Options for Zaxis Testers
Downstream Release (aka Occlusion Release, Down-stream occlusion Release, Downstream flow release) – This option is a valve on a separate port. It is a leak tight valve. During the Test step of an Occlusion or Flow test, it will open. This will allow for a decay through the part and out to atmosphere. The valve should be selected so that its orifice is larger than the smallest diameter of the part. The goal is to make the part be the ‘choke’ in the system not the valve.
Downstream Sense – This option is a sensor that is placed in a separate port. It can be used as the test sensor or is most used as the event sensor for a Crack test. This sensor can be either pressure or flow.
Dual Fill – This option would use the pneumatics of a sequential. This is used if the customers part has multiple cavities connected by a small fill or tortured path. Dual fill would fill from both sides of a part, getting to final test pressure faster that filling from one side. During the test both channel valves would stay open.
Vacuum Vent – The standard vent step releases the test pressure through a valve to atmosphere. This option adds a venturi to draw the part to below atmosphere. This would be used of the customer needs to ‘pack’ the part or reduce the volume after test. Pneumatically this would look like a PV but not have the Vacuum test capability.
Vacuum Bypass – This option is used when the customer has purchased Type 2 valves or has the need for high volume flow during the fill step. This is a separate valve that is tapped to the test port internally. It is a leak tight valve with a larger orifice than going the standard route through the 3-way stem.
Vacuum Source Selection
Vacuum Source Selection (aka Switched Vacuum) – A venturi will only draw down to 90% of the atmosphere around it. If the customer has a deeper vacuum need, they will need to supply vacuum from a mechanical pump. This option has a switch the selects either the internal (venturi) or external vacuum supply. The external supply will enter through a separate bulkhead on the rear of the chassis.
Tank Saver Valve
Tanks Saver Valve – The manual regulators used in all units are a high precision, high bleed regulators. The bleed-off of output pressure allows the regulator to be faster responding and more accurate in its setpoint. If a customer needs to use a special test gas (nitrogen, helium, etc.) it will most like come from a finite source (tank or bottle). If the tester sits idle, this bleed will waste the tank air. The tank saver valve is installed internally between the inlet bulkhead and the regulator. In the de-energized state, it blocks the supply from reaching the regulator, blocking the bleed. The valve callouts on the tester will activate the valve for the Pre-Fill and Fill steps, returning to closed and saving the tank supply.
External Vent – Customers with a high amount of debris in the test volume would have to open the unit and clean the internal valves. For ease of cleaning the Venting valve is moved externally. This allows for easy access to perform the cleaning procedure.
Separate Fill & Sense
Separate Fill & Sense – For large test volumes, and to take full advantage of the electronic regulator, some applications have the need to fill and sense from separate ports. The separate port allows the sensor to monitor the filling pressure and feedback that information to the algorithm feeding the control of the electronic regulators output. This option can also be used to check for occlusion in a part while it is performing a pressure decay test. If the part has an occlusion, it will not reach test pressure.
High Bleed – Electronic regulators have a ‘sweet spot’ they like to function in. Typically, this is 40-90% of its range. They have a hard time at the lower 10% of the range. If a customer has test pressure needs at the top and bottom of the scale, the high bleed can be added. The high bleed valve is placed between the regulators output and the input of the test manifold. When active it allows a small amount of test pressure to be sent out to atmosphere. This causes the amount of pressure reaching the test sensor to be lower than needed. The feedback algorithm then will adjust the regulators out put higher to achieve the correct pressure. This causes the regulator to function higher in its scale to be able to adjust more easily. This option can also be used for customers with very low test-pressures.
Second Regulator – This option allows for two manual regulators to be fitted to the unit. The regulator to be used in the test, is selected by the test pressure value field. A value that is set in the Hyphen (hidden in the About screen) menu declares the switch point for the regulators. For example, is the switch pressure was 10psi. The external regulator would be used for all pressures above 10psi, and the internal regulator would be used for all pressure below 10psi.