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What are the recommended pressure settings for pulsers (pulse meters)?
Pulsers keep blowing due to pressure.
How Pump Ratios Work
A pump’s ratio tells you how much it multiplies the air pressure. To find the fluid output pressure, multiply the pump ratio by the air pressure shown on the regulator gauge.
| Pump Ratio | Air Pressure | Fluid Output Pressure |
|---|---|---|
| 50:1 | 40 psi | 2,000 psi |
| 10:1 | 180 psi | 1,800 psi |
| 10:1 | 12.4 bar | 124 bar |
Piusi K400 Pressure Ratings
|
1,000 psi
Operating pressure
|
2,900 psi
Maximum bursting pressure
|
Note that a 50:1 pump at only 40 psi of air already produces 2,000 psi — twice the K400’s operating pressure. The bursting pressure is a failure point, not a working limit; always design around the 1,000 psi operating rating.
Recommended Pump Setting
To minimize the risk of damage to downstream components, set the pump to the lowest pressure that still delivers acceptable flow. A common recommendation is to maintain a 10:1 ratio at the pump.
To find the most air pressure you can supply without exceeding a component’s rating, divide that rating by the pump ratio. For the K400 (1,000 psi):
| Pump Ratio | Maximum Air Pressure to Stay at or Below 1,000 psi |
|---|---|
| 5:1 | 200 psi |
| 10:1 | 100 psi |
| 20:1 | 50 psi |
| 30:1 | 33 psi |
| 50:1 | 20 psi |
Why Pressure at the Meter Can Differ from the Pump
The pressure at the pump can be different from the pressure at the K400, depending on where the meter is installed and how the system is configured. While fluid is flowing, these factors reduce pressure along the line:
| 1 | Distance from Pump — The further the meter is from the pump, the more pressure is lost to friction and resistance in the piping or hose. |
| 2 | Pipe/Hose Diameter and Length — Smaller or longer pipes and hoses increase friction losses, reducing pressure by the time fluid reaches the meter. |
| 3 | Fittings and Valves — Fittings, valves, and bends in the system each cause additional pressure drop. |
| 4 | Fluid Viscosity and Temperature — Thicker fluid, often caused by cold temperatures, increases pressure drop across the system. Avoid raising pump air pressure in cold weather to compensate; that also raises the pressure the meter sees when flow stops. |
Protecting the K400
To keep the pressure at the K400 below its rating, and to maintain the meter’s integrity and accuracy:
| Limit air to the pump | Set the air regulator using the formula above so pump output stays at or below the lowest-rated component. This is the simplest and most effective control. |
| Install a fluid pressure regulator | A regulator installed directly before the meter holds pressure at the K400 within its limits, even when the pump runs higher to serve other outlets. |
| Consider a pressure relief valve | Fluid trapped in a closed line can build pressure as it warms (thermal expansion). A relief valve protects against this and against regulator failure. |
| Verify with a gauge | Don’t rely on calculations alone. A fluid pressure gauge near the meter confirms the actual pressure at stall. |
The maximum working pressure of each component in the system may not be the same. To reduce the risk of over-pressurizing any component, be sure you know the maximum working pressure of each component, including the air motor and pump.
Never exceed the maximum working pressure of the lowest-rated component in the system. Over-pressurizing any component can result in rupture, fire, explosion, property damage, and serious injury.
To determine fluid output pressure from the air regulator reading, multiply the pump ratio by the air pressure on the regulator gauge:
10 (:1) ratio × 12.4 bar air = 124 bar fluid output
Limit the air to the pump so that no air line or fluid line component or accessory is over-pressurized.