For instance, positive displacement pumps, such as lobe or 3 phase diaphragm pumps, are popular in the biopharma and food industries for product transfer and chemical additives. The nature of these pumps, moving a specified volume of fluid for each stroke, typically results in downstream pulsation causing disruptions for the next process. In particular, biopharmaceutical filtration and chromatography are easily disrupted when fluid is delivered in pulses. The sensitive resins in the chromatography column can be significantly disturbed due to these pulsations, which can be damaging to the final product. Due to the high costs of biological material, any disruption in the delivery lines is undesirable.
Equilibar pulsation dampening solutions
Upstream pulsation dampening is a natural behavior of the Equilibar® valve because the upper diaphragm naturally responds to slugs of fluid moving through the valve, keeping upstream pressure constant. The ultra-wide Cv range of the Equilibar valve allows it to keep up with positive displacement pumps to maintain consistent upstream pressure.
The Equilibar FD sanitary fluid control valves can also help reduce downstream pulsations. FD valves include a unique passive dampening design as standard, and now they have a new active dampening system upgrade option which offers the same precision control across a wide range of flow rates as the original design with the benefits of increased pulsation dampening.
The easiest way to identify pulsations in a system is to evaluate a system’s pressure profile. Below is a plot of actual pressure data downstream of a common 3 phase diaphragm pump set to 30 Hz. This snapshot shows approximately 4 seconds of a typical downstream pressure profile at the pump outlet at steady state conditions. The plot compares pressure profiles under three different conditions:
- Grey line: Pump ONLY
- Red line: An Equilibar FDO6 (with passive dampening design)
- Black line: An Equilibar FDO6 with optional active pulsation dampening system
The passive pulsation dampening* comes from a special insert below the lower diaphragm that absorbs energy through the natural compression of the material. The insert has a unique geometric pattern to allow ample compression while also providing uniform pressure to the underside of the lower diaphragm to maximize its sensitivity. The insert is standard in the Equilibar FDO valve and reduces pulsation amplitude an average of 25%.
The active pulsation dampening system* uses the reference pressure supply gas to maintain a pressurized lower diaphragm. This unique technology will create an equilibrium with the wetted system pressure, maintaining a zero pressure differential across the lower dampening diaphragm, even as the system pressure changes over time. For instance, if the downstream pressure of the process increases by 10 psi over the course of the “run,” the dampening system will self-adjust to provide continuous optimal dampening without user interaction. This configuration requires a modified bottom cap and reduces downstream pulsation an average of 50%. At steady state conditions, the active solution typically consumes 200 ml/min of air and can be configured to consume less if desired.
Please contact an Equilibar application engineer for more information.
This graph shows the amplitude of the pressure profile under the same three conditions.