Specifications

Component List

All components listed below are included in this kit. Items marked Optional can be customized.

Component	Standard Spec	Upgrade Options	Qty	Link
Please contact us to confirm the available specifications.

📌 Customization Notes:
• Filter flask capacity: 500ml, 1000ml (standard), 2000ml, 5000ml — choose based on volume
• Funnel options: Buchner (standard) or Sintered (for strong acids/bases)
• Vacuum pump: Diaphragm (standard), Water aspirator, Rotary vane
• Mix and match — no minimum order quantity
• Special requirements? Just ask our technical team

💡 Recommended Add-Ons: Filter paper (for Buchner funnel) · Membranes (0.45μm/0.22μm) · Spare tubing · Vacuum grease

Product Description

I. How It Works

Vacuum filtration is simple: a vacuum pump removes air from the filter flask, creating a pressure differential across the filter paper — atmospheric pressure pushes the liquid through, and solids stay on top. Compared to gravity filtration, it's several times faster — what used to take ten minutes now takes seconds.

This technique is typically used when you need to collect the solid — crystals, precipitates, catalysts — dry and weigh them right after filtration. If your target is in the liquid (you need the filtrate), gravity filtration is the better choice.

✦ Vacuum vs Gravity Filtration:

Vacuum Filtration: Vacuum-driven, fast — best for collecting solids (precipitates, crystals).
Gravity Filtration: Gravity-driven, slower — best for collecting the filtrate (target in solution).
Bottom line: Need the solid, need speed → Vacuum filtration. Need the liquid → Gravity filtration.

II. What's in the Setup

The apparatus consists of four main components:

Buchner Funnel (or Sintered Funnel) — Core filtration component; cylindrical body with a perforated plate for filter paper
Filter Flask (Suction Flask) — Heavy-wall conical flask with a side arm for vacuum connection
Safety Trap (Buffer Flask) — Prevents suck-back, protects the vacuum pump
Vacuum Pump — Provides negative pressure; options include diaphragm, water aspirator, or rotary vane pumps
Heavy-Wall Vacuum Tubing — Connects components; standard tubing will collapse under vacuum

III. Choosing the Right Funnel

Buchner Funnel — Most common; suitable for most solid-liquid separations; uses filter paper
Sintered Glass Funnel — Fused glass frit, no filter paper needed; suitable for strong acids and bases
Glass Fiber Funnel — Heat and corrosion resistant; suitable for hot filtration and special samples

When using a Buchner funnel, cut the filter paper slightly smaller than the funnel inner diameter, but make sure all the holes are covered.

IV. Material & Workmanship

The filter flask and funnel are made from borosilicate glass 3.3 with heavy-wall construction to withstand vacuum. The Buchner funnel has a uniform perforated plate for good filter paper contact. The safety trap is critical — if something goes wrong or power fails, it catches back-flowing water before it can contaminate your sample.

Manufactured to industry standards — you can count on it.

Applications

Typical Applications

Crystal Collection

Rapid separation of crystals after recrystallization — dry and weigh directly

Catalyst Recovery

Recovering solid catalysts after reactions

Hot Filtration in Recrystallization

Removing insoluble impurities from hot solutions

Environmental Monitoring

Suspended solids (SS) determination — filter through 0.45μm membrane, dry, and weigh

Microbiology Sample Prep

Pre-filtration to remove large particles

Pharmaceutical Decolorization

Activated carbon removal

Suitable Conditions

Your target is the solid precipitate or crystals (you're collecting the solid)
Particles are not too fine — gelatinous precipitates and ultra-fine particles are not suitable
You need speed — you don't want to wait
Not suitable if you only need the filtrate (use gravity filtration for that)

Volume	Filter Flask	Buchner Funnel	Best For
Please contact us to confirm the available specifications.

Operation & Maintenance

User Guide

The shutdown sequence for vacuum filtration is completely different from gravity filtration — get it wrong and water will suck back into your sample.

🚨 The One Rule You Must Remember:
Shutdown sequence: Disconnect the tubing FIRST, THEN turn off the pump!
Turn off the pump first and water will suck back into your flask — ruining your sample.

I. Before You Start

Check all glassware for cracks — filter flasks are heavy-wall but cracks are dangerous under vacuum
Make sure the rubber stopper fits well between the funnel and flask — leaks kill vacuum
Use heavy-wall tubing — standard tubing collapses under vacuum
Empty the safety trap if there's water in it

Assembly sequence

Clamp the filter flask to the iron stand, mouth up
Fit the Buchner funnel into the stopper and insert into the flask — the funnel stem bevel should face the flask side arm
Connect the safety trap in series: flask side arm → safety trap (short tube in, long tube out) → vacuum pump
Use heavy-wall tubing for all connections — secure with clamps

III. Filter Paper & Wetting

Cut the filter paper slightly smaller than the funnel inner diameter, but cover all the holes
Place the paper in the funnel, wet with a small amount of solvent (water or your solvent), and turn on the vacuum briefly to seat the paper against the plate
This step is critical — a loose paper lets sample bypass the filter

IV. Filtration

Turn on the vacuum pump and let the vacuum stabilize
Decant the supernatant first — let most of the liquid pass before adding the precipitate to prevent clogging
Each pour should fill no more than 2/3 of the funnel capacity
Pour the liquid into the center of the funnel — pouring at the edge lets liquid bypass the paper
If cracks appear in the solid layer during filtration, gently press them with a glass stopper

V. Washing the Precipitate

After the solution is drawn through, add a small amount of washing solution to rinse the precipitate
Add the wash solution with the vacuum running — it pulls the wash through for cleaner results
Repeat 2–3 times until the filtrate runs clear

VI. Shutdown (The Critical Step)

Disconnect the tubing between the filter flask and the vacuum pump FIRST (or open the safety trap vent) to release the vacuum
Then turn off the vacuum pump
Reverse the order and water will suck back into your flask — ruining your sample and potentially damaging the pump

VII. Collecting the Solid & Cleanup

Remove the Buchner funnel from the flask
Hold the funnel stem in your left hand, invert it, and tap gently with your right hand — the solid and paper will fall out
Peel off the paper and dry the solid for weighing
Clean the flask, funnel, and safety trap thoroughly — residues are harder to remove once dry

📌 Safety Trap Connection — Many People Get This Wrong:

The safety trap has two ports: short tube connects to the filter flask, long tube connects to the vacuum pump. Reverse the connection and the suck-back protection is gone.
The safety trap catches back-flowing water before it reaches your sample.

💡 From a Seasoned Lab Hand:

"Disconnect first, pump off second" — write these six words on your bench, read them before every filtration. Newbies mess this up constantly, and even experienced hands slip sometimes. The safety trap helps, but don't rely on it completely.
Filtration speed depends on both vacuum level and paper pore size. Higher vacuum isn't always better — too much vacuum tears the paper and lets fine particles through.
If filtration is unusually slow, check: ① Is the paper clogged? ② Is there a leak in the vacuum line? ③ Is the safety trap stopper loose?
Pour the filtrate out of the filter flask through the mouth, not the side arm — the side arm is for vacuum, not for draining.

Care & Notes

Show care & notes

⚠️ Safety & Compliance Checklist

Shutdown sequence is non-negotiable

Disconnect (or vent) first, then turn off the pump — this is critical

Strong acids/bases

Use a sintered glass funnel or glass fiber paper — standard paper won't hold up

Gelatinous precipitates and ultra-fine particles

Not suitable for vacuum filtration — they'll clog the paper

Tubing

Must be heavy-wall — standard tubing collapses under vacuum

Do not

Filter flasks are heavy-wall but not indestructible: Never use cracked glassware under vacuum — it can implode

Vacuum Filtration Apparatus

Specifications

Component List

Product Description

I. How It Works

II. What's in the Setup

III. Choosing the Right Funnel

IV. Material & Workmanship

Applications

Crystal Collection

Catalyst Recovery

Hot Filtration in Recrystallization

Environmental Monitoring

Microbiology Sample Prep

Pharmaceutical Decolorization

User Guide

I. Before You Start

Assembly sequence

III. Filter Paper & Wetting

IV. Filtration

V. Washing the Precipitate

VI. Shutdown (The Critical Step)

VII. Collecting the Solid & Cleanup

Care & Notes

Shutdown sequence is non-negotiable

Strong acids/bases

Gelatinous precipitates and ultra-fine particles

Tubing

Need This Apparatus Kit?

Vacuum Filtration Apparatus

Specifications

Component List

Product Description

I. How It Works

II. What's in the Setup

III. Choosing the Right Funnel

IV. Material & Workmanship

Applications

Crystal Collection

Catalyst Recovery

Hot Filtration in Recrystallization

Environmental Monitoring

Microbiology Sample Prep

Pharmaceutical Decolorization

User Guide

I. Before You Start

Assembly sequence

III. Filter Paper & Wetting

IV. Filtration

V. Washing the Precipitate

VI. Shutdown (The Critical Step)

VII. Collecting the Solid & Cleanup

Care & Notes

Shutdown sequence is non-negotiable

Strong acids/bases

Gelatinous precipitates and ultra-fine particles

Tubing

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