October 2019 Design Notes

Adsorber filters protect against harmful condensation

Water in the oil is a serious issue for many hydraulic systems, because it can lead to increased wear and leakage. Adsorber filters which prevent moisture ingress via the tank breather system provide a remedy, according to engineers at Hansa- Flex, Bremen, Germany.

Unfortunately, although these filters can prevent serious damage and high costs, few systems are equipped with them. Operators often mistakenly assume that they don’t need protection against condensation, explained company officials. The fact is, if there is too much water in hydraulic oil, the system is subjected to a number of negative factors: condensation in the oil tank leads to premature aging, for example through hydrolysis. In addition, water attacks metallic surfaces and releases particles that can damage hoses and other components. Seals can also swell or shrink on contact with water and, in turn, permit leaks. Shorter maintenance intervals, high repair requirements and longer downtimes are the result.

Water can enter a hydraulic system in various ways. New oil, for example, may have a higher-than-recommended water content. Moisture can also enter the system through the rod seals of a cylinder. But what many people don’t realize is that the most common entry point is ventilation. Air can hold a sizeable amount of water vapor and it is sucked directly into the tank via the ventilation filter or breather. When the air cools, the moisture it contains condenses on tank surfaces. And because the so-called “dew point temperature” at high humidity is close to the initial temperature, even a slight drop in temperature in the tank is sufficient for condensation to form on the walls and cover. Such temperature fluctuations are a daily occurrence in some systems. The dangerous result quickly becomes visible in the form of droplets and rust.

The filters come in many versions to suit wide-ranging applications and can be retrofitted without the need to modify the hydraulic system.

Adsorber filters are the answer

Adsorber filters can close the access point for moisture that enters the oil via the ventilation system. They are installed on a tank and replace the conventional ventilation filter. Air is drawn in through the cylindrical adsorber filter. Any moisture is absorbed by the silica gel drying agent and bound by its dry granulate. In addition, the integrated 3 µm filter element removes all harmful particles and is the last element before air flows into the tank. The resulting relative humidity is a mere 10%. This lowers the dew point temperature to such an extent that there is no condensation in the tank even with significant temperature fluctuations.

The silica gel has another practical feature: when saturated, it changes color from orange to green — starting at the bottom of the adsorber filter. When the color changes from the top, moisture is absorbed from the inside of the tank and the unit achieves effective dehumidification. If the entire adsorber filter is green, it has reached its maximum capacity and must be replaced. A regular visual inspection of the filter is therefore sufficient to ensure that it functions correctly. Adsorber filters also have the advantage that they can be retrofitted without the need to modify the hydraulic system. The work merely requires dismantling the ventilation filter and installing the adsorber filter.

Recommended applications

Adsorber filters protect hydraulic systems from condensation damage, extend maintenance intervals and reduce the risk of unplanned downtime. However, not all systems require dehumidifiers. The environmental conditions are the deciding factor: the warmer the ambient air, the more water it can absorb and then release when it cools in the hydraulic system. Wherever things get hot — for example in tire and roll-material production facilities or foundries — the risk of water damage increases.

The same applies to environments with high relative humidity such as lock drive mechanisms on canals, sewage treatment systems, hydraulic tanks on ships or hydraulic systems in hydroelectric power stations. This is because even small temperature fluctuations are sufficient to trigger condensation.

Regardless of relative humidity and high ambient temperature, strong temperature fluctuations present the greatest potential for damage. If a system is regularly exposed to a temperature difference of 10° C (18° F) or more, condensation will inevitably occur in the hydraulic tank. Particular care must also be taken when using organic oils. These biodegradable fluids have a strong waterattracting (hygroscopic) effect and therefore absorb humidity from the air via their surface even without condensation. The use of an adsorber filter on hydraulic tanks with organic oil is therefore highly recommended.

HANSA-FLEX offers adsorber filters to suit many different systems. These range from inexpensive disposable filters, to refillable adsorber filters with valves for long maintenance intervals, to special designs that meet ATEX 2014 specs or comply with other industry and government regulations.

The optimal solution depends on many different factors. HANSA- FLEX application engineers have, thus, developed a checklist for determining the correct adsorber filter. Numerous components are also available for mounting the filters, including flange adapters, wall brackets, adapters for the simultaneous operation of secondary filter systems and oil-droplet separators.

Adsorber filters from HANSA-FLEX keep water vapor out of hydraulic tanks. Silica gel absorbs moisture and the filter changes color to indicate it has reached maximum capacity.

Pneumatic valve ensures noise-free,discreet breast pump design

Emerson ASCO series RB miniature valve, which the manufacturer customized for Babyation

The breast pump’s last significant redesign was in 1956, the year Elvis Presley released his first single.

That changed in 2015 when, while on vacation, Samantha Rudolph read The New York Times blog article that asked, “Shouldn’t the breast pump be as elegant as an iPhone and as quiet as a Prius by now?”

Although she and husband Jared Miller hadn’t yet started a family, she imagined the discomfort of being hooked up to a noisy and unwieldy machine.

Miller recounted that she turned to him and said, “Women deserve so much better than this.”

The couple worked nights and weekends to develop a new design. Rudolph, who was working as an executive consultant, read medical literature and interviewed moms to pinpoint what would make the pumping experience significantly better.

She and Miller, an electrical and systems engineer, designed a prototype that eliminated the device’s hallmark bulky bottle attachments and loud noises so women could pump discreetly, quietly and comfortably.

A key component that enabled the new product, called The Pump by Babyation, is a pair of valves that controls the vacuum function. Solenoid valves on older breast pumps are noisy; the couple realized that in order to fundamentally change the pumping experience they needed to find a silent valve.

Pumping new life into an old design

Sourcing a valve proved to be a challenge. For its initial trials, Missouri-based Babyation experimented with a wide variety of valves from several domestic and international sources. Some valves were too loud, others too expensive and some didn’t meet the need for a long life cycle.

Then Miller reached out to Emerson’s ASCO medical team to solve the start-up’s dilemma.

“We understood how important it was for Babyation to source a silent valve — without delaying its tight production timeline,” Emerson Business Development Manager David Wyandt said.

The Emerson team recommended series RB miniature valves, which offer a compact, lightweight design suitable for portable medical devices. The series RB valves are typically used in applications like respiratory therapy instruments, patient monitoring equipment, compression therapy (DVT), and robotic pharmacy dispensing — just to name a few.

Miller noted the series RB met the company’s specs for cycle life, a feature some competitors couldn’t match. It’s rated up to 10 million cycles, a lifespan that well exceeded The Pump’s needs.

“We didn’t want a product that had a limited shelf life. We’re building a premium product. We didn’t want to worry about failures in the early stage, so we wanted something that was well oversized for the life cycle,” Miller said.

The valve’s small footprint also allowed Babyation to incorporate it without altering the device’s housing. The result was a consumer-friendly product weighing under 5 lb, about the size of a small purse.

Despite its compact size, Emerson’s valve solution provides a high flow rate — up to 4 lpm — needed to pump efficiently. In addition, it consumes less than 1 W, preserving the product’s battery life.

Emerson’s solution proved more costeffective than competitors’ valves as well, allowing the startup to develop a premium product designated as a Class II medical device while keeping costs in check.

Powered by Emerson ASCO valves, The Pump by Babyation is quiet and discreet, allowing women to pump in places they might have avoided with traditional pump designs.

Collaborating to build a product that delivers

Babyation’s aspiration to create a reimagined pumping experience also weighed heavily on discreetness. The startup approached Emerson about making the valve component quieter — a task that had to be done quickly to accommodate Babyation’s tight manufacturing schedule.

The teams collaborated in what Miller described as a “joint engineering” project. They quickly modified the series RB valve so it operated much more quietly, creating an engineered solution that solved one of the biggest problems in conventional breast pump design.

“Emerson has provided fast turnaround support every step of the way. They were always able to very quickly go to the lab, get those prototype parts built to allow us to iterate through our design and find the exact combination of specs,” Miller said. He noted that Emerson also worked with his team to optimize the valve’s placement, keeping noise levels as low as possible.

Babyation’s design, which includes Emerson ASCO’s miniature valve, is small and lightweight, making it easy for on-the-go moms to pump.

The results

“The team at Emerson was instrumental in bringing to bear their resources to look at the construction of the valve that met our flows best, including looking at how they might be able to make a quieter version that fit our specs,” Miller said.

Production of The Pump will continue to scale up, with its official launch scheduled for the near future. Miller says Babyation will continue to partner with Emerson to tweak and optimize the valve for current and future versions of the product.

Most importantly, the product has earned a seal of approval from Rudolph and Miller’s young son Odin, their company’s CBO—Chief Baby Officer.

Emerson | emerson.com/en-us/automation/asco

New hydraulic power units helpmachine tool builder

Southern California Edison assessing the new GHP power unit.

When Advanced Structural Technology (AST) in Oxnard, Calif., approached MJC Engineering (MJC) to replace a spindle-drive on an existing machine, Carl Lorentzen, President of MJC, noticed another issue as well. The outdated hydraulic power unit (HPU) powering the machine — a 30-plus year old conventional 75-kW power pack — was greatly hindering performance as well. Lorentzen recommended a new technology using a variable speed drive equipped HPU by his recently established company, Green Hydraulic Power Inc. (GHP).

AST is a manufacturer of forged and spin/flow formed products for the automotive, defense, aerospace and alternative energy markets utilizing high powered hydraulic machines.

MJC is a custom machine tool builder in Huntington Beach, Calif., specializing in metal-spinning machines for such applications as sheet spinning, flow forming, wheel spinning, and rotary forging. The company’s machines are found worldwide, producing end products such as car wheels, aircraft engine housings, spacecraft fuel tanks, seamless gas cylinders and more. MJC machines typically use a large volume of hydraulic power in operation.

MJC created a turnkey solution that includes system integration, engineering, software technology, and programming under the Green Hydraulic Power (GHP) label. The system incorporates a variable speed drive powering an internal-gear hydraulic pump. GHP claims up to 80% energy savings over conventional hydraulic systems, as well as noise reduction by 20 dBA, less heat generation, lower cooling requirements, less oil volume, and a smaller footprint.

AST expressed an interest in having a new system quoted. GHP proceeded with configuring a new power pack by downsizing the motor from 75 to 45 kW — pumps and motors in conventional hydraulic power units often are oversized to meet maximum duty-cycle demands. By contrast, a variable-frequency drive or servo drive can manage an electric motor’s operating torque and speed more efficiently. Instead of running continuously at full speed, the motor rotates only fast enough to meet system demand at any given time.

AST accepted the proposal and GHP proceeded to build the new HPU.

Soren Rasmussen of GHP had been working with Southern California Edison (SCE) to establish a solution code for this technology — the AST unit was an opportunity to have SCE compare conventional HPUs with VSD equipped HPUs.

SCE installed equipment on the existing conventional HPU, leaving it on for two months to collect as much data as possible, and to better understand the exact duty cycle of the material handling. As soon as SCE completed the energy audit on the existing machine GHP initiated installation of the new HPU.

GHP had been given a three-day window for installation to ensure minimal production downtime, but they were able to complete the installation and implementation in one day, exceeding everyone’s expectations, because they recognize that production downtime is a big concern in manufacturing.

Installing the new GHP power pack.

“When approached by GHP asking us to test a new type of HPU by replacing one of our conventional power packs with a variable speed drive equipped hydraulic power unit to lower energy use, we didn’t think twice about it. The test yielded close to 80% energy savings and a much quieter work environment,” said Rob Melsness, President, AST. “The project resulted in Southern California Edison creating a technology specific Solution Code to incentivize investing in VSD equipped GHP units. We are in the midst of replacing our second unit, and data logging two more HPUs to identify the potential incentives from our local power utility company. We plan on acquiring GHPs for all future HPU replacements as incentive programs are made available by Southern California Edison.”

After a successful installation, SCE was contacted to initiate the energy audit on the new HPU by GHP. Another two months of data collecting passed and the onsite energy audit was complete. Next, SCE compared all the before and after data making sure that each sequence of material handling was identically measured. The result surpassed expectations with energy savings of 78% — an actual summary from SCE reveals savings far beyond what was expected. One significant factor in saving energy for this application is the peak penalty fee — by lowering the peak energy use, paired with a large energy use reduction, the monthly energy saving was $4,288.00 and the ROI for this unit was 11 months. The technology-specific solution code was established, hence incentivizing manufacturers to upgrade their existing conventional hydraulic power systems to variable speed drives equipped hydraulics, typically saving manufacturing process applications up to 80% in energy. This is an essential validation for GHP when a major power utility company provides their customers with incentives to invest in this technology.

Noise reduction was also a significant selling point as well. “As with many of GHP’s previous installations, we get excited about the tremendous energy savings but feedback from most of our clients reflects upon the noise reduction when applying VSD technology,” said Rasmussen.

The GHP line is available in two styles: one with a VFDasynchronous motor and internal gear pump, and the other with a servo inverter, synchronous servo motor, and internal gear pump.

Currently, machines with this green hydraulic unit are in operation at such industry giants as Meritor, SpaceX, Worthington, and multiple plants of GKN Aerospace. All have been in use for more than two years without performance issues. With the widely varying duty cycles involved, Lorentzen concluded, “We can say with high certainty our customers are experiencing up to 80% energy savings, plus the quieter operation and reduced carbon footprint as additional positives. I’m certainly glad I read what others were doing with servo-pump technology, as it’s made a big impact on our company.”

Green Hydraulic Power greenhydraulicpower.com