Oil-less design with a chemically resistant PTFE diaphragm, so process media don’t touch metal. Suited to semiconductor R&D labs, chemical analysis sample preparation, filtration suction and as a vacuum source for rotary evaporators.
A laboratory diaphragm pump is a low-flow pump for lab evacuation, filtration suction and moving corrosive media. A motor drives a connecting rod that moves a PTFE or EPDM diaphragm back and forth, with inlet and outlet check valves to draw gas or push liquid. Its main features are “oil-less + corrosion-resistant + media don’t touch metal,” making it basic equipment in chemical analysis, semiconductor R&D and biotech labs.
The model on this page is the N96KTDC-B-M laboratory diaphragm pump (for gases and vapors only). A JIAHON affiliated company supplies customers throughout Taiwan.
Specifications (maker specifications for N96KTDC-B-M)
| Item | Specification |
|---|---|
| Pump type | Oil-less diaphragm pump |
| Pumping speed | 7.0 L/min (±10%) |
| Ultimate vacuum | < 130 mbar (absolute) |
| Maximum operating pressure | 2.5 bar (gauge) |
| Diaphragm material | PTFE-coated diaphragm (KT version) |
| Wetted materials | PPS pump head, PTFE-coated diaphragm, FKM valves (KT version) |
| Ports | G 1/8 female thread |
| Weight | 0.6 kg |
| Power | 24 V DC brushless motor, 19 W, 0.9 A |
| Media | Gases and vapors only (the maker advises against pumping liquids) |
Applications
Laboratory diaphragm pumps are a common vacuum source and transfer device in chemistry, biotech and semiconductor R&D labs. Four common uses:
1. Vacuum source for rotary evaporators
Organic synthesis, sample concentration and solvent recovery all use rotary evaporators to evaporate under reduced pressure. A diaphragm pump connected after the evaporator’s condenser gives 100–200 mbar vacuum, lowering solvent boiling points to speed evaporation, without oil contaminating samples. Use a condenser to keep solvent out of the pump.
2. Filtration suction (filtration / SPE)
Sample preparation filtration and solid-phase extraction (SPE) need continuous vacuum. Connected to an SPE vacuum manifold or the top of a filter flask, a diaphragm pump gives about −0.8 bar vacuum to draw samples through filter membranes or SPE columns — used in chemical analysis, pharmaceuticals and semiconductor process liquid QC.
3. Moving corrosive gases and chemicals
Gas sampling (ambient air, exhaust analysis) and automatic chemical dosing need pumps where media “don’t touch metal.” Diaphragm pumps with all-PTFE / PVDF wetted parts can move corrosive gases such as HCl, HF and NH₃ and acid rain samples without contaminating them (the N96KTDC-B-M on this page is for gases and vapors only, not liquids). Common in semiconductor fab exhaust monitoring.
4. Supporting vacuum ovens and lyophilizers
Vacuum drying ovens and small lyophilizers need a matching vacuum pump. As a “primary vacuum source,” a diaphragm pump reaching 100 mbar meets sample drying needs; it is quiet, has no oil contamination and needs no periodic oil changes, a common choice in R&D labs.
Selection points
| Item | Recommendation | Note |
|---|---|---|
| Pumping speed | Rotary evaporator 30–40 L/min, SPE 20–30 L/min, vacuum oven 50–60 L/min | Too little flow slows evaporation or filtration |
| Vacuum level | 100–200 mbar for general use; deep vacuum needs multi-stage pumps, 2–8 mbar | High vacuum needs rotary vane + turbomolecular pumps |
| Diaphragm material | PTFE for strong acids and alkalis, EPDM for general aqueous solutions, FDA silicone for biotech | The wrong material greatly shortens life |
| Safety rating | ATEX / Ex certification for flammable solvents (ether, n-hexane) | Recommended for organic synthesis labs |
| Noise | < 55 dB for lab work areas | Long running affects operators |
| Spares | One diaphragm kit and one valve kit | Allows in-house repair without downtime |
Diaphragm vs oil rotary vane vs vane vs peristaltic pumps
| Pump type | Vacuum | Corrosion resistance | Sample contamination | Use |
|---|---|---|---|---|
| Diaphragm pump | 2–200 mbar | High (all PTFE / PVDF) | No oil, no contamination | Lab vacuum, chemical transfer |
| Oil rotary vane pump | 0.001–1 mbar | Low (chemicals degrade the oil) | Risk of oil mist contamination | High vacuum where oil is acceptable |
| Vane pump | Not recommended for vacuum | Low | Needs lubricating oil | Positive-pressure water, non-corrosive |
| Peristaltic pump | Not recommended for vacuum | High (tubing, no metal) | No metal contact | Sterile, ultrapure water, biotech |
In practice: most lab uses (rotary evaporators, SPE, filtration, sampling) are well served by a diaphragm pump; only high vacuum (< 10⁻³ mbar) needs oil-sealed or turbomolecular pumps, and continuous sterile liquid transfer uses peristaltic pumps.
Reading diaphragm life and spares strategy
| Check | Normal | Replace |
|---|---|---|
| Suction / vacuum | Reached | Down 20% or more |
| Running sound | Smooth and quiet | Abnormal noise, more vibration |
| Appearance | No leaks, no mist | Leaking pump body, mist at outlet |
| Flow stability | Stable | Fluctuating, unstable |
Spares strategy:
- Heavily used labs (24-hour running): keep one diaphragm kit + one valve kit.
- Chemical transfer (strongly corrosive): keep 2 sets.
- Labs with occasional use: order when needed.
- Diaphragm pump makers usually offer a “Service Kit” (diaphragm + valves + O-rings).
Selection: six items of information at once
| Item | Description | Example |
|---|---|---|
| 1. Application | Main use of the pump | Rotary evaporator / SPE / sampling |
| 2. Media list | Liquids and gases it will contact | Water, ethanol, HCl, NH₃ |
| 3. Pumping speed | Flow needed per minute | 30 L/min |
| 4. Vacuum | Lowest absolute pressure needed | 100 mbar |
| 5. Explosion protection | Flammable solvent environment or not | ATEX / Ex certification needed |
| 6. Noise | Environmental requirement | < 55 dB |
The model on this page is the N96KTDC-B-M; models for other flow, vacuum or explosion-protection needs are available on request.
Common questions
Can the N96KTDC-B-M pump liquids? No. It is for gases and vapors only; the maker advises against pumping liquids.
Trademarks: KNF and the model name on this page are trademarks or model names of their owner, used here only to identify the product. JIAHON is not the authorized distributor of KNF in Taiwan.
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