---
title: "Can velocity"
description: "Can velocity (also upward can velocity or interstitial velocity) is the upward gas velocity in the space between filter bags inside a baghouse compartment. It is calculated as the gas flow into the compartment divided by the open cross-sectional area between bags (compartment area minus bag-and-cage area)."
canonical_url: "https://sylio.co/glossary/can-velocity"
last_updated: "2026-06-28T02:29:24.729Z"
---

**Can velocity** (also *upward can velocity* or *interstitial velocity*) is the upward gas velocity in the space between [filter bags](/glossary/filter-bag) inside a [baghouse](/glossary/baghouse) compartment. It is calculated as the gas flow into the compartment divided by the *open* cross-sectional area between bags (compartment area minus bag-and-cage area).

## Why it matters

Cake released from a bag during cleaning falls vertically into the hopper. If the upward can velocity is too high, the falling cake is re-entrained back up onto adjacent bags, defeating the cleaning cycle and raising [differential pressure](/glossary/differential-pressure-baghouse). Typical design limits:

<table>
<thead>
  <tr>
    <th>
      Cleaning system
    </th>
    
    <th>
      Max can velocity
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <a href="/glossary/pulse-jet-baghouse">
        Pulse-jet
      </a>
    </td>
    
    <td>
      1.5–2.5 m/s
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/glossary/reverse-air-baghouse">
        Reverse-air
      </a>
    </td>
    
    <td>
      0.6–1.0 m/s (compartment offline during cleaning, so the limit applies only between cleans)
    </td>
  </tr>
</tbody>
</table>

## Relationship to A/C ratio

Can velocity rises with [air-to-cloth ratio](/glossary/air-to-cloth-ratio) and falls with bag spacing. Designers tune both together: a high A/C only works if bag spacing is wide enough to keep can velocity in range.

## Related terms

- [Air-to-cloth ratio](/glossary/air-to-cloth-ratio)
- [Baghouse](/glossary/baghouse)
- [Filter bag](/glossary/filter-bag)
- [Pulse-jet baghouse](/glossary/pulse-jet-baghouse)