Hold this component in your hands as you read the following description.

Note: Maximum Regulator Operating Pressure is 145 psi or 1Mpa

The regulator controls the pressure within the pneumatic circuit. The pressure within the pneumatic circuit determines the force generated by the actuator. Higher air pressures requires more air to be forced into a given volume, therefore higher pressures affect the rate at which the stored pressurized gases are consumed.

As the pressure of a gas increases, the density or amount of gas per unit volume increases. The reservoir contains a finite amount of air at any given pressure. When the pneumatic circuit pressure is increased, stored air is consumed at a proportionally higher rate. The result is that increasing the pressure results in greater actuator force, but fewer actuator operations. The regulator allows the air pressure within the circuit to be adjusted to meet the performance requirements of the pneumatic system.

It is not always necessary for student engineers to operate the pneumatic systems at maximum pressure in order to ensure maximum performance. Well-engineered machines are optimized with respect to required force and air reserves. This is an engineering design challenge. Higher pressure means fewer cycles from the pneumatic cylinder.

One conclusion that might be drawn from this knowledge is: Do not set the regulator to maintain a pressure higher than what is necessary for the design function of a given mechanism. To do otherwise would result in an unnecessary depletion of stored air reserves.

Regulator Operation

The regulator controls and maintains the pneumatic circuit pressure. The regulator prevents both under pressure and overpressure situations. As pressurized air is consumed by the actuator, pressure on the downstream (circuit) side of the regulator drops. This drop in pressure creates an imbalance of forces acting between a tensioned spring and a pressurized diaphragm valve within the regulator. The imbalance causes the spring to open a valve connecting the circuit to the (higher pressure) air stored in the reservoir. As the higher pressure air flows from the reservoir, through the regulator and into the circuit, the circuit pressure increases. This increased pressure acts to re-establish the balance of forces between the spring and diaphragm within the regulator, and closes the valve connecting the reservoir to the circuit. (see Figure 2.1.18)

Download the Computer Based Learning Software found on the GEARS website by navigating to www.gearseds.com. Click on Support in the header and then click on Documentation. The file is named SMC Pneumatics Computer Based Learning Module.

Click on the link you find there, and follow the download and installation instructions.

Study the text and animations found in section 3.0 section of the SMC Computer Based Learning Software for the best explanation of the regulators operation.

Caution This is a 200mb file and requires a high-speed internet access for efficient download.

3/2 Solenoid Valve(see Figure 2.1.19)

Hold this component in your hands as you read the following description.

Solenoid Specifications

Voltage 12 volts

Power Consumption 1 Watt @ 42mA

Cv .008

This valve is a 3/2 (Read Three, Two) normally closed solenoid valve used to operate single acting pneumatic cylinders. (see Figure 2.1.20)

The designation, 3/2 refers to the number of ports (3) and the number of positions (2) or States of Operation of a pneumatic valve. (see Figure 2.1.21)

The first number (3) refers to the number of ports through which air can enter or leave the valve. Counting the ports or holes in the valve body is an easy way to determine the number of ports in a valve. The solenoid valve in the GEARS-IDS kit has three holes, or ports. These ports are labeled as follows:

P1 This is the Pressure Port. This is the connection port from the solenoid valve to the regulator or pressure line.

A2 This is the actuator port. This is the connection port from the valve to the pneumatic cylinder or actuator.

E This is the exhaust port. This is where the spent air is exhausted from the pneumatic cylinder or actuator to atmosphere.

OFF

This is the default mode in which the A2 actuator port is normally closed (NC) and the exhaust port is normally open. When the solenoid valve is not energized, it defaults to this mode or position. (NO).

ON

In this position solenoid is energized by an electrical current and a poppet valve within the solenoid body is opened. This closes the E (exhaust) port and opens the A2 (Actuator) port. The ON condition is maintained as long as the solenoid valve is energized. When power to the circuit is disrupted or shut off, the internal valve spring closes the A2 (Actuator) port and opens the E (Exhaust) port. This returns the valve to the default or NC state.

The solenoid valve is electrically actuated. When the valve is energized, a 12 volt 42mA (low amperage) current passes through a coil of wire within the valve. The electrical energy passing through the coil induces a magnetic field around the coil. This magnetic field draws an iron core into the center of the coil and actuates a poppet valve within the body of the solenoid valve. The poppet valve opens a path from the pressure port (P1) on the regulator side of the valve, to the actuator port (A2) on the pneumatic Cylinder or actuator side of the valve.

When the coil is not energized (The current to the coil is turned off), the poppet valve returns to a default position closing the connection between the pressure port (P1) and the actuator port (A2), and opening the connection between the actuator (A2) and the exhaust port (E). The pressurized air within the actuator passes back through the solenoid valve, and is exhausted into the atmosphere.

The solenoid valve can open or close a circuit pressurized to .8 MPa (116psi) within 3.5 ms. This is more than 10 times the stimulus response time of the average person.

There is little wonder why fast, effective industrial automation systems are the result of pneumatics coupled with microprocessors.