Views: 0 Author: Site Editor Publish Time: 2026-09-07 Origin: Site
An IQF line for frozen fruit puree needs an evaporator that can deliver the required low-temperature air, airflow pattern and hygienic operating conditions for discrete puree pieces. A blast freezer evaporator for IQF frozen fruit puree processing is not selected from freezer-room volume alone. We match the evaporator to the puree format, feed rate, product thickness, freezing method, air velocity, belt or tray layout, refrigeration circuit and defrost sequence.
At CSTHEATEXCHANGER, we design and supply blast-freezer unit coolers, ammonia evaporators and stainless-steel evaporator options for industrial food-freezing applications. Our published IQF Stainless Steel Evaporator information describes equipment for industrial cold rooms, frozen storage, blast freezing and fast-cooling rooms. Our blast-freezer information also identifies fruits and vegetables among the food products that can be rapidly frozen with an evaporator and forced-air system.
In this article, we use “frozen fruit puree” to mean puree that has been deposited, portioned, dropped, sheeted or otherwise formed into separate pieces before IQF freezing. A tank of bulk puree does not become an IQF product simply because the room is cold; it needs a different heat-transfer and product-handling method. We explain how we evaluate the evaporator, airflow, materials, defrost and installation for the discrete-piece application.
Fruit puree contains water, dissolved solids, acids, fibers and, depending on the recipe, added sugar or other ingredients. The product can be sticky, soft and sensitive to surface drying. Its freezing behavior depends on formulation, portion geometry, deposit temperature, belt loading and the required final product condition.
We therefore begin with the product format. A thin puree sheet, small drop, cube, pellet or filled portion will exchange heat differently from a thick block. The belt speed and residence time also depend on the product thickness and the customer’s process. If the puree is supplied as a bulk liquid, plate freezing, scraped-surface freezing, block freezing or another process may be more appropriate than IQF air freezing.
CSTHEATEXCHANGER’s public IQF evaporator information covers fast freezing and blast-freezing applications, while the published IQF product page describes a stainless-steel evaporator for industrial cold rooms and fast-cooling rooms. These product applications provide a starting point for design discussions. They do not establish one universal freezer configuration for every puree recipe.
Our goal is to remove heat consistently from the product surface and core while maintaining an airflow pattern that supports separation. We consider the evaporator, fan, belt, product feed, air return and defrost system together. We do not promise a particular freezing time, texture or outlet temperature without the product data and a project-specific calculation.
Before we size an evaporator, we ask the customer to describe the production line. We need more than the cold-room dimensions because the major refrigeration load usually comes from the product, incoming air and process equipment.
Our design review normally includes:
Fruit type, puree recipe and soluble-solids content.
Puree temperature at the freezer inlet.
Piece shape, thickness, weight and target separation.
Product feed rate in kilograms per hour.
Belt, tray, fluidized-bed or spiral conveying arrangement.
Required outlet or core condition defined by the process team.
Freezer chamber dimensions and internal air paths.
Refrigerant or secondary-fluid system available at the site.
Evaporating condition, pressure, expansion and control method.
Fan airflow, static pressure and acceptable product air velocity.
Defrost method, frequency, drainage and available recovery time.
Washdown, sanitation, corrosion and food-hygiene requirements.
Available power, service access, drawings and installation constraints.
We then review the heat load. The responsible refrigeration designer should account for the sensible cooling of the puree, phase-change heat when the water fraction freezes, product throughput, belt and equipment heat, fan motors, wall heat gain, door opening, infiltration and defrost recovery. A nominal product rate without inlet condition or product geometry is not sufficient for a reliable evaporator selection.
CSTHEATEXCHANGER states that its engineers use design software and can provide design data and production drawings. We use the customer’s process information to create the coil circuiting, header arrangement, fan selection, casing and connection details instead of treating a catalogue model as automatically suitable.
The evaporator removes heat from the air circulating through the freezer. Depending on the selected refrigeration system, refrigerant or secondary fluid flows through the coil while fans move cold air across the heat-transfer surface. The air then passes over the puree pieces, absorbs product heat and returns to the evaporator for another cooling cycle.
For ammonia systems, the liquid ammonia enters the evaporator after pressure reduction, absorbs heat as it evaporates and returns as vapor toward the compressor. CSTHEATEXCHANGER’s published ammonia blast-freezer information describes this phase-change process and identifies the evaporator, expansion device and fan system as key parts of the freezing arrangement.
For other projects, the unit may be designed for CO₂, glycol or another refrigerant or secondary fluid. CSTHEATEXCHANGER’s blast-freezer product information lists R410A, CO₂, ammonia, glycol and other special refrigerants as available options for suitable configurations. The final choice depends on the customer’s refrigeration plant, safety requirements, pressure conditions, temperature range and local engineering practice.
We also review whether the line uses a straight tunnel, spiral freezer, fluidized-bed system or batch chamber. The coil and fan arrangement must fit the equipment geometry. A spiral freezer may require a different air path from a single-pass tunnel, while a small puree portion line may need a compact stainless-steel coil with controlled airflow rather than a large cold-room unit.
Airflow affects freezing rate, product separation, moisture loss and temperature uniformity. We aim to move cold air across the puree pieces consistently without creating areas where pieces remain warm or stick together. The air path must also work with the belt opening, tray spacing, product distribution and return-air route.
CSTHEATEXCHANGER’s blast-freezer information describes high-velocity fans that circulate cold air around products. Its IQF evaporator information states that triphase fans can support both fast cooling and low-air-circulation applications. We treat these features as design options and match fan performance to the actual product and freezer resistance.
We review several airflow questions:
Does air pass evenly through the full belt width?
Are there dead zones at the product inlet, outlet or chamber corners?
Will the airflow disturb small or lightweight puree pieces?
Does the air velocity support separation without excessive surface drying?
Can the return air reach the coil without bypassing the heat-transfer area?
Does the fan create enough static pressure for filters, guards and internal components?
The answer depends on the line. The air velocity that works for one puree piece may be unsuitable for another. Product viscosity, surface condition, deposit geometry and belt loading all affect the result. We therefore recommend testing the air distribution with a representative product load or a validated commissioning procedure.
An evaporator with sufficient coil area cannot compensate for poor product distribution or blocked air passages. Operators should maintain the planned belt loading and keep access panels, return paths and fan guards clean.
Frozen fruit puree processing involves moisture, sugars, organic acids and regular cleaning. The evaporator, drain pan, casing, fasteners and supports must be considered as a food-processing assembly. Stainless steel may be selected for relevant components, but the actual grade and scope must be stated in the quotation.
CSTHEATEXCHANGER’s IQF page identifies a stainless-steel evaporator and describes it for industrial freezing and fast-cooling applications. Its blast-freezer product information lists stainless steel, copper, aluminum, Cu-Ni, brass and titanium as material options for suitable designs. We select the tube, fin, casing and drain-pan materials according to refrigerant compatibility, pressure, temperature, cleaning chemicals, corrosion exposure and the customer’s hygiene specification.
A stainless-steel name does not automatically prove hygienic design or make every surface suitable for every cleaning chemical. We review welds, corners, drainability, access, surface finish, seals, fasteners and the risk of standing water. We also confirm whether the selected coil coating or fin material can withstand the intended washdown and sanitation procedure.
CSTHEATEXCHANGER reports using automatic welding equipment for its IQF stainless-steel evaporator production and describes lower leakage rates and improved appearance as manufacturing benefits. The customer should request the actual material certificate, inspection records, pressure or leak-test documentation and surface specification included in the project scope.
The evaporator should be designed for cleaning access. The food plant remains responsible for its sanitation program, allergen controls, environmental monitoring and release procedure.
Fruit puree brings moisture into the freezer, and humid infiltration can add more. At low operating temperatures, frost can accumulate on the evaporator coil. As frost thickens, it restricts airflow and reduces heat transfer. A suitable defrost plan is therefore part of the IQF evaporator design.
We review the product moisture load, freezer humidity, operating cycle, frost rate, defrost trigger, drainage route and production schedule. The appropriate method may include hot-gas defrost, electric defrost or another arrangement approved for the refrigeration system. CSTHEATEXCHANGER’s ammonia blast-freezer information describes hot-ammonia or hot-gas defrost and notes that the method requires a more complex operating procedure.
The defrost sequence must protect the product and the equipment. We confirm how the freezer is isolated, how fans are controlled, how meltwater drains and how the system returns to freezing operation. The drain pan should be sloped toward the outlet, and the drain line should be protected against blockage and refreezing.
For a food-processing plant, drainage is a hygiene issue as well as a refrigeration issue. Meltwater should not collect above product zones or flow across areas that are difficult to clean. The operator should be able to inspect the coil face, drain pan and drain line during scheduled sanitation.
The actual defrost interval cannot be copied from another fruit puree line. We set it according to the product, air conditions and observed frost pattern, subject to the responsible refrigeration engineer’s approval.
We plan installation around the freezer manufacturer’s chamber and conveyor layout. Before production, we verify the evaporator dimensions, mounting points, coil orientation, header connections, fan access, drain route and service clearances. We also check how the unit will be lifted into the freezer and how the plant will protect food-contact areas during installation.
For an ammonia system, qualified refrigeration contractors must complete piping, pressure testing, safety checks, charging and commissioning according to the approved design and applicable local requirements. The same principle applies to CO₂ or glycol systems: the installation team must follow the selected system’s safety and commissioning procedures.
Our pre-start checklist includes:
We inspect the coil, headers, casing, supports and protective guards.
We verify the refrigerant or fluid connections against the approved drawings.
We check fan rotation, vibration, motor wiring and control response.
We inspect the drain pan, drain line and defrost connections.
We confirm sensors, valves, alarms and expansion control signals.
We check the freezer air path with the belt, trays or racks installed.
We record baseline air and product readings under a representative load.
CSTHEATEXCHANGER states that it can provide production drawings and design data for customized projects. We use the approved equipment schedule and freezer interface drawings during commissioning. The final product condition, freezing time and food-safety acceptance criteria must come from the customer’s process validation and quality documentation.
Maintenance protects freezing performance, hygiene and production continuity. Fruit sugars and puree residues can create difficult cleaning conditions if they enter areas that are not designed for washdown. Frost, dust, packaging fibers and water can also affect the coil, fan, drain pan and electrical components.
Our maintenance review includes:
Inspecting the coil face for frost, residue, corrosion or damage.
Cleaning the fins and casing with an approved food-plant procedure.
Checking fans, blades, motors, bearings, guards and vibration.
Confirming the defrost cycle and condensate drainage.
Inspecting drain pans, traps, insulation and pipe supports.
Checking expansion devices, sensors, alarms and operating pressures.
Reviewing air filters or guards where fitted.
Recording operating hours, faults, defrost events and corrective work.
The cleaning method must suit the coil material, coating, seals, electrical parts and refrigeration circuit. High-pressure water can bend fins or enter motors and controls if applied incorrectly. The plant should isolate equipment safely, follow lockout procedures and use trained personnel for refrigeration service.
CSTHEATEXCHANGER describes leak testing and design support in its public company information. Customers should retain the actual test reports, material documents, drawings, warranty terms and maintenance instructions supplied for their evaporator.
The maintenance interval should reflect production hours, puree formulation, humidity, washdown frequency and frost formation. A seasonal fruit line may require a different schedule from a continuous industrial line.
When we prepare an IQF evaporator proposal, we connect the equipment to the puree process. We define the product form, feed rate, inlet condition, required outlet condition, belt or spiral layout, air velocity, refrigeration system, materials, defrost, drainage, hygiene and installation constraints.
CSTHEATEXCHANGER’s Blast Freezer Unit Cooler information describes customized blast-freezer coolers, multiple refrigerant options, fan and coil construction, material choices and defrost-related design considerations. Its IQF Stainless Steel Evaporator page identifies industrial freezing, fast cooling and frozen-storage applications, with published capacity information that must still be matched to the actual project duty. The Ammonia Blast Freezer Evaporator information explains ammonia evaporation, forced air and hot-ammonia defrost.
We ask the customer to provide the puree recipe, piece size, feed rate, inlet condition, target product condition, freezer drawings, belt speed, airflow layout, refrigerant conditions, sanitation procedure, electrical supply and required documentation. Contact CSTHEATEXCHANGER to discuss a blast freezer evaporator for your IQF frozen fruit puree processing line.
A properly matched evaporator can support stable freezing and product handling, but final results depend on the complete IQF line, product formulation, feed system, airflow, refrigeration plant, sanitation program and process validation. We recommend defining the design conditions and acceptance criteria in the project quotation and commissioning plan.
