Downstream Injector Ratio Chart
Use this chart after measuring the injector's water-to-chemical draw ratio. It converts that ratio into chemical share and nominal outlet SH from a 12.5% pickup solution.
The stamped or advertised injector ratio is a starting reference. Hose length, nozzle, downstream pressure, solution properties and equipment condition can change actual draw.
Measured downstream ratio chart
| Water:chemical solution | Chemical share of output | Outlet SH from 12.5% pickup |
|---|---|---|
| 4:1 | 20% | 2.5% |
| 5:1 | 16.67% | 2.0833% |
| 6:1 | 14.29% | 1.7857% |
| 8:1 | 11.11% | 1.3889% |
| 10:1 | 9.09% | 1.1364% |
| 12:1 | 7.69% | 0.9615% |
| 15:1 | 6.25% | 0.7813% |
| 20:1 | 4.76% | 0.5952% |
The chart assumes the pickup container is 12.5% SH. If it contains a premix, use that premix concentration. The table is not a product-performance guarantee or a surface-treatment chart.
Final SH = pickup concentration × chemical parts ÷ (water parts + chemical parts).
Worked example
A measured 10:1 ratio means ten water parts for every one chemical-solution part, or eleven total parts. The chemical share is 1 ÷ 11 = 9.09%. With 12.5% SH in the pickup container, nominal outlet SH is 12.5% ÷ 11 = 1.1364%.
Measure the draw before relying on the chart
- Use the equipment manufacturer's approved draw-test procedure.
- Record the water output and the amount removed from the pickup container over the same test.
- Express those measured volumes as water parts to chemical-solution parts.
- Repeat the test after material changes to hose, nozzle, injector or operating setup.
If the approved procedure reports total solution output rather than water alone, do not label that number as a water-to-chemical ratio. Keep the ratio convention with the record so it can be entered correctly later.
Calculate another pickup strength
Open the Downstream Injector Calculator to enter any pickup concentration and measured ratio. Read Understanding Dilution Ratios if a manufacturer uses a different ratio convention.
Mathematical estimate only. Follow product labels, SDS, equipment instructions and applicable rules. Never mix sodium hypochlorite with acids, ammonia or incompatible chemicals.