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The Pioneer of Modern Leak Testing

Vacuum Decay Leak Testing Using a Self-Contained Vacuum Regulator

As we all know, the variety of application for leak testing is staggering. Every day more products are designed that require testing. Not all of them are suitable for the more common types of test; pressure decay, differential pressure and mass flow.

Some products need to be leak tested by subjecting them to negative pressure (vacuum).

This can complicate matters for some. The first problem: generate the vacuum needed for testing with the knowledge that vacuum pumps can be loud, messy and quite expensive.

The second problem: put all the needed components into one small enclosure that can be used on the bench or in an automated machine.

The SprintmD Solution

SprintmD-V has a built-in venturi vacuum generator to produce the negative pressure needed to leak test products subjected to low vacuum (typically in the 25 to 100 inches of water range).

Incorporating a negative pressure sensor, vacuum source, valving, and logic control, the Sprint mD-V handles the task of vacuum testing on the bench in a small enclosure, and without cumbersome vacuum pumps.

Sprint’s pneumatically-driven vacuum source means low noise, no heat, and no maintenance.  And because it is so small, it can be placed very close to the suction point.  NO added floor space is required because the vacuum source is right inside Sprint’s normal enclosure.

How SprintmD-V Works

SprintmD-V works like this:

Product is attached to the test port and the leak tester’s program is started.  (Figure 1)

Positive pressure is applied to the vacuum generator through valve V1.  The vacuum strength is set by the pressure regulator.

Vacuum is supplied to the test port through valve V2 from the vacuum regulator.

When the test reaches the programmed vacuum level, valves V1 and V2 close.

Negative pressure trapped between valve V2 and the product is measured by Sprint’s vacuum sensor S

If the negative pressure decays past the established set-point, SprintmD turns on its fail light and sends a signal to the I/O port.

Electrical Parameters

For testing larger products (greater than 1 liter), an external vacuum reservoir can be included in the test circuit.  The vacuum tank (typically about 2 liters in volume) is connected so that negative pressure is supplied to the reservoir (Figure 2).

When a vacuum accumulator is used, the vacuum generator generally runs continuously to maintain the vacuum reserve.

The vacuum tank makes it possible to test larger product without waiting for the vacuum generator to draw down the product to the desired vacuum during each test.

Other plumbing and valving arrangements are possible with the SprintmD-V


SprintmD-V is typically used to leak test rather small products (less than 1 liter) at a fairly low vacuum (under 100 inches of water).

Products often tested with vacuum include valves, vacuum chambers, vacuum control devices, and vacuum-operated mechanisms.

The SprintmD-V is also used to simulate normal-use conditions on other products that operate using vacuum or are subjected to vacuum.

Please contact Uson to find out how a Sprint vacuum tester can be applied to your testing needs.


  • Completely self-contained.
  • No vacuum pumps or extra sensors to buy
  • All components in one small enclosure
  • Fully calibrated and simple to maintain
  • Perfect for bench or automation
  • Bench or rack-mount enclosure
  • Small footprint of 8.5 by 14 inches
  • Resolution of negative 1/100 psi
  • User-Selectable engineering units.
  • Interface for statistical process control
  • The SprintmD-V allows the user to select vacuum units of psi, inches of water, millimeters of mercury or millibar.

For more information or applications advice contact me on 281-671-2000 or email

Joe Pustka

Director Applications Engineering

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