Laboratory swing granulator

The laboratory swing granulator is a basic laboratory equipment that quickly and economically converts wet powder into uniform particles through mechanical extrusion. Its core value lies in improving the physical properties of materials (especially fluidity), preparing qualified intermediates for subsequent processes such as compression and packaging, and serving as a tool for product development and small-scale testing.

The main purpose of the laboratory swing granulator is not drying, but "granulation", which is to process fine powder into particles with a certain shape and size. This is a preprocessing process.

Its structure is relatively simple, mainly composed of the following parts:

Hopper: used to store wet powder materials to be granulated.

Rotating drum ("grinding knife"): a hexagonal or shuttle shaped drum with a scraper. This is the core working component.

Mesh (mesh ring): A replaceable circular stainless steel mesh with a pore size that determines the final particle diameter.

Transmission mechanism: an eccentric shaft driven by a motor, which drives the rotating drum to perform reciprocating "swinging" motion.

Working Principle:

Put the wet powder pre mixed with adhesive (such as water, ethanol, starch slurry, etc.) into the hopper.

Start the machine, and the rotating drum, driven by the transmission mechanism, performs continuous and reciprocating squeezing action against the screen mesh.

The damp powder is forced to pass through the small holes on the sieve under the pressure of the drum, and is cut into cylindrical wet particles of uniform size.

The particles are discharged from below the sieve and collected for subsequent drying treatment.

Main purpose:

Improve powder flowability

Core function: The flowability of fine powder is poor, which can lead to inaccurate dosage and uneven filling during subsequent tablet pressing, capsule filling, or packaging processes. After being made into particles, the flowability is greatly improved, ensuring smooth production and product quality.

Provide intermediates for tablet pressing

In the pharmaceutical industry, the vast majority of tablets are not directly pressed from powder, but are first made into granules (known as "intermediates") and then compressed into tablets. Swing granulation is one of the methods for preparing this type of tablet pellet.

Control the bulk density and volume

Making fluffy powder into dense particles can reduce the total volume and facilitate packaging, storage, and transportation.

Improve product appearance

The particles produced look more regular and aesthetically pleasing than powders.

Prevent component segregation

When a mixture contains multiple components with different densities or particle sizes, separation is prone to occur during transportation and processing, resulting in uneven composition. After being made into particles, all components are "locked" inside the particles, ensuring the uniformity of mixing.

Adjust dissolution rate

Dense particles dissolve slower than powders and can sometimes be used to regulate the release behavior of products.

Advantage:

Simple structure, easy operation: low equipment cost, convenient maintenance, low learning threshold.

Rapid granulation: suitable for laboratory and small batch production that require rapid preparation of samples.

Particle uniformity: Under appropriate material conditions, cylindrical particles with narrow particle size distribution can be produced.

Easy to clean: The parts in contact with materials, such as sieves and hoppers, are easy to disassemble and clean, meeting the laboratory's requirements for hygiene and preventing cross contamination.

High flexibility: By replacing the sieve with different aperture sizes, it is easy to produce particles of different diameters.

Application:

Pharmaceutical laboratory: preparing pellet samples for tablet development of new drugs; Production of drugs for small-scale clinical trials.

Food R&D laboratory: produces solid beverage granules, seasoning granules, etc.

Chemical laboratory: preparation of catalyst carriers, dye particles, etc.

Laboratory swing granulatorTechnical specifications:

Composition of laboratory swing granulator

The core components of the laboratory swing granulator include:

Granulation room

Cylindrical stainless steel chamber (capacity 0.5-5L), equipped with a detachable screen (aperture 0.3-2.0mm) and a swinging extrusion knife.

Transmission system

The motor (power 0.2-0.75kW) drives the crank connecting rod mechanism, which drives the horizontal reciprocating motion of the extrusion knife (frequency 20-60 times/minute).

Regulating device

Pressure adjustment knob: controls the gap between the squeezing knife and the sieve (0.1-0.5mm).

Screen fixing bracket: quick detachable design, suitable for different aperture screens.

Cleaning components

Splash proof baffle and material tray (made of stainless steel or PP material), supporting manual or ultrasonic cleaning.

control system

Simple speed control panel (variable frequency or continuously variable transmission), some models are equipped with a timer (adjustable from 0-30 minutes).

Operating process of laboratory swing granulator

1. Preparation before startup

Cleaning and disinfection:

Wipe the granulation room, extrusion knife, and sieve with 75% ethanol, and dry with a laboratory dust-free cloth (pharmaceutical products must comply with GMP standards).

Check the sealing gasket for damage and lubricate the guide rail with food grade white oil or silicone grease.

Screen installation:

Select a sieve (such as Φ 0.8mm) based on the target particle size, ensuring it is parallel to the extrusion knife and has a uniform gap (recommended 0.2-0.3mm).

Parameter setting:

Set the oscillation frequency (e.g. 30-40 times/minute) and granulation time (3-10 minutes/batch).

2. Granulation operation

Wet material preparation:

Pre mix the powder with a binder (such as HPMC aqueous solution, ethanol) until it forms a "ball by hand and disperses upon light pressure" state (with a moisture content of 10-25%).

Feeding granulation:

Spread the wet material evenly on the sieve (thickness ≤ 20mm) and install the splash guard.

Start the equipment, observe whether the reciprocating motion of the squeezing knife is smooth, and adjust the pressure knob to an appropriate level (based on the particle forming and non clogging of the sieve).

Monitor the particle forming status through the window:

Loose particles: Increase the oscillation frequency or add adhesive.

Particle adhesion: Reduce frequency or decrease the amount of adhesive used.

Discharge collection:

After granulation is completed, stop the machine, take out the sieve and gently tap or use a soft brush to assist in discharging to avoid particle breakage.

3. Shutdown and Cleaning

Clean immediately:

Disassemble the sieve and squeezing knife, clean them with ultrasonic cleaning (purified water or 1% NaOH solution), and dry them for later use.

Use a vacuum cleaner to remove residual powder in the granulation room, and wipe with ethanol for disinfection (pharmaceutical laboratories need to record cleaning logs).

Check reset:

Turn off the power, check the wear of the guide rail (if the scratch depth is greater than 0.1mm, it needs to be polished), and reset the pressure adjustment knob to zero position.

Maintenance and upkeep of laboratory swing granulator

1. Daily maintenance

Cleaning:

Clean after each batch to prevent material clumping (especially sugar or hygroscopic materials).

Check if the screen mesh is deformed (if the flatness is greater than 0.5mm, it needs to be replaced).

Lubrication:

Add a small amount of lubricating grease (such as PTFE based grease) to the crankshaft connecting rod bearings every week to avoid contaminating the samples.

Apply a thin layer of silicone grease (water-resistant and corrosion-resistant) to the guide rail every month.

calibration

Verify the oscillation frequency monthly (measured with a photoelectric counter, if it exceeds 5%, the transmission mechanism needs to be inspected).

2. Regular maintenance

Quarterly maintenance:

Check the carbon brush of the motor (for brushed motor models, if the remaining length is less than 1/3, it needs to be replaced).

Test the parallelism between the extrusion knife and the sieve (use a feeler gauge to check, adjust if the deviation is greater than 0.1mm).

Annual maintenance:

Replace the sealing gasket (mandatory replacement when aging hardness>70 Shore A).

Check the circuit wiring and tighten loose terminals (to prevent poor contact).

3. Common fault handling

Screen blockage:

Reason: The material is too wet or the mesh size is too small.

Treatment: Pre dry the material to a moisture content of ≤ 15%, and replace the large aperture sieve (such as Φ 1.2mm).

Uneven particle size:

Reason: Uneven pressure of the extrusion knife or uneven mixing of wet materials.

Solution: Re mix the wet material and adjust the consistency of the gap between the sieve and the extrusion knife.

Equipment abnormal noise:

Reason: Wear of connecting rod bearings or lack of oil in guide rails.

Solution: Stop the machine and add lubricating grease, replace the bearings (when the radial clearance is greater than 0.15mm).

4、 Safety and Precautions

Mechanical injury prevention:

It is strictly prohibited to reach into the granulation room during operation, and the equipment must be stopped before disassembling the screen.

Equipped with an emergency stop button, it can immediately stop in case of emergencies.

Preventing cross contamination:

When changing the type of material, perform a "clearance confirmation" (the pharmaceutical industry requires residue testing, such as TOC ≤ 500ppb).

Anti static measures:

When handling flammable dust, the equipment should be grounded (resistance ≤ 4 Ω), and an anti-static pad should be laid on the control panel.

Optimization techniques for laboratory swing granulator experiments

Handling of viscous materials:

Spray PTFE coating on the surface of the sieve (to reduce adhesion), or add a small amount of magnesium stearate (0.5-1%) as a lubricant.

Micro granulation:

Use customized small aperture sieve (Φ 0.3mm) and micro feeding tray (suitable for 50-100g samples).

Data recording:

Establish process parameter files (adhesive concentration, swing frequency, particle yield) and optimize reproducibility (RSD ≤ 5%).

The standardized operation and meticulous maintenance of laboratory swing granulators can significantly improve the success rate of granulation (particle qualification rate ≥ 90%) and equipment service life (5-8 years), especially suitable for the research and development needs of multiple varieties and small batches (such as generic drug consistency evaluation). Suggest dynamically adjusting process parameters based on material characteristics such as angle of repose and moisture absorption.