How to Improve Peanut Cleaning Efficiency with Spray Washer

Abstract: The drum high-pressure spray washer with built-in soft brushes is the core equipment for industrial cleaning of agricultural products such as peanuts and nuts. Its unique synergistic mechanism of “brush friction + high-pressure spray” effectively solves the problem of removing stubborn stains on the surface of shelled materials. This article systematically describes the design structure, core component functions, and working principle of this type of washer, deeply analyzes key technical points such as brush material selection, spray system design, transmission mechanism layout, and discusses equipment selection basis and quality control methods combined with actual production needs, providing technical reference for equipment selection and process optimization of nut processing enterprises.

Keywords: drum washer; high-pressure spray; soft brush; peanut cleaning; nut processing

I. Introduction

After peanuts are harvested from the soil, their shells inevitably become coated with fine dust, dirt, bacteria, mold, and other contaminants. These pollutants not only affect product appearance but may also pose food safety risks. Traditional soaking cleaning methods are inefficient and difficult to completely remove stubborn stains. The drum high-pressure spray washer with built-in soft brushes has emerged as required and has become the mainstream cleaning equipment in the nut-processing industry.

This equipment uses a cleaning method that combines brush friction and high-pressure spray. Materials tumble and rub under the action of rotating brushes, combined with high-pressure spray, to wash surface impurities, achieving efficient, uniform cleaning without compromising shell integrity. This article will provide a detailed analysis of the structure and operating principle of this key piece of equipment.

II. Equipment overview and applicable scope

2.1 Equipment definition

A high-pressure spray washer with built-in soft brushes, also called a brush roller washer or brush drum washer, is a specialized piece of equipment that uses the friction of rotating brush rollers and the impact of high-pressure water to clean material surfaces. Its core features are:

• Drum structure: Materials tumble continuously inside the drum for all-around cleaning.
• High-pressure spray: Equipped with special high-pressure fan-shaped nozzles to wash surface stains.
• Soft brush inside: Soft brushes are set on the inner wall or shaft of the drum to remove stubborn dirt through friction.

2.2 Applicable scope

This type of washer is widely applicable, especially suitable for cleaning the following materials:

Table 1 Applicable materials and cleaning requirements

Material category	Examples	Cleaning focus
In-shell nuts	Peanuts, hazelnuts, chestnuts, walnuts, ginkgo	Mud on the shell surface, dust, and mold spots
Kernel nuts	Peeled peanuts, almond kernels, cashews	Residual skin, dust, oil stains
Fruits & vegetables	Potatoes, sweet potatoes, carrots, ginger	Attached soil, root hair
Others	Seafood (clams, etc.), Chinese herbal medicine	Surface sediment, mucus

Core advantage: Multi-purpose – by changing brush hardness, it can achieve cleaning, polishing, peeling, and other functions.

III. Main components of the equipment

The drum high-pressure spray washer with built-in soft brushes consists of several precisely designed subsystems, each of which directly affects the cleaning effect and equipment life.

3.1 Frame and box

The box is the basic support structure, usually made of SUS304 stainless steel, with the following features:

• Corrosion resistance: Food-grade stainless steel, meets hygiene standards, and is non-corrosive.
• Structural strength: Thickness 2-3mm, withstands vibration and load during operation.
• Waterproof design: Electrical components are waterproof to avoid damage due to a humid environment.
• Safety protection: Equipped with overload protection and leakage protection to ensure operator safety.

The inside of the box is often layered. Some advanced equipment sets cleaning chamber, sedimentation chamber, and filtration chamber separately to effectively prevent mud and impurities from blocking the outlet.

3.2 Brush roller system

The brush roller is the core actuating component that directly contacts the material surface. Its design and material selection are crucial.

3.2.1 Brush roller structure

The brush roller consists of a roller body and a brush layer:

• Roller body: Made of stainless steel or high-strength engineering plastic, with grooves for brush installation.
• Brush layer: Made of imported rolled nylon wire, durable.
• Arrangement: Multiple brush rollers are arranged in parallel to form a material channel.

3.2.2 Brush material selection

The brush’s hardness directly affects the cleaning effect. It can be selected based on material characteristics:

Table 2: Brush types and applicable scenarios

Brush type	Hardness	Applicable materials	Main function
Soft brush	Low	Peanuts (in-shell), soft fruits	Remove light dirt, protect shell
Medium-soft brush	Medium	Nuts with thick shells (chestnuts, walnuts)	Remove stubborn mud, keep integrity
Hard brush	High	Potatoes, carrots, root crops	Peeling, deep cleaning

3.2.3 Brush roller layout

Brush rollers usually use an opposite-rotation design. Driven by the motor, they roll in opposite directions to directly create friction with the product, achieving peeling and cleaning. Tumbling materials pass between brushes, and each side fully contacts the brush.

Some patented designs place auxiliary rollers inside the mesh drum, with top brushes on the circumference of the auxiliary rollers to brush the tops of materials, preventing dead corners from being missed during cleaning.

3.3 Spray system

The spray system is the “water source” of the washer, working synergistically with the brush system to achieve efficient cleaning.

3.3.1 Spray pipeline design

• Spray pipes: Located at the top inside the cleaning box, multiple spray pipes are arranged along the direction of material flow.
• Nozzle configuration: Each pipe has multiple high-pressure fan-shaped nozzles at the bottom to cover the entire cleaning area.
• Spray angle: Nozzle direction is adjustable according to material characteristics.

3.3.2 Water circulation system

Modern washers are usually equipped with a water circulation system for water saving and environmental protection:

• Circulation pump: Pressurizes water and delivers it to spray pipes.
• Filter device: A filter screen or sedimentation chamber removes impurities from water, preventing nozzle clogging.
• Drain design: Large-diameter drain for easy discharge of sewage and sediment.

3.3.3 Water quality requirements

Cleaning water should meet drinking water hygiene standards. For products with high hygiene requirements, ozone sterilization can be used to disinfect the cleaning water.

3.4 Transmission system

The transmission system provides rotational power to brush rollers; its design directly affects operational stability and reliability.

3.4.1 Drive mode

Common drive modes:

• Chain drive: Double-row sprockets connected by chains; the drive motor connects to one sprocket for multi-roller synchronous rotation.
• Gear drive: Cycloidal pinwheel reducer full-chain transmission, high efficiency, low noise.

3.4.2 Motor configuration

• Power selection: According to equipment size and capacity, motor power ranges from 1.5kW to 7.5kW.
• Speed regulation: Some models have a frequency converter to adjust brush speed based on the material.
• Overload protection: Equipped with a thermal relay to prevent motor damage.

3.5 Inlet and outlet devices

Inlet: Located at one end, usually with a hopper for continuous feeding.

Outlet types:

• Screw discharge: Screw conveyor automatically discharges cleaned materials, enabling automatic continuous operation.
• End discharge: Open-end outlet; materials are pushed out by brushes.

3.6 Auxiliary devices

• Removable side panels: Easy to disassemble and install cleaning rollers, clean inside brush layers.
• Observation window: For observing internal cleaning.
• Dust cover: Prevents water splashing and external contamination.

IV. Detailed working principle

The working principle of the drum high-pressure spray washer with built-in soft brushes can be summarized as the synergy of three core processes: material tumbling & friction, high-pressure spray rinsing, and continuous automatic discharge.

4.1 Material tumbling and friction cleaning

When material enters the cleaning chamber, brush rollers rotate, driven by the motor. Brush rollers usually adopt an opposite rotation design (adjacent rollers rotate in opposite directions). This produces:

1. Material tumbling: Material tumbles between opposite-rotating brushes, with each side fully contacting the brush.
2. Friction cleaning: Friction between the brush and the material surface removes dirt and impurities attached to the shell.
3. Material collision: Materials collide with each other during tumbling, providing auxiliary cleaning.

Key technical point: Too much material can easily cause overlap, leaving parts unwashed. Patented technology uses auxiliary rollers and limit structures to prevent overlap, ensuring every material is fully cleaned.

4.2 High-pressure spray rinsing

Simultaneously with brush friction, the spray system works continuously:

1. High-pressure water jet: A circulation pump pressurizes water and sends it to spray pipes, where high-pressure nozzles form fan-shaped water curtains.
2. Surface rinsing: High-pressure water directly impacts the material surface, washing away dirt loosened by brushes.
3. Real-time cleaning: Continuous spray of water carries away detached dirt, preventing recontamination.

Synergistic effect: Brush friction and high-pressure spray work together, forming a dual-cleaning mechanism of “scrubbing + rinsing” that improves cleaning by over 50% compared to a single method.

4.3 Continuous discharge and sewage removal

Cleaned materials are automatically discharged through the outlet device:

1. Axial propulsion: Spiral brushes or a tilted drum design move materials toward the outlet during cleaning.
2. Automatic discharge: At the outlet, materials are automatically discharged by gravity or screw pushing.
3. Continuous operation: Feeding, cleaning, and discharging occur simultaneously, achieving continuous production.

Sewage system: Wastewater and impurities are discharged through the drain. The sedimentation chamber collects settled dirt for easy cleaning.

4.4 Workflow summary

Table 3 Cleaning workflow

Step	Process	Main function
1	Feeding	Materials enter the cleaning chamber via the hopper
2	Brush friction & tumbling	Materials enter cleaning chamber via the hopper
3	High-pressure spray	Nozzles spray high-pressure water to wash away stains
4	Continuous rinsing	Clean water constantly flushes,带走 impurities
5	Discharge	Cleaned materials are pushed out by screw/gravity
6	Water circulation	Rollers rotate, materials tumble, and friction removes dirt

V. Technical advantages and application effects

5.1 Comparison with traditional cleaning methods

Table 4 Comparison with traditional soaking cleaning

Parameter	Traditional soaking cleaning	Brush + high-pressure spray washer
Cleaning method	Static soaking, manual scrubbing	Dynamic tumbling + brush friction + spray
Cleaning effect	Difficult to remove stubborn dirt	Thorough removal of mud and stains
Efficiency	Low, batch type, manual	High, continuous, automatic
Water consumption	High, water changed frequently	Low water circulation, 30-50% saving
Damage rate	Manual handling easily causes breakage	Soft brush, low breakage
Labor intensity	High	Low
Hygiene level	Difficult to control cross-contamination	Continuous water change, good hygiene

5.2 Core advantages

1. High cleaning quality: Synergy of brush friction and high-pressure spray thoroughly removes stubborn dirt and contaminants from peanut shells.
2. Low breakage rate: Soft brush material and reasonable brush spacing ensure effective cleaning while maximizing shell integrity.
3. Strong continuous operation capability: Screw or end-discharge design enables simultaneous feeding, cleaning, and discharging, meeting the needs of large-scale industrial production.
4. Water-saving & environmental protection: A circulating water system with sedimentation and filtration enables water reuse, conserving water resources.
5. Multi-purpose: By varying brush hardness, it can perform cleaning, polishing, peeling, and other functions, adapting to different material-processing needs.
6. Easy maintenance: Removable side panels facilitate disassembly, cleaning, and replacement of brush rollers.

5.3 Technical parameters reference

Taking the common GQX series drum washer on the market as an example:

Table 5 GQX series technical parameters

Model	Capacity (kg/h)	Power (kW)	Brush roller length (mm)	Number of rollers	Weight (kg)	Dimensions (L×W×H) mm
GQX-800	300-500	1.5	800	6	180	1200×600×900
GQX-1200	600-1000	2.2	1200	8	260	1700×700×950
GQX-1800	1000-1500	4.0	1800	10	380	2300×800×1050
GQX-2500	1500-2500	5.5	2500	12	550	3000×900×1100

VI. Quality control and maintenance points

6.1 Cleaning effect control

• Brush selection: Choose a brush hardness appropriate to the material. Peanuts and nuts should use soft brushes to avoid shell damage.
• Spray pressure: Too low pressure leads to incomplete cleaning; too high pressure may cause material damage or excessive water consumption. Recommended pressure: 0.2-0.4 MPa.
• Cleaning time: Adjust based on material dirtiness; typically 2-5 minutes. Too short: incomplete cleaning; too long: possible material damage.
• Load capacity: Avoid overloading to prevent material overlap that could affect cleaning. Recommended load: 70-80% of equipment capacity.

6.2 Common faults and troubleshooting

Table 6 Common faults and solutions

Fault	Possible cause	Solution
Incomplete cleaning	Brush worn, pressure low, time short, overload	Replace brush, increase pressure, extend time, reduce load
High damage rate	Brush too hard, too fast speed, material collision	Replace soft brush, reduce speed, check brush alignment
Nozzle clogging	Impurities in water, filter damaged	Clean nozzle, replace filter, clean water tank
Motor overload	Too much material, roller stuck, voltage unstable	Reduce load, check roller for foreign matter, check power
Water leakage	Seal aging, box damage	Replace seal, repair box

6.3 Daily maintenance points

• Brush cleaning: Impurities easily adhere to the brush bristles; it should be disassembled and cleaned regularly. Recommended every 100 running hours.
• Nozzle inspection: Regularly check the nozzle for clogging to maintain the spray effect.
• Lubrication: Bearings and transmission chain need regular grease; recommended monthly.
• Drain cleaning: Regularly clean the sedimentation chamber and filter screen to prevent clogging.
• Motor protection: Start the machine and run before feeding to extend motor life and reduce the chance of motor damage.

VII. Conclusion

The high-pressure drum spray washer with built-in soft brushes is an important piece of equipment for processing agricultural products such as peanuts and nuts. Its unique synergistic cleaning mechanism of “brush friction + high-pressure spray” effectively addresses the inefficiency and poor results of traditional cleaning methods. With an in-depth understanding of equipment structure and operating principles, enterprises can select appropriate equipment models and process parameters based on their product characteristics and production scale.

As the food industry’s requirements for hygiene, safety, and automation continue to increase, cleaning equipment is also evolving towards more efficient, more intelligent, and more environmentally friendly solutions. In the future, new cleaning equipment integrating machine vision, intelligent control, and online monitoring technologies will offer greater opportunities for innovation in the nut processing industry.

For food processing enterprises, mastering the principles and maintenance points of cleaning equipment and establishing scientific operating procedures and maintenance systems are important foundations for ensuring product quality and improving production efficiency.

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