Pneumatics & Hydraulics

For more energy-efficient pneumatics, 4 is greater than 7

April 2022 Pneumatics & Hydraulics

OEMs traditionally design their pneumatic machinery and equipment for an operating pressure of 7 bar. However, by reducing this to 4 bar, end users can cut their energy costs by up to 29% in some instances, creating a powerful USP (unique selling proposition) for the OEM. To help achieve such a desirable outcome, increasing numbers of OEMs are engaging with SMC’s team of experts, which can offer both the know-how and products to turn this concept into reality.

The shift to 4 bar standard operating pressure is already taking place at some large manufacturing companies. While not seeing mainstream adoption just yet, SMC believes it will become standard practice in the not-too-distant future as regulations tighten and public pressure for more energy-efficient industry grows.

With this thought in mind, OEMs must begin preparing for a 4 bar landscape. By making the transition now they can become industry pioneers, not only helping to capture a larger share of a rapidly emerging market, but significantly boosting their corporate image. Sure enough, while this task may at first appear daunting, working with the right technology partner can help ensure a painless changeover.

Although the vast majority of machine components will still perform at 4 bar, a close eye should, of course, be kept on some of them to ensure they operate as intended.

Actuators: pushing ahead

When designing a machine from scratch, it makes sense to start with the components that do the work: the actuators. In general terms, these are the elements that may not perform at their best, or sometimes not at all, using lower pressure.

Two variables are key: force and speed. In the majority of horizontal applications, actuators operate at lower supply pressure because they are only acting against friction, not force. As a result, it’s normal to size actuators for use in horizontal orientations to perform at a certain speed.

In vertical applications, however, the story can be different as the cylinder pressure has to overcome the load pressure. These applications tend to be more critical and usually demand specific considerations to ensure the actuator meets its intended objective. Reducing the pressure to 4 bar in vertical applications may require the use of a larger-bore actuator to ensure the required force. If using a larger bore size is an issue due to lack of space, SMC’s VBA-Series pressure boosters can provide the required pressure level in that local part of the application without having to increase the main line pressure, making it possible to use the existing actuator size.

In either case, a simple calculation can indicate the theoretical force of the cylinder: F = P x A, where F is force in Newtons, P is pressure in bars and A is the effective area of the cylinder bore in square centimetres. As a point of note, if working at 4 bar demands a larger bore size, the saving in air consumption will offset any additional cost.

One challenge that could arise is that of space. What if a cylinder with a larger bore will not physically fit with your designated design space? Here, scrutiny is required to select a supplier that can provide compact and lightweight actuator solutions. SMC offers more compact cylinder solutions than its competitors. These products also feature a lower minimum operating pressure and a number of energy-saving concepts.

The other option is to use a different technology, such as a double-force cylinder. Again, tapping into the expertise of a reputable pneumatics supplier will prove useful in specifying the optimal solution.

Valves: take control

It’s not really high or low pressure that controls actuator speed, but the flow of air it receives. If you need higher speed, the valve will control that for you. With the cylinder bore and force defined, it’s possible to select the valve size. SMC offers directional and process valves with the lowest power consumption, making them ideal for use at 4 bar.

Blowers and vacuum units

When it comes to blowers and vacuum units, higher pressure does not mean higher performance, but quite the opposite, which is why a product like a high-efficiency nozzle has the potential to deliver notable gains. This solution can maximise air blow efficiency thanks to a more focused blowing impact. Indeed, governed by the Bernoulli effect, air blow thrust can be improved by 10%.

Experts at SMC recently saw this in action at a customer producing liquid detergent. The company’s bottle un-scrambler machine housed 25 air nozzles from an SMC competitor, costing a significant sum in annual air consumption. After application analysis, SMC recommended that the customer adopt its high-efficiency nozzles. These products could provide the same blowing performance (flow and impact force) but with a smaller nozzle diameter, thus allowing lower inlet pressure. Reduced air consumption led to healthy cost savings, delivering amortisation in just 1,57 months and the same replacement process performed on six more lines further boosted total annual cost-cutting.

SMC’s firm commitment to 4 bar is also visible with its vacuum units, which actually function at their best (maximum efficiency) when using low operating pressure. At 4 bar, the company ensures the vacuum pressure necessary to hold the component or product securely. Beyond this pressure, air (and money) is simply wasted and the vacuum unit loses efficiency. By turning up the pressure, you are not getting more force or speed, just more inefficiency.

Regulate to accumulate

As regulators handle point-of-use pressure, they can be good collaborators in the 4 bar journey, largely because they can be used to reduce the pressure even further at points where it’s possible. This might include air blow or vacuum applications, endowing the machine with even more energy efficiency. Every little bit helps.

Monitoring the pressure

Although a pressure switch plays no direct role in the 4 bar concept, it can prove beneficial in the long run. For instance, when designing a machine for 4 bar, you need to monitor pressure as the margin is low. In the first instance, pressure monitoring acts as a control measure for the machine to receive the 4 bar it needs. Secondly, pressure switches can monitor air consumption and identify any pressure losses. Air leakage is something that no machine can afford, especially at 4 bar.

The 4 bar future

OEMs should propose that end users adopt machinery which operates at 4 bar in order to stay competitive. To help expedite a project that involves designing a machine for this operating pressure, SMC’s expert team can deliver the optimal outcome for both OEMs and end users.

Through early project engagement, the correct sizing can be provided for each pneumatic component to ensure it consumes less energy without compromising machine performance. In addition, SMC can deliver solutions with minimal impact on surrounding or connecting components, thus avoiding any unnecessary time and cost for redesigns. Retrofit projects also benefit from this approach.

Amplifying the benefits

SMC’s ZH-X185 air amplifier multiplies air blow/suction by four and three times respectively. The upshot is that you can save up to 70% in air consumption through the ability to reduce input pressure, without any compromise in results. In fact, SMC says the ZH-X185 outperforms alternative products from other suppliers, typically by around 20%.

An air amplifier has many uses, such as blowing away machining chips and water droplets. In suction applications, the device can collect dust/powder when performing resin part marking and transfer or relocate loose items such as pellets in material handling tasks. The ZH-X185 is maintenance-free, easy to use and safe.

Importantly, an air amplifier can provide the solution to a number of everyday workshop challenges, such as where an existing device has insufficient blow, where high air consumption is proving costly, or where air flow is too slow. In instances such as these, it can be tempting to simply turn up the pressure, but this, of course, comes at a price. The reality is that a cost-effective alternative exists wherever you require a bigger output: an air amplifier. Although this solution is often not considered, it should be, because it can bring about notable savings.

It’s worth pointing out that the ZH-X185 is also a good solution for use in potentially explosive (ATEX) environments, as the product is entirely air-driven (no electricity required). In fact, the only type of application not suitable for an air amplifier is where extremely clean air is necessary, since the device uses surrounding air to amplify.

In relation to their impact in reducing energy costs, air amplifiers are not expensive devices, as evidenced by one major brewery (the name and location of which are not printed here in the interest of anonymity). The brewery’s bottling line was suffering from an inability to consistently adhere labels due to wet glass. However, by adopting the ZH-X185 it was possible to blow-dry the bottles sufficiently to allow proper label adhesion. Along with a much-improved process, ROI (return on investment) was achieved in just seven and a half months thanks to annual savings in air consumption. The brewery is also enjoying improved safety and simplified maintenance.

An alternative approach is to use a common air nozzle, which can sometimes be the right fit in applications where a high peak pressure is required. With an air amplifier, the output pressure is lower but the volume of air is higher to achieve a similar result. Most importantly of all, an air amplifier needs less pressure to achieve the same air flow, allowing the customer to reduce air consumption and enjoy the energy savings that come with generating less compressed air.


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