---
title: "Screw Conveyor Hopper Factory Acceptance Test: 7 Checks for Food Powders"
date: 2026-10-25T01:58:00Z
modified: 2026-10-28T02:21:00Z
permalink: "https://www.hyflowtech.com/blog/basic/screw-conveyor-hopper-fat-checklist/"
type: post
status: publish
excerpt: ""
wpid: 2631
categories:
  - basic
featured_image: "https://www.hyflowtech.com/wp-content/uploads/2026/10/image1-11.webp"
featured_image_alt: Technical blueprint illustration of an inclined screw conveyor hopper designed for food powders. The graphic outlines a Factory Acceptance Test (FAT) with text detailing 7 critical checks, featuring a conical hopper, an angled conveying tube, and a drive motor.
timestamp: 2026-10-28T02:21:00Z
tags:
  - basic
---

## **Quick answer**

A factory acceptance test (FAT) checks whether a screw conveyor hopper meets the buyer’s agreed specifications before shipment. The checks for food powders revolve around [cleaning](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/post/cip-cleaning-process-guide.md) access, materials, throughput, powder retention, documentation, and a few other factors. After each check, you’ll have a recorded result that you can compare with the acceptance criteria.

![Technical blueprint illustration of an inclined screw conveyor hopper designed for food powders. The graphic outlines a Factory Acceptance Test (FAT) with text detailing 7 critical checks, featuring a conical hopper, an angled conveying tube, and a drive motor.](https://www.hyflowtech.com/wp-content/uploads/2026/10/image1-11-1200x675.webp)

### **1. Do the Materials and Dimensions Match the Order?**

Comparing the finished machine with your purchase specifications and approved drawings can help you confirm this. The conveyor length and hopper capacity should be checked first, and then you should verify the drive arrangement and outlet position. For food-contact surfaces, make sure to review the available records to confirm the specified surface finish and material grade.

For example, HYFLOWTECH’s sanitary screw conveyor hopper comes with AISI 304 or 316L stainless steel for product-contact parts, with an Ra ≤0.8 μm polished finish. Buyers can also customize the conveyor length and hopper capacity through our [OEM services](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/page/oem.md). During FAT, check that the finished machine matches the material grade, surface finish, and dimensions specified in your order.

If any differences are spotted, they should be documented and corrections should be arranged before the check is approved.

### **2. Does It Deliver the Required Throughput Consistently?**

Your agreed throughput target should be met by the screw conveyor hopper while it maintains a steady flow. Checking this requires running the conveyor with your actual powder where possible. If that’s impractical, agree on a representative substitute and record any differences in its properties. Then run the test, collecting the discharged material over a measured period and weighing it to calculate the flow rate in kilograms per hour. Check consistency by repeating the test as required by your FAT protocol.

Look for powder piling up at the inlet or uneven feeding as the conveyor runs. At HYFLOWTECH, our screw conveyor hopper uses a variable frequency drive that allows you to test the screw speeds your production process needs. But keep in mind that screw conveyors move powder by volume, not weight. This means two powders with different bulk densities can produce different hourly weights at the same screw speed.

As such, the results should be compared with the agreed throughput target and tolerance for your test powder, rather than a generic capacity rating.

### **3. How Much Powder Remains After Discharge?**

You can check [powder](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/post/how-to-prevent-powder-bridging-in-hopper.md) retention by inspecting the amount of material left inside the conveyor and hopper after discharge.

Let the conveyor discharge as agreed and stop it safely once the test run comes to an end. Then inspect the bottom of the hopper, accessible screw surfaces, and the outlet. What you’re looking for is any bridging or compacted powder that may affect the next batch.

If your FAT protocol requires a numerical assessment, collect and weigh the accessible leftover powder using the agreed method. Then make a note of the areas that you’re unable to inspect without further disassembly.

HYFLOWTECH’s hopper minimizes leftover material using a low-residual design. Still, the amount of powder left behind has to meet the acceptance criteria agreed for your application.

### **4. Does Powder Escape Through Covers or Connections?**

This can be checked by looking for dust leaks as the machine runs with the agreed test powder. The hopper cover and discharge connection should also be inspected, with more attention paid to shaft-seal areas and joints. Powder escaping should also be watched for when the conveyor starts or stops.

If leakage is identified, record where it happens and what the machine was doing at the time. If a specific containment level is required by your plant, a suitable measurement method should be agreed on before testing. That’s because a visual inspection alone isn’t enough to measure airborne dust concentration.

### **5. Can Operators Reach and Clean Product-Contact Areas?**

Operators should be able to access and clean the required product-contact areas using the agreed procedure. Make sure to ask the manufacturer to demonstrate how to do this. Once the equipment is safely isolated, the hopper interior and conveying path, including the accessible seals and outlet, should be inspected.

The screw and discharge connections, where leftover powder may collect, demand particular attention. See which components or covers can be removed by operators. You should also consider whether they require tools and how everything will be put back together by the operators.

Cleaning access matters for a sanitary [screw conveyor](https://www.hyflowtech.com/product/sanitary-screw-conveyor-hopper/) when ingredients are changed, especially if the facility you operate handles allergens. The FAT can show you whether the necessary areas can be accessed by operators and whether they can follow the proposed cleaning procedure.

That said, passing this check doesn’t automatically prove that your plant’s residue limits will be met by your eventual cleaning process. You still have to verify this under the cleaning conditions of your particular facility.

### **6. Do the Drive and Safety Features Work Properly?**

The drive and safety features pass their FAT checks when they operate as specified in the approved design and test protocol. Run the [screw feeder](https://www.hyflowtech.com/product/semi-automatic-screw-dosing-machine-hopper-with-screw-feeder-system/) hopper through the required speed range. The screw should start and stop properly and respond well to speed adjustments. Also, check whether it runs without excessive vibration or unusual noises.

You’ll also want to inspect the protective devices and guards. Where required by the approved design, test emergency stops or interlocks following a safe procedure. If you ordered a mobile frame, check the stability of the machine and that its caster locks hold securely.

Record any failures and arrange corrections or retesting as required. Then, before signing off, compare the results with your approved specifications.

### **7. Are the Results Documented and Approved?**

The test results should first be reviewed against the original FAT protocol. The report should identify the test powder and equipment, along with the acceptance limits, operating settings, and measured results. Additionally, it should include inspection findings and any material or surface-finish records required by the order.

For anything that remains unfinished or any failed check, the issue should be documented and responsibility for correcting it should be assigned. Also, agree on whether you need another test before shipment. Make sure to follow the formal sign-off process in the purchase agreement instead of relying on verbal approval of the FAT.

 [ ![Stainless Steel Sanitary Screw Conveyor Hopper](https://hyflowtech.b-cdn.net/wp-content/uploads/2026/04/filling-hopper.jpg)

**Sanitary Screw Conveyor Hopper**

 This stainless steel screw conveyor hopper is an integrated feeding and conveying system designed for automatic and dust-free transfer of powders and granules.

 Explore Catalog 

 ](https://www.hyflowtech.com/product/sanitary-screw-conveyor-hopper/)

## **Does Passing FAT Mean the Hopper Is Ready for Production?**

Not yet. Passing the FAT means the hopper met the agreed checks under the conditions tested at the manufacturer’s facility. It doesn’t prove the machine will perform the same way once you connect it to your production line.

After installation, site acceptance testing (SAT) can check how the hopper works with your existing equipment and local utilities. You can also verify its performance under actual production conditions.

Keep your signed FAT report and outstanding-action list handy. They’ll show you what passed at the factory and what still needs checking before you put the hopper into service.

[ Contact US ](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/page/contact-us.md)