Fluidized Bed Freezer

Square’s Fluidized Tunnel Freezer is the perfect solution for quickly and efficiently freezing small food items such as diced fruits, vegetables, meat, poultry, seafood, and dairy products. Our freezer features a highly efficient and sanitary evaporator that utilizes the latest liquid supply method, resulting in a 20% higher heat exchange compared to traditional methods.

We offer two types of fluidized tunnel freezers: semi-fluidized and full-fluidized, catering to diverse product freezing applications. As the co-drafter of the China National Standard for fluidized bed freezers, Square Technology Group Co., Ltd. takes pride in providing a range of models to suit various food products.

Our goal is to deliver efficient, hygienic, and cost-effective IQF solutions to our clients.

Upward airflow lifts and tumbles product for even freezing.
IQF technology ensures products freeze individually, maintaining shape and quality.
Advanced design minimizes water loss, preserving natural moisture and quality.

Product Features

Why Choose Square's Fluidized Bed Freezer

Explore the original product feature overview, including Efficient Air Flow, Two Stage Freezing, CIP Auto Cleaning System, and the key technical advantages behind this system.

Efficient Air Flow
CFD(Computational Fluid Dynamic) design ensures optimum airflow, minimum air velocity loss, and even air distribution.
Two Stage Freezing
- The first stage: Instantly freeze the product surface to prevent moisture loss and caking.
- The second stage: Product deep freezing.
- The two stages adopt different freezing modes to achieve better results and higher capacity.
CIP Auto Cleaning System
Different cleaning modes are optional. Clean and disinfect the interior of the quick-frozen machine in all aspects to meet the sanitary requirements of food safety production.
Efficient Centrifugal Fan
We choose from a variety of high-efficiency fans to suit different scenarios.
Vibration Device / Mixing Device / Pulse Device
A variety of auxiliary devices for different products to enhance the freezing quality, keep the product separate, and increase freezing capacity.
Efficient Evaporator
Our fluidized tunnel freezer’s evaporator is designed using advanced European heat exchanger software, ensuring optimal performance.

The tubes are hydraulically expanded, resulting in a more uniform expansion and tighter fit between the tube and fins, which enhances heat exchange efficiency.

The variable fin pitch design delays frost formation on the fin surface, leading to longer frosting intervals. The evaporator is easily accessible for convenient cleaning and maintenance.
ADF (Air Defrosting System)
The air defrosting system (ADF) is equipped to direct pulses of pressurized high-velocity air back and forth over the evaporator fins while the freezer is running, preventing frost and snow accumulation.

This extends defrosting intervals and increases freezing capacity.

Technical Specifications

Parameters

Custom dimensions, capacity, and configuration matched to your production requirements.

Configuration	Two-zone fluidized bed — Zone 1 (high velocity) + Zone 2 (moderate velocity)
Capacity	500 – 6,000 kg/hr (product-dependent)
Bed width	800 – 2,000 mm
Bed length	4 – 14 m (Zone 1 + Zone 2)
Air velocity	Zone 1: 4–6 m/s; Zone 2: 2–4 m/s (adjustable)
Operating temperature	−30°C to −40°C (air)
Refrigerant	NH₃ (Ammonia) / CO₂ — pump-recirculated
Evaporator	Industrial finned-tube, twin-bank for continuous defrost, hot gas defrost
Freezing time	6 – 15 min (product-dependent)
Bed plate	Interchangeable perforated plates — hole pattern per product type
Dehydration rate	< 1.5% (cryogenic-comparable, air-based)
Control system	PLC touchscreen, recipe storage, per-zone velocity & temperature, data logging
Typical lead time	16–20 weeks
Design life	15+ years (structural); 8–12 years (mechanical components)

Design Details

How each subsystem is engineered

Expand any section below for the engineering approach behind each critical subsystem — with links to detailed Technology pages.

How Fluidization Works

Fluidization occurs when the upward air velocity equals or exceeds the minimum fluidization velocity — the point at which aerodynamic drag force on each particle equals its weight:

Particles become suspended in the air stream
Each particle is surrounded by cold air on all surfaces
The bed behaves like a fluid — particles flow and mix gently
Heat transfer is maximized because every surface is in direct contact with cold air

Minimum fluidization velocity depends on particle size, density, and shape. Peas fluidize at ~2–3 m/s. Green beans require ~3–4 m/s. The bed plate, velocity, and bed depth are engineered per product.

Two-Zone Freezing Process

Zone 1 — Surface Crust: High velocity (4–6 m/s) creates vigorous fluidization. Product surface rapidly drops below freezing, forming a thin frozen crust that locks in moisture and prevents sticking. Retention: 2–4 minutes.

Zone 2 — Core Freeze: Lower velocity (2–4 m/s) maintains gentle fluidization while product core freezes completely. Lower velocity reduces fan energy and prevents product damage. Retention: 4–10 minutes.

Dehydration: Why Fluidized Bed Minimizes Weight Loss

Dehydration is a significant economic factor — 1% weight loss on 10,000 ton/year = 100 tons of lost salable product:

Short residence time: 6–15 minutes vs 15–60 min in spiral, hours in carton/blast
Rapid surface crust: surface water immobilized as ice within 1–3 minutes
Cold air (−30 to −40°C): low vapor pressure driving force vs warmer air
High air humidity in freezer: air near-saturation at low temperature

Product Suitability & Limitations

Ideal for: Individual, separable pieces — peas, corn, diced vegetables, berries, shrimp, scallops, diced meat. Particle size 5–50 mm (3–50 g per piece). Relatively uniform size distribution.

Not suitable for: Large pieces (> 80 mm) — cannot be fluidized. Very light products — would be blown out of bed. Products that clump when wet. Flat/sheet products — use tunnel or spiral.

Bed Plate Design & Changeover

The bed plate is product-specific:

Hole diameter: 2–8 mm, selected per product particle size
Open area ratio: 15–30%, determines air velocity at given fan speed
Quick-change design: bed plates slide out on rails, swap < 15 minutes
Multiple bed plates kept on-site for different products
Bed plate angle: adjustable 0–5° from horizontal to control transport speed

Proven in These Food Applications

IQF Vegetables

IQF Fruits

IQF Shrimp & Seafood

Cooked Grains & Pasta

Frequently Asked Questions

Is It Difficult To Maintain Hygiene In A System With So Many Air And Mechanical Components?

Not at all. Square’s freezer features CIP automatic cleaning, fully-welded food-grade stainless steel structures, and open-access designs to meet the strictest food safety standards.

What Is the Difference Between Semi-Fluidized And Full-Fluidized Tunnel Freezers?

Semi-fluidized models lift product only slightly for partial tumbling, ideal for heavier items. Full-fluidized designs fully suspend and tumble lighter products for maximum freezing uniformity.

What Certifications Do You Hold?

We own CE, EAC, INF, CNAS, ISO, ASME, PED, U2, CSA, CRN certifications and 300+ patents, as well as 350+ engineers. Square vertically integrated production ensures quality control from raw materials.

What Customization Services Do You Offer?

Square offers customized one-stop cold chain solution that meets your requirements. Our Fluidized Bed Freezers can be fully customized to suit different food products, freezing capacities, belt widths, airflow settings, and even include optional add-ons like CIP cleaning systems or pre-treatment lines—ensuring optimal performance for your specific processing needs.

What Is A Fluidized Bed Freezer And How Does It Work?

A fluidized bed freezer uses high-velocity upward airflow to lift and tumble small food items, allowing each piece to freeze individually and uniformly—ideal for IQF (Individual Quick Freezing) applications.

Case Studies