In this section, we will review the different components that manifolds use to enhance function and purpose. 

Built-in Power Savings Circuit

If the designer expects the solenoid valves to be continuously energized for extended periods of time, we recommend to use valves with power saving circuits to minimize the amount of heat released by the coil.

Plug Connector with Light/Surge Voltage Suppressor

Using the incorporated LEDs and plug-in option for media isolation valves integrates the electrical harness directly to the solenoid valves. This cleans up the assembly and reduces the cost of each valve termination. LEDs serve as a great feature, and their plug-in connections are our default on all new designs.

PNEUMATIC VALVE BASICS

Two of the most common designs for pneumatic control valves are the poppet and the spool. A poppet valve consists of an orifice that is opened and closed by raising and lowering a sealing surface onto the orifice. It usually has an internal spring that holds the valve in the closed position. When the spring force is overcome, the sealing surface lifts off the orifice and the valve opens. A spool valve consists of a shaft with a series of O-rings inside of a barrel. As the shaft moves back and forth, the O-rings shift position to open and close different flow paths.

Both valve types can be manifold mounted and valve manufacturers have standard valve manifold designs for mounting pneumatic valves (Both solenoid and air piloted) onto multi-station manifolds. When designs call for valve flow to interact with each other it is common to use pneumatic valves on custom bonded manifolds.

Here are a few key concepts that describe important characteristics of pneumatic valves:

Direct Acting Solenoid Valve: Direct-Acting Solenoid Valves utilize the force generated by the magnetic field of the solenoid to operate the valve. There is no minimum pressure required which makes them also a great choice for low pressure and vacuum applications. When the electrical current is removed, a mechanical spring returns the valve to its original position.

Indirect Acting Solenoid Valve: To conserve power, indirect or pilot assisting solenoid valves utilize air pressure to shift the valve. They often use a miniature 3-way solenoid valve vs a bigger valve solenoid and can operate at very low wattage draw. In doing so it limits the valves minimum operating pressure to approximately 20 psi and therefore not suitable for low pressure or vacuum applications

DIGITAL VALVES

Digital valves generally have an "on-off" style switch with digital readouts and other capabilities. Several manufacturers market manifold mount valves in sizes as small as 5mm in width and with various flow rates.

PROPORTIONAL VALVES

Unlike digital valves, proportional valves provide air or gas flow control. They vary the output flow based on the current or voltage input to the solenoid.

For example, most tires are tested to 1x10^-5atm-cc/s, units commonly seen from a high vacuum helium leak detector. On an air pressure decay style leak detector, the equivalent leak rate would typically be stated as 0.0002 sccm. And a bubble leak test would take 10 minutes before the first bubble would escape to the atmosphere.

Low leak valves feature large cross sectional O-rings, minimal leak points, and proven poppet designs. All mounting hardware is outside of the flow path and no internal parts are threaded during assembly to reduce the possibility of contamination.

MANUAL REGULATORS

Often an application requires a regulator to obtain a lower pressure circuit. Manifold mount is a convenient location to control the pressure. There are a few manufacturers that meet the criteria we look for in such regulators; size, accuracy, repeatability, flow, low leakage to atmosphere, manifold sealing surface and cost.

Single valve models achieve excellent results in dynamic applications like control of carrier gasses, blanketing gasses or dynamic dispensing applications with the phenomenal high resolution, high accuracy, and repeatability.

PROPORTIONAL ISOLATION VALVES

There are a limited number of manufacturers of proportional isolation valves for direct manifold mounting. Manifold mounted with zero dead volume, this valve design is ideal in critical applications for liquid and gas delivery, medical and analytical applications requiring ultra fine resolution and excellent repeatability.

Users mark positive displacement pumps as the clear choice when trying to design compact, multi-pump fluidic assemblies. As these can be mounted onto manifolds, this style of pump will often be more precise than a syringe pump without the expense of replacing a syringe. Available in a variety of sizes, they correlate to the volume of fluid that is drawn into the pump and then dispensed.

Other considerations to take into account when selecting a pump style:

• Flow rate
• Pressure
• Wetted materials
• Fluid pulsation
• Dispense volume
• Accuracy and precision needs
• Cycle lifetime requirements

Users can configure displacement pumps easily to optimize the most important aspects of the system’s fluidic requirements. The broad range of pump volumes along with the ceramic piston and pump head options provide many opportunities that can increase a manifold’s function.

Air displacement pumps and auto-pipettors are used for aspirating and dispensing samples with zero carryover. They are a great choice for benchtop instruments that work with disposable tips. Many customize these further for modular designs that accommodate a wide variety of pipette tips, tip adaptors, liquid level sensors, and pneumatic valves.

Additionally, their compact and lightweight nature allow them to mount directly on most small robotic workstations. This, in turn, makes auto-pipettors suitable for OEM instruments and production line operation.