Prune Four-Lane Weight Sorter

1. Background: Growing Pains Behind Rapid Expansion

Chengdu Xinhongyang Agriculture Co., Ltd. was established in January 2015 and is located in Pengzhou City, Chengdu. The company operates a 10,000 m² cold-chain distribution center, integrating fruit/vegetable procurement, pre-sorting, processing & packaging, and cold-chain logistics.

As the business scaled up, the owner Mr. Wu identified a critical problem: the original rough production model had high labor intensity and low efficiency. From variety selection to planting to final sorting, there was no unified standard.

"This made it difficult for consumers to choose and caused confusion at the sales end." — Mr. Wu

Over 100 workers manually sorted prunes by sight and feel — not only inefficient, but also highly inconsistent. Batches came out with mixed sizes, leading to frequent returns from premium supermarket channels and damaged brand reputation. Mr. Wu knew he needed automation, but he never expected the upgrade path would start with a costly detour.

2. The Pitfall: First 5 Tons of Fresh Prunes Scrapped

Before contacting FstSort, Mr. Wu tried a diameter roller grader from a domestic brand.

The logic seemed sound: prunes and plums are similar in size, and roller graders are simple and affordable. But the actual production result was a disaster —

Prunes are thin-skinned stone fruits. The roller grader's gaps frequently jammed fruits, and the mechanical friction during conveying and grading caused extensive scratches and bruises on the skin. The first trial run of 5 tons of fresh prunes came out badly damaged — completely rejected by supermarket standards.

"The pressure was enormous. Nearly all 5 tons were scrapped, and the delivery deadline for the season was approaching fast. If we couldn't find a working machine, this season's business would be ruined."— Mr. Wu, recalling the desperate situation

This failure taught Mr. Wu a crucial lesson: prunes cannot be sorted like ordinary plums. Roller graders rely on fruits "squeezing" through gaps of different diameters. This works for hard-skinned fruits (apples, oranges), but for thin-skinned prunes, more mechanical contact means more damage.

The loss wasn't just the cost of 5 tons of fruit — it was a whole season's time window.

3. The Turning Point: FstSort Engineers Came On-Site with a Weighing Module

Right at this critical moment, Mr. Wu contacted FstSort. Instead of pushing a sale, our engineers brought the weighing module and went directly to his facility with prune samples.

Our core assessment was based on two points:

First, prunes are suited for weight-based sorting, not diameter-based. Like plums, prunes have consistent flesh density, so weight is highly correlated with size and maturity — the most reliable grading indicator. Weight sorting is also more accurate for irregularly shaped prunes, avoiding misclassification caused by elongated or flattened shapes.

Second, our cup-carrier weighing system completely eliminates scratching. Each prune is carried by an individual soft cup throughout the weighing process, never touching any hard mechanical structure — only the soft cup. This is fundamentally different from the "hard-on-hard" contact of roller graders.

The on-site test results were a relief: prunes passed through the weighing module with their skin perfectly intact.

After detailed technical discussions and layout planning, Mr. Wu purchased four four-lane weight sorters at once.

4. The Solution: Full Line Configuration and Key Features

The complete line consists of:

• · Elevator → gentle fruit feeding, avoiding impact damage

• · Roller inspection table → manual removal of defective fruits and foreign matter

• · V-belt conveyor → single-file transport, ensuring each prune enters the weighing section independently

• · Four-lane weight sorter → core equipment, independent weighing with ±2g accuracy

• · Packing tables → direct bagging or boxing at each grading exit

Key Technical Features:

• · Cup-carrier weighing system — each fruit in a soft cup, zero friction, no scratches

• · High-precision sensors — ±2g accuracy, far superior to manual grading

• · Multiple grading outlets — configurable 9~16 exits for fine grading to export standards

• · Quick recipe change — switch between prune, plum, and other fruits in 3 seconds

• · Modular design — easy maintenance, any general electrician can handle daily care

  

For detailed specifications, please refer to the Plum Weight Grader Product Page→

5. Results: From "5-Ton Loss" to "50% Labor Savings"

After the first month of operation, the comparison speaks for itself:

"Now the entire process — washing, sorting, and packing — runs smoothly on the line. The system automatically identifies fruit weight and size, greatly improving efficiency. We no longer need every worker to be highly skilled. Over 50 people can now handle the workload that previously required over 100 — saving 50% on labor costs. With these four prune sorting lines, we ensure uniform size and stable quality, delivering higher-quality products to our customers. We believe that improved product quality will win us more customers. "— Mr. Wu, Chengdu Xinhongyang Agriculture Co., Ltd.

ROI Payback: Based on labor cost savings alone, the equipment investment pays for itself within the first year.

6. Why Prunes Must Be Sorted by Weight (A Peer Advisory)

Many prune processors ask: why can't we use a diameter grader? Our answer is based on real, painful experience:

Bottom line: Prunes are not apples. Diameter graders may work for hard-skinned fruits, but for thin-skinned prunes, they are a disaster. Weight sorting is not an "upgrade option" — it is a "must-have."

If you are also struggling with high prune sorting damage rates and rising labor costs — take a page from Chengdu Xinhongyang's book. Let our engineers bring the weighing module to your facility, test with your actual prunes, and see the zero-damage sorting results with your own eyes. We can also provide a custom line layout and ROI analysis based on your capacity and facility space.

👉🏻See more of prune sorting line→