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Impeller Recommender for Real Airstreams

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About This MicroSim

Ten job cards describe real airstreams, such as a boiler forced draft fan, cyclone exhaust, buffing threads and corrugated box trim. They appear in a shuffled order. For each card you recommend one of seven impeller types, each tied to a current Twin City Fan model:

Bin What it is built for
Airfoil (HAF) Hollow airfoil blades; highest efficiency; clean air, high pressure.
Backward curved (HIB) Single thickness curved blades; clean air or light dust loading.
Radial tip (RTF) Curved at entry, radial at tip; large volumes of clean or dirty gas.
Air handling radial (RBA) Heavy blades welded to back plate and front plate; relatively clean air, fumes, light contaminant.
Open radial paddle (RBO) Open paddles, no plates; coarse, sticky, heavy or abrasive material.
Back plate wool, material handling (RBW) Radial blades on a full back plate; long, stringy or fibrous material.
Paper handling (RBP) Full back plate with gussets and a deflector cone; paper trim, fibrous material, metal trim, high impact.

Some bins take more than one card, and you are not told how many. You get two attempts per card, and mastery is 8 of 10 correct on the first try. The bin descriptions and every job card come from the application statements on Twin City Fan's current product pages (retrieved 2026-10-08) and FanPedia pp. 31–32. Job settings such as "process tank" and "stamping line" are illustrative wrappers around those statements.

How to Use

  1. Read the job card. Each bin tile shows its description; press Bin descriptions (or D) to see all seven in full.
  2. Press the impeller you recommend (or keys 1–7). A correct choice shows "✓ Correct:" with the impeller and the catalog reason.
  3. A wrong first try shows "Not the best fit. Ask what the material does in this airstream: does it stick, wrap, strike, or pass through?" and the card comes back for a second try. A wrong second try shows the best fit and why, and the card counts as missed.
  4. Press Next card (or Enter). The status line shows "Recommendations correct on first try: n of 10", and "✓ Mastered" appears at 8 or more.
  5. After card 10, the summary lists every card with your first choice and the best fit. Press Start over to reshuffle the cards and reset the score.

Keyboard: keys 1–7 choose a bin, Enter goes to the next card, D shows or hides the bin descriptions. Tab also reaches every button.

Data label: "Source: tcf.com product pages, retrieved 2026-10-08; FanPedia pp. 31–32", shown at the bottom left of the drawing.

Iframe Embed Code

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<iframe src="https://moroshek.github.io/FanTASTIC-textbook/sims/ch09-impeller-recommender/main.html"
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Lesson Plan

Learning Objective

The learner will recommend one of seven impeller types for each of ten airstream descriptions, judged against Twin City Fan's catalog application statements, with at least 8 of 10 correct (Bloom: Evaluate, verb: recommend).

Audience

Adult professional development: new application engineers, sales staff, representatives and facilities staff.

Duration

10-15 minutes

Prerequisites

  • Chapter 9: airfoil impeller, backward curved impeller, high efficiency centrifugal fan, radial tip impeller, radial bladed impeller, air handling impeller, open radial paddle impeller, material handling impeller, paper handling impeller.

Activities

  1. Recommend (8 min): Work through the ten cards. Before each choice, say aloud whether the material sticks, wraps, strikes or passes through.
  2. Review (3 min): In the summary, find each first choice that missed and name the misconception behind it.
  3. Discuss (3 min): Why does the cyclone exhaust card go to the radial tip fan and not a radial bladed fan, even though both handle dirty gas?

Common Misconceptions Addressed

  • The most efficient impeller is always the best choice: the airfoil wins only for clean air; dirty, sticky or stringy jobs go to more rugged wheels.
  • Any radial bladed impeller handles any dirty airstream: the RBA, RBO, RBW and RBP each match a different material behavior.
  • Paper shreddings and corrugated trim need the same impeller: threads that wrap go to the back plate wool wheel; trim that strikes goes to the paper handling wheel.
  • Radial tip fans are only for clean air: the catalog lists them for large volumes of dirty gas, such as incinerator induced draft and cyclone exhaust.

Assessment

  • First-try score shown as "Recommendations correct on first try: n of 10"; mastery is 8 of 10 on the first try, shown as "✓ Mastered".
  • Reading the bin descriptions before committing is exploration, not evidence.
  • Follow-up question: a customer needs to exhaust lint-laden air from a textile dryer. Which impeller would you start with, and what would you ask first?

References

  1. Twin City Fan & Blower product pages - Radial Bladed Fans (RBA, RBO, RBW, RBP) and Radial Tip & High Efficiency Fans (RTF, HAF, HIB): the application statements every card and bin is based on.
  2. FanPedia: The Fan & Blower Encyclopedia (PDF) - Twin City Fan & Blower; pp. 31–32 describe the centrifugal and radial impeller types.
  3. Chapter 9: Impeller Construction and Material Handling - the sections "Clean-Air Impellers Built for Efficiency" and "Impellers for Dirty Airstreams".