Effective vacuum equipment is essential in any fully equipped laboratory bench from high school and college through to the most advanced research institutions working on cutting-edge science. In every case, this equipment should be sized to meet your highest levels of demand while providing cost-effective operation at low or average use levels.
Determining the right size pump can be complex in large central vacuum systems serving tens or hundreds of bench stations across multiple laboratories. Multi-pump installations need to deliver enough redundant capacity to manage a partial or complete shutdown of one or more units, as well as continuous pressure loss through system leaks and open connections.
In this blog, we examine some of the most important considerations that go into how to size a laboratory vacuum pump. We’ll look at:
- Why proper sizing is important
- Becker pumps vacuum suitable for laboratory use
- How to calculate your vacuum pump requirements
- Common sizing mistakes to avoid
- Why it makes sense to choose Becker for your vacuum pump needs
WHY IS PROPER PUMP SIZING IMPORTANT?
Ensuring properly sized, scalable vacuum pump capacity for your laboratory is not just about maximizing your organization’s investment in equipment and overhead expenditure. Incorrect or inconsistent pressure affects your vacuum system’s ability to reach and maintain the desired levels and flow rates, potentially affecting the quality of work in your laboratory.
- An oversized pump can lead to poorly controlled evacuation. This can damage equipment or cause materials to outgas, releasing unwanted water vapor or gasses. In addition to the above, excess energy is being wasted.
- An undersized pump might struggle to reach and maintain the necessary vacuum, delaying processes or making it hard to create standardized conditions. This can also damage any vacuum pump operating below the proper vacuum level.
FACTORS TO CONSIDER WHEN SIZING A PUMP
Several interrelated factors must be considered when determining the overall pumping capacity and individual pump sizes that your laboratory application requires.
These include:
Desired vacuum level: How much vacuum is required by your application? Do you require low levels of vacuum to encourage flow or evacuate small containers, or does your application need a sustained, very low atmosphere environment?
Flow rate: How quickly do you need your pump to reach the required vacuum level? Determining how much gas your pump will need to remove in a set time depends on the vacuum level required and the size of the containers or chamber that typically needs to be evacuated. Site elevation should be considered. Higher elevations will have reduced capacity and might need to be sized to the next size larger pump(s).
Single-use or centralized system: Are you depressurizing a single application, or a facility-wide system serving multiple general-use bench stations? What is the range of pressure required across multiple stations?
Redundancy requirements: How much extra capacity do you need to build into your system to accommodate unexpected spikes in demand, general leakage from plumbing and fittings across your entire system, or failure or downtime of one or more pumps in your array?
Energy use and sustainability: What targets do you need your equipment to meet in terms of rated horsepower to achieve energy efficiency targets? Does your company need to meet carbon emission goals or other sustainability benchmarks?
Service factor: How often will you be running the system at peak demand or is this for intermittent usage? Will each point of use be running at the same time or just a percentage of them?
THE BEST BECKER PUMPS FOR LABS
Becker Pumps is a leading global supplier of high-quality vacuum pumping equipment. For laboratory vacuum use we typically recommend our efficient oil-sealed pumps, which are most resistant to gasses that might be ingested during evacuation. We also recommend that all our pumps be used with vapor condensation filters to prevent this.
Our Advantage-P Oil-Flooded Central Vacuum Systems are made specifically for medical and laboratory use, and feature:
- Tank-mounted or modular/expandable arrangements
- Field expandable up to six pumps
- Automatic alternating and cascading controls
- Flow capacities from 18 to over 2,600 SCFM
All Advantage-P vacuum systems also include our automatic purge system. This allows the unit’s pumps to purge any remaining gasses from the pump, helping to prevent corrosion and enhance safety.
Advantage-P systems employ our high-efficiency U-Series oil-flooded pumps for laboratory applications that demand vacuum levels up to 0.075 Torr.
The following Advantage-P duplex models are available:
| Model | Flow (SCFM) | Power (HP) | Tank (Gal.) | Tank Orientation | ||
|---|---|---|---|---|---|---|
| 0 Torr | 0.038 Torr | 0.063 Torr | ||||
| DT10P-V | 7.1 | 2.4 | 1.0 | 0.6 | 60 | Vert. |
| DT16P-V | 11.2 | 3.63 | 1.44 | 0.9 | 60 | Vert. |
| DT21P3 | 16 | 4.96 | 2.02 | 1.2 | 60 | Horiz. |
| DT21P-V | 16 | 4.96 | 2.02 | 1.2 | 60 | Vert. |
| DT40P3 | 28.8 | 10.5 | 3.19 | 2.4 | 60 | Horiz. |
| DT40P-V | 28 | 10.5 | 5.7 | 2.4 | 60 | Vert. |
| DT70P3 | 49 | 17.8 | 6.04 | 3 | 120 | Horiz. |
| DT70P-V | 49.4 | 17.8 | 9.6 | 3 | 120 | Vert. |
| DT100P3 | 71 | 25.8 | 9.17 | 5 | 120 | Horiz. |
| DT165P3 | 116 | 36.8 | 14.95 | 6.4 | 120 | Horiz. |
| DT200P3 | 141 | 44 | 17.88 | 8.9 | 120 | Horiz. |
| DT300 | 211 | 64 | 24.44 | 12.1 | 240 | Horiz. |
Smaller (Simplex) horizontal and vertical tank versions and larger (Expandable Duplex, Triplex, and Expandable Quadruplex) horizontal tank versions are available.
Dry rotor pumps, hook and claw, and dry screw pumps may also be used to meet special conditions or application requirements, such as lower vacuum needs.
SIZING A LABORATORY VACUUM PUMP
To start, identify whether you are sizing a lab system to supply vacuum throughout a facility via a centralized system or for a single application within the laboratory. For most centralized systems, we recommend you use the following procedure:
- Estimate the system-wide flow in square cubic feet per minute (SCFM) based on a standardized pressure of 25” Hg. To do this, count the number of connections throughout your facility.
- Apply a standardized flow rate per terminal of 0.5 SCFM to calculate the use factor, or remaining pressure on each lateral line when all terminals are in full use. The following table may help:
| No. of Terminals | Use Factor |
| 1-5 | 100% |
| 6-8 | 90% |
| 9-12 | 80% |
| 13-20 | 70% |
| 21-35 | 60% |
| 36-80 | 50% |
| 81-160 | 40% |
| 161-280 | 35% |
| 281-500 | 30% |
| 501-1000 | 25% |
| 1001-2200 | 20% |
| 2201-5000 | 15% |
| 5000 + | 10% |
- Use the following equation to calculate the SCFM required per lateral:
| Required flow = [No. of terminals on lateral] x [SCFM flow per terminal] x [Use factor/100] |
- Then add together the total for all laterals on your system to get the total SCFM flow required at 25” Hg.
- Refer to the flow figures listed on the vacuum pump specs sheet to identify the model that best meets your capacity.
The process for identifying a single-point use simply involves matching the required flow and vacuum level of the application with an appropriately sized pump.
ADDING IN REDUNDANCY
In addition to the actual flow rate your single point or centralized system requires, there are some reasons why you might want to build in a redundancy factor into the flow rate figure you arrive at:
Leakage: No system is perfectly airtight. You should expect your system to lose pressure through loose fittings and open connections.
Pump failure or downtime: Consider installing a pump model with two or more vacuum pump units so pressure can be maintained if one or more units go offline.
Future expansions: If it’s likely you will expand your facilities or add in more vacuum points, consider incorporating extra capacity so your system can scale when the time comes.
LOOKING BEYOND FLOW
While determining flow is critical to the correct sizing of a laboratory vacuum pump, there are other factors to consider that might affect your final choice of pump size.
PLUMBING
The quality of your plumbing is also significant, even if it is only serving a single application. Leaking pipes will increase your flow requirements and make your pump work harder to maintain pressure, but very narrow plumbing will also significantly affect the efficiency of your pump.
APPLICATION
It’s also possible that specialized lab requirements will also affect your pump sizing decision. In addition to having to depressurize large chambers, your pump may need to exhibit specialized pump-down control to avoid degassing and potentially damaging porous materials.
Again, a close look at the power curves of the pumps on your shortlist will provide a guide to how well each performs under pressure.
COST EFFICIENCY
Laboratory requirements being equal, you might choose to go with a smaller horsepower pump than that indicated by your calculations to save on energy costs. You might also opt for a more efficient oil-sealed vacuum pump over effective but more power-hungry hook and claw options.
SCALING FOR GROWTH
Does your company or institution plan to expand operations in the coming years or overhaul existing facilities? If you are replacing a vacuum pump now it might help to plan for a future with expanded demands, including more laterals and, ideally, upgraded plumbing infrastructure.
SAFETY FIRST
Most importantly, check that your vacuum pump decisions ensure the highest safety standards. In particular, laboratory vacuum pumps must be able to safely evacuate flammable, corrosive, and hazardous materials.
Oil-sealed pumps are better at handling any gasses that leak through to the pump chamber itself, but be sure that your setup also includes a vapor-condensing filter immediately upstream of the pump.
SIZE IT RIGHT. MAKE IT BECKER.
Finding the right pump for your laboratory vacuum requirements is a complex decision that’s about a lot more than raw horsepower. It’s important to work with an experienced, reputable, equipment supplier to ensure you invest in the right equipment for the job.
Becker is a leading supplier of quality vacuum pumps to laboratories of all kinds worldwide. Researchers, administrators, and facility managers trust Becker to deliver powerful, reliable, and safe pumping solutions right-sized to their specific vacuum needs.
Becker offers the widest range of vacuum pumping solutions designed specifically for medical and laboratory use and includes our leading sealed oil, dry vane, hook and claw, and dry screw technology pumps and our purpose-built Advantage L pump-tank solutions.
Talk to us about your laboratory vacuum needs. We’ll help you find a safe, reliable, and cost-effective solution that helps produce results for your people today and delivers long-term returns on your investment.
