What Is a PSD Bag Lifting Centrifuge?

The PSD is a flat plate batch filter centrifuge that discharges its cake by hoisting the filter bag out of the basket, and which adds two features for demanding duty: a CIP spray system that cleans the interior without opening the machine, and nitrogen blanketing that keeps air away from solvent-wet solids. The bag carries the cake out as one piece, so nothing is scraped off the basket wall and no crystals are broken. Because the interior can be cleaned in place and the process zone can be inerted, a bag lifting centrifuge in this execution serves products that are simultaneously delicate, toxic and flammable — a combination that defeats most other machine types.

Working Principle

1) Load the bag and close. The filter bag is fitted with the cover open, then the machine is closed and sealed. 2) Inert and feed. Nitrogen is admitted and oxygen is verified; slurry is then fed at a controlled rate. 3) Filtration and washing. Liquid drains through the bag while solids build as a cake, and wash liquid is applied to displace mother liquor. 4) Spin-dry. The basket runs at full speed to reach the moisture target. 5) Bag discharge. The cover opens, the hoist lifts the bag, and the cake leaves as a single block with no manual contact. 6) CIP clean. The spray system cleans the basket, casing and seals in place, so the next batch starts from a defined clean state without an operator entering the machine.

Key Features

Whole cake, no scraping — the bag is lifted out, so fragile and needle-shaped crystals are not damaged and the basket wall is never cut.

CIP cleaning in place — spray nozzles clean the interior to a defined standard without opening the machine or sending anyone inside.

Nitrogen protection — blanketing and oxygen verification allow solvent-wet and oxidation-sensitive products to be handled safely.

Low operator exposure — discharge happens by hoist and cleaning happens by CIP, so the operator's contact with a toxic product is minimal.

Fast changeover — the bag is a removable liner, so switching products means fitting a new bag rather than validating a hand-cleaned basket.

GMP-ready surfaces — 304 or 316L with polished, crevice-free internals and documentation support for validation.

Typical Applications

The PSD bag lifting centrifuge is chosen where the product is too delicate for a scraper, too toxic for manual handling and too flammable for an open machine:

• toxic pharmaceutical intermediates　· solvent-wet active ingredients　· flammable dye intermediates　· pesticide technical　· oxidation-sensitive chemicals　· fragile crystalline products　· fine chemicals with solvent wash　· agricultural chemical intermediates

Selection Guide

Compare the discharge methods, because the choice decides both your product quality and your operator's exposure:

Specify the PSD when you need all three: intact crystals, in-place cleaning and inert atmosphere. If your product is simply fragile but not hazardous, a plain bag lifting machine does the same job for less; if it is hazardous but free-flowing, a vacuum discharge machine may be enough.

Technical Specifications

Customization & Options

CIP spray ring with drain and documented coverage; nitrogen blanketing with oxygen analyser and interlock; static-dissipating bag material; Halar, PFA or rubber lining; 316L or higher alloy contact parts; explosion-proof motor and panel; hoist and bag handling gear; closed cake discharge to a sealed receiver; documentation package for validation and safety review.

FAQ

Spray nozzles distributed around the casing wash the basket, the underside of the cover and the process seals with cleaning liquid, which then drains through a dedicated outlet. The coverage pattern is defined during design, so the clean state is repeatable rather than dependent on how carefully somebody scrubbed. This is what makes product changeover documentable.

Not always, but it becomes essential when the solvent can form an explosive atmosphere inside the basket or when the product oxidizes in air. The controller verifies oxygen content before feed is allowed, so a batch cannot start in an unsafe condition.

Because the clean cycle is fixed and repeatable, and because documentation of the coverage pattern and cleaning parameters can be supplied. For pharmaceutical users who need formal validation, we provide the surface finish records and material certificates that a cleaning validation protocol requires.

The bag is a consumable and is normally replaced on a schedule rather than run to failure, which removes most of the risk. Bag condition is inspected whenever the cover is open, so damage is found before it becomes a contamination event.

Yes, and that combination is precisely what the PSD is built for. Nitrogen blanketing plus a sealed process zone handles the flammability, the hoist keeps the operator clear of the toxicity, and CIP handles the cleaning without sending anyone inside.

Why Jiangsu Shengli Centrifuge

Jiangsu Shengli Centrifuge Manufacturing Co., Ltd. builds this equipment in a 158,905 m2 plant with in-house machining, hard-facing and rotor dynamic balancing. The company holds ISO 9001, ISO 14001 and ISO 45001 certification, CE marking and more than 30 patents, and has supplied machines to customers in over 30 countries. Every unit is balanced and run-tested before shipment, and the balancing report is supplied with the machine.

Request a Quote or a Free Separation Test

Send us a sample of your material and we will run it on a pilot machine, then report the measured moisture, throughput and clarity before you order. Tell us your material and your target, and our engineers will recommend the model, the material of construction and the options that fit.