Combining the characteristics of pinch valve fluid separation and proportional valve control, the Miniature Proportional Pinch Valve (MPPV) introduces a whole new level of performance and efficiency to sanitary applications requiring cleanliness and sterility, as well as highly accurate incremental flow regulation. Eliminating the need for multiple-valve, high-maintenance assemblies, this single valve offers a compact, efficient solution.

The purpose of this eBook is to introduce readers to this new Miniature Proportional Pinch Valve technology and the advantages it offers.

Topics include:

• Development of the Patented Technology

• Control Requirements

• Meeting Sanitary Requirements

• Improving Process Efficiency

• Simplifying Maintenance and Reducing Costs

• Applying the Benefits to Your Design

Our overview of the MPPV begins with a look at the patented design behind this innovative valve.

Preserving the integrity of a fluid passing through a non- contact system is essential in a variety of sanitary applications. Ever-increasing levels of sophistication in new technologies have led to more stringent performance demands, and processes need to be regulated with greater speed and accuracy. Needle valves have excellent fluid metering characteristics but poor fluid separation characteristics. Conversely, pinch valves have superior fluid separation characteristics but inadequate fluid metering ability. In order to meet application requirements, these two types of valves would typically be used in tandem.

On 10-31-2017, Resolution

Air, Ltd. was issued U.S.

Patent No. 9,803,754 by the

U.S. Patent and Trademark Office.

Recognizing the need for a better approach, Resolution Air, Ltd. Founder and Senior Design Engineer, Brad Thompson set about developing a hybrid valve combining the fluid metering characteristics of the needle valve with the fluid separation of the pinch valve. This hybrid valve, the Miniature Proportional Pinch Valve (MPPV), was developed to deliver tight specifications for high-resolution flow control. The MPPV series can be integrated into portable and handheld equipment in a variety of key industries, including life sciences and medical devices, food and beverage, and healthcare.

The MPPV pinches a fluid-filled, low durometer tube effectively varying the orifice size to regulate the flow of the fluid (liquid or gas) through the tube. The design incorporates a stepper linear actuator (stepper motor and lead screw) and a custom piston in a miniature aluminum valve body.

Using stepper motor linear actuator technology, the MPPV achieves .0005”/step linear travel, high sealing force, low power consumption, and a non- backdrivable lead screw.

The bi-polar stepper motors used in the Miniature Proportional Pinch Valve require two input control signals, a step signal and a directional signal.

Step Signal - A Pulse Width Modulated (PWM) signal, Each pulse generates a single step. For the MPPV-series, a single step equates to 7.5 degrees of motor rotation. Since the motor shaft is coupled to an integral leadscrew, this rotation translates into .0005”/step of linear motion.

Direction Signal

A digital binary signal which determines the clockwise /anti clockwise motor rotation.

There are two primary methods for generating and amplifying step and directional control signals.

PLC Based Control System

Signals generated by a Programmable Logic Controller (PLC) are amplified by a Bi-Polar Chopper Driver (DRV-1) to the level required to drive the motor.

Bi-Polar Driver/Controller System

The step and direction signals are generated and amplified by a single control device known as a Bi-Polar Driver/Controller.

The lightweight, compact MPPV series features an anodized 6061 aluminum body standard, with custom body materials available. Designed for low energy consumption, the MPPV series controls gasses or liquids with comparable linearity.

The design of the proportional pinch valve is groundbreaking, in part due to the ease and simplicity it brings to applications involving the transfer of highly pure liquids. Our next section considers the sanitary requirements met by the MPPV.

In life science, biotechnology, and pharmaceutical applications, tubing for transferring ultra-pure liquids, air, or other gases in manufacturing processes have demanding certification and testing requirements. The type of tube used in a given application is often dependent upon specific industry standards and certification requirements such as:

The MPPV hybrid valve technology is ideally suited for use in industries with rigorous standards because the design of the valve prevents the metered fluid from coming in contact with the valve.

In addition to certification, system pressure and chemical compatibility must be considered in the tube selection process. A resilient tube, such as platinum cured silicone, serves as a good launching point for many applications, with a range of 50-65 Durometer, Shore A. A knowledgeable and experienced tubing supplier can offer users guidance in selecting the appropriate tubing for an application.