At Acro Associates, we rarely sell a valve off the shelf. We tailor and calibrate our pinch valves specifically to your tubing, flow, and control requirements. This level of service is achieved by routing inquiries to our applications engineering department. After receiving information about your application, our engineers collaborate with you to select the most appropriate model of pinch valve for your application and assign it a reference "Version" or "V" number, so that you can easily reorder.

Acro's commitment is to provide as much assistance as you need, from guiding you through the questions below to recommending a suitable pinch valve based on our understanding of your application. If you have any questions, please call us at 1-800-672-2276, or send us an e-mail at engrs@acroassociates.com.

The minimum information our engineers need to properly select a pinch valve is described below. After you define this information, you may convey it to us in a number of ways: by calling an Acro Applications Engineer at 1-800-672-2276; by e-mailing us at engrs@acroassociates.com; or by completing our Applications Review Worksheet and submitting it electronically or via fax to 925-680-8113.

REQUIRED INFORMATION FOR ALL VALVES

What is the application? — From this information, we gain an understanding of your system operation and performance requirements and allows us to draw on past experience to better meet your needs.

What is the O.D. and I.D. or wall thickness of the tubing? — This information helps us determine the most appropriate valve model and pinch gap.

What is the tubing material, durometer, and maximum media pressure? — These specifications establish the required pinching force.

What is the desired flow rate? — From this information, we can establish a total opening specification that permits adequate flow. (Often times, a qualitative answer to this question is sufficient.)

Is position feedback required? — This information allows us to establish whether a position sensor should be considered. The specific application details you provided above will enable us to determine a suitable sensing mechanism.

FOR PNEUMATIC VALVES

Supply the required information for all valves and answer the following additional question:

What is the available minimum and maximum supply pressure? — This is related to the maximum pinching force and ensures that the valve will be compatible with your existing hardware.

FOR SOLENOID VALVES

Supply the required information for all valves and answer the following additional questions:

What are the power supply voltage and current ratings? — These relate to coil selection, total opening, and pinching force, and enable us to design a valve that is compatible with your existing hardware.

What is the cycle rate and duty cycle? — These specifications help us design a valve that takes into consideration heat generation and the corresponding heat rise, which must be maintained at safe levels. Duty cycle is expressed as a percentage (%) and is determined by (ON time) / (ON time + OFF time). For example if a pinch valve is energized for 1 second out of 4 seconds, the duty cycle is 1/(1+3) = 1/4 = 25%.

What is the maximum on-time? — Very close attention must be paid to the maximum on-time data provided in conjunction with the duty cycle calculation to avoid overheating and eventually damaging the valve. The maximum on-time should take into account the time required to perform such operations as tubing changes or maintenance in addition to the actual application requirements.

Is a Pulse and Hold driver circuit available? — Pulse and Hold driver circuits add flexibility to the system by enhancing operational parameters and minimizing heat. If none is available, the valve must be designed accordingly.

Is noise a concern? — From this information, we can determine whether sound dampenening devices should be considered.