroyed by temperatures of 41°C or more.

Normally there is a certain amount of flow when the device is switched on, which causes the temperature to drop substantially – this results in virtually no heating during normal operation.

During fluid flows the heat input into the medium caused by the valve is barely measurable:

Graph zeigt die Temperatur, die durch das Ventil Typ 6724 in das Medium abgegeben wird, in Relation zu verschiedenen Durchflusswerten. Bei steigendem Durchfluss ist der Wärmeeintrag in das Medium fast nicht messbar.

Our expertise: Fast, precise and systematic dosing

You want to speed up the dosing process? You want your analysis device to work more cost-effectively? In both cases, our components and system solutions provide you with support for pressure/time dosing:

Tailored solutions for your fluidic challenges

Bürkert is ready to assist you, and not just with well-conceived components. We also develop tailored system solutions for your equipment – with highly qualified engineers and the best production facilities in our Systemhäuser. There, we combine ideas, development, serial concepts, test laboratories and production under one roof. Speak to us about your specific solution needs.


Our products for your pressure/time dosing

Type 6650

2/2 way Flipper-Solenoid Valve with separating diaphragm

Type 6650
  • Only 4.5 mm wide
  • Medium isolation, for aggressive fluids
  • Direct-acting
  • Vacuum up to 7 bar
  • Short response times

Type 6712

2/2-way Whisper Valve with media separation

Type 6712
  • Highest chemical resistance combined with minimum internal volume
  • Compact design with 7 mm installation width
  • DN 0.8 mm (3 bar) and 0.4 mm (5 bar)
  • Switching noise < 36 dB
  • For dosing applications with excellent cleanability

Type 6724

2/2 or 3/2-way Whisper Valve with media separation

Type 6724
  • Highest chemical resistance
  • Compact design with 8.9 mm installation width
  • DN 0.8 mm (vacuum up to 5 bar) and 1.2 mm (vacuum up to 3 bar)
  • Very fast, almost silent switching with < 20 dB (A) and very low power consumption
  • High back-pressure tightness, excellent cleanability and 100% duty cycle

Type 6144

3/2-way flipper solenoid valve, direct-acting

Type 6144
  • Direct-acting
  • 0 to 10 bar
  • Low power consumption
  • Standard, Ex ia version
  • 10 mm installation width / 11 mm width/station

Type 7615

Micro Dosing Unit for precise dosing in microlitre-range

Type 7615
  • Diaphragm pump for high chemical resistance
  • Dosing volume 5 µl/stroke up to 8 ml/min. in both directions
  • Dosing accuracy < +/- 3,5 %
  • Self priming
  • Integrated electronics, easy to use

Type 8763

Pressure controller for precise time-pressure dosing

Type 8763
  • Repeatable and accurate dosing of liquids in the µl range
  • Response time in milliseconds and active pressure relief for optimum control performance
  • Digital communication for easy integration into your fieldbus network
  • Extended functionality through additional sensor input + actuator output e.g. for pump or additional pressure sensor
  • Active vent valve to minimize consumption of costly carrier gas

You want to precisely measure reagents and samples and receive perfect measurement results quickly? If so, get in touch with us.


Our solutions for other dosing principles: