Latest News Archives - Seal & Gasket Supplies

Tips for Corrective Maintenance in Hydraulics and Pneumatics

engnetwebadmin — Fri, 07 Sep 2018 08:25:36 +0000

“Innovation and product expansion is key, not only for the growth of individual business practice, but to boost growth, employment, productivity and competitiveness in South Africa. We have to align ourselves with the global market in order to gain a competitive advantage” says Seal & Gasket owner Allan Plotz.
In 2012, we purchased the Seal-Master 700, reported at the time to be the largest diameter CNC seal making machine in South Africa. The acquisition has allowed us to expand our product offering to provide comprehensive sealing solutions that can be customised to varying hydraulic and pneumatic applications. “The machine can manufacture seals with diameters from 5mm up to a maximum of 720mm and is able to turn various materials and compounds such as polyurethane, various grades of rubber, plastics and PTFEs” says Plotz. “The machine has immense capabilities and has allowed us expand our product portfolio to better support our original-equipment customers by providing range, quality and reliability that exceed their expectations.”

The industry has seen an increasing need for dependability and longevity in a trade where there is an obvious lack of expertise and skilled professionals. The quality of each individual component is vital in optimising hydraulic and pneumatic capabilities. It is becoming increasingly difficult for companies to absorb the costs incurred from failures or maintenance. “We want customers to understand that compromising on quality components will be more costly for them in the long run. We also need to train operators to identify potential maintenance problems before they transpire, for example, for a seal to operate safely and efficiently, hydraulic equipment needs to operate within a specified maximum speed, temperature and pressure range.” One of Seal & Gasket’s core strengths is our ability to provide technical advice and support before and after the purchase. “Reliability can not only be determined by the product, but also the levels of service and support acquired by your suppliers.”

In order to increase productivity and reduce breakdowns and costly downtime in hydraulic cylinders, Plotz stresses the importance of seal upkeep as a key area of preventative maintenance. “In order to increase the lifespan of equipment and components, industry players need to understand the direct correlation between each part.”

Plotz suggests the following quality control methods to avoid rod seal leaks in order to eliminate the need to replace cylinders and rods:

One of the major causes of seal failure is a damaged piston rod which is caused by misalignment. Poor alignment between the cylinder and the load will cause piston and gland bearings to be exposed to side–loading which will then cause damage to the rod or the surface of the tube, and therefore the seal. This can be an extremely costly exercise because a new piston rod is a customised part that’s made to order and cannot be repaired, but will need to be replaced after a complete strip down and rebuild of the cylinder.

While there is no real solution other than cylinder review and accuracy in machine alignment, it is important to ensure that piston and gland bearings are correctly proportioned to support the cylinder loads and handle the thrust forces created by the application. It is also important to understand that cylinders are designed to provide linear force and that the maximum thrust of this force is limited by its rod diameter and overall length. In cases where Clients have requested a sealing solution to further prevent the issue of misalignment, we have identified and manufactured a profile ideally suited for heavy-duty mobile and stationary service, and that is highly resistant to side loading and insensitive to pressure spikes.
Make sure the seal housing is free from any damage that could possibly harm the seal. It is important to remove all sharp edges and burrs from metal parts, especially ports, grooves and threads over or through which the seal passes during assembly. All seal housing areas, as well as surfaces adjacent to the passage of the seal, must be cleaned to ensure that all metallic bits and other dirt particles have been removed.
To further avoid premature rod seal failure, it is important to lubricate all seals and components with clean operating fluid. Fluid contamination is often the result of water or air suspended in the fluid. Water affects the lubricity of the fluid and causes many seal materials to harden, crumble or disintegrate. In these instances, we offer a hydrolysis resistant polyurethane seal (HPU) as this material is more resilient to high water based fluids at higher temperatures. Heated air bubbles are also a common problem when dealing with hydraulic applications and are commonly caused by a rapid increase in hydraulic pressure. The intensely heated bubbles sit at the lip of the seal and cause small, damaging marks on the inner surface of the seal.
It is important for the seal to be the correct size, type and material. The choice of seal material is extremely important in eliminating problems caused by extreme temperature applications or where the seals may be damaged by chemicals. While a static seal such as a cylinder body O-Ring can tolerate swelling to a degree, the same cannot be said for a dynamic seal which will cause friction and faster wear if swelling occurs. The best solution is to ask your seal supplier for a material recommendation based on a particular fluid.
Seals must be stored (distortion free) in a cool, dry and dark place prior to fitting
Where the difference between a thread diameter over which the seal must pass and the seal diameter is small, use some form of protection over the thread, for example, a fitting sleeve made out of hard plastic
Where seals are fitted to pistons awaiting further fitting, it is important to make sure the seals are not subjected to misaligned or localised loading as this will cause deformation
Remember to flush the hydraulic system carefully before connecting the cylinder to it
Special seal designs should be considered when a severe flow restriction at the head end of the cylinder is accompanied by accidental pressure increases. This, together with an oversized rod, can cause high pressure leakages and rapid wear. We always recommend polyurethane seals as the most effective material to withstand this type of leakage.
We also urge the importance of understanding how the application works and the pressure it requires to better optimise efficiencies. For example, the cylinder may not work to its full capacity because some elastomer lip seals require a minimum pressure level to be fully energised. Your sealing specialist should be able to guide you in terms of what profile is required, based on the amount of pressure to be applied.

Further, it is important to identify that innovation does not only pertain to the product, but also to service efficiencies. “The Seal-Master 700, for which we have a dedicated and trained expert resource, allows for an exceptionally fast turnaround time so we can provide an express service to our hydraulic and pneumatic customers.”

It has also allowed for productivity and accuracy optimisation and developments which, according to Plotz, “are crucial to position South African manufacturers as highly competitive players in the local and global markets.”

The post Tips for Corrective Maintenance in Hydraulics and Pneumatics appeared first on Seal & Gasket Supplies.

Developments in Sealing Technology – DFL108 Polyurethane Static Head Seal

engnetwebadmin — Fri, 07 Sep 2018 08:19:32 +0000

As research and development continues to be at the forefront of product innovation in the sealing industry, it is important that the level of awareness of product development is top of mind amongst seal users. “These days, when production demands are extremely high and pressurized, there is little time for machinery to incur any interruption” says Seal & Gasket Sales Manager, Dulcie Nkambule. “The need to increase the life span and reliability of seals is imperative in order to reduce breakdowns and downtime which can cost companies millions.

As a seal manufacturer, it is our responsibility to ensure our product’s competencies support the operating hours and constraints of our customers.”

This is one of the reasons why Seal & Gasket Supplies has seen an increase in the manufacture and supply of their polyurethane static head seal, profiled as “DFL108” – an expansion of their product range to create maximum efficiency in cost and operations. The polyurethane static head seal is more increasingly being seen as a replacement of the commonly utilized “o/ring and backup” due to common seal failures where extrusion gaps are present on cylinder heads.

Technical Sales Manager, Riaan De Villiers states that “these failures are common in high pressure systems where the gap for the o/ring to seal is too wide and as a result, the o/ring starts to slide between the barrel and the piston. Or the vibration of the differences in pressure variances starts chewing or nibbling away at the o/ring. This can also sometimes be caused because the o/ring material is too soft, hence why we manufacture the DFL108 in polyurethane which provides large performance advantages over traditional elastomers due to its low compression set and strong resistance to extrusion.” De Villiers adds that “an added benefit is that our advanced manufacturing capabilities allow us to customise our products to our customer’s specific requirements.”

When to use the Static Head Seal, DFL 108:

System operating pressure exceeds the limitations of the seal’s extrusion resistance.
Pressure spikes in the system exceed normal operating conditions, risking damage to the seal.
The use of wear rings has increased the extrusion gap, reducing the seal’s pressure rating to an unacceptable level.
The system temperature is high enough to lower the seal’s extrusion resistance to an unacceptable level.
Temperature (-54°C to +93°C)
Pressure 10,000 psi (688 bar) static

With the acquisition of the Seal Master 700, Seal & Gasket are able to custom manufacture standard profiles according to their customer’s specific requirements. “Developments on seal-life prediction and maintenance, as well as advancements in material technology are taking place at a rapid rate which is why a focus on innovation and product expansion is so important.

We have to work to global standards which require more than just traditional products in order to maintain a competitive edge. While innovation encourages growth and strengthens competition, it is most effective together with customer awareness and understanding” says De Villiers.

The post Developments in Sealing Technology – DFL108 Polyurethane Static Head Seal appeared first on Seal & Gasket Supplies.

Benefits of Polyurethane Material

engnetwebadmin — Thu, 06 Sep 2018 14:12:08 +0000

Hydrolysis-resistant polyurethane (HPU) material for seal manufacturing is durable, with excellent wear resistance and good elasticity.

Seal and gasket manufacturer, Seal & Gasket Supplies, now uses large-diameter semi-finished raw materials in nitrile butadiene rubber and hydrolysis-resistant polyurethane (HPU) in the manufacture of its seal products.

“As customers are realising the importance of using high-quality products with higher durability characteristics, materials such as HPU are becoming increasingly popular,” Seal & Gasket Supplies owner Allan Plotz tells Engineering News.

Although rubber is a cheaper alternative in the manufacturing of seals, many contractors are using polyurethane, as it remains sturdy in abrasive environments, which far outweighs cost concerns, he points out.

“HPU is a grade of polyurethane that has a far higher degree of resistance to hydrolysis than standard grades of polyurethane, which tend to show signs of degradation faster when in contact with water, water-based hydraulic fluids and water-contaminated hydraulic fluids.”

Further, Plotz highlights that HPU features include “exceptional durability, with excellent wear resistance, a high level of tear strength and good elasticity”, adding that it is resistant to pure aliphatic hydrocarbons, such as butane, acidic or alkaline compounds, impurities, moisture and alcohols; mineral oils and greases; silicone oils and greases; hot water; ozone, oxidation and ageing; and synthetic esters, which can affect product life.

“These features ensure that the material offers superior service life and, therefore, becomes a far more cost-effective option over the long term,” Plotz stresses. Another benefit is that seals are manufactured with little setup costs and in a much shorter time. Seal & Gasket Supplies produces seals and parts ranging from as small as 4 mm inside diameter to a little more than 700 mm outside diameter in usually less than 24 hours from receipt of order, he says.

Larger diameters of up to 2 500 mm can also be manufactured, but Plotz notes that it generally requires longer lead times. He adds that the demand for seals to be manufactured in HPU has steadily increased, with several customers requesting this material as their first choice.

Further, the company reports that it is also focusing specifically on creating awareness of the benefits of using HPU material in seal manufacturing. While HPU is predominantly used in the manufacturing of hydraulic seals, wipers, bushings and O-rings, Plotz says Seal & Gasket Supplies focuses on using the HPU to manufacture seals in the hydraulic, mining and earth-moving sectors, where water contamination is a common cause of seal failure.

As the material also carries European Food and Drug Administration approval for foodstuffs, it is often used for seals and other components in food and beverage production processes, Plotz says.

Moreover, Plotz emphasises the importance of innovation when designing sealing products to customer requirements, as companies are consistently aiming for ways to enhance their productivity and accuracy.

In light of this, Seal & Gasket Supplies has also decided to acquire the Seal Master 700, a machine that enables the company to customise sealing solutions in a variety of designs and diameters, and manufacture a new range of hydraulic seals to meet the demand for hydraulic cylinders that the industry needs for improved performance.

Industry Needs

Plotz points out that service innovations can significantly boost growth, employment, productivity and competitiveness in the seals and gaskets industry, stressing that more attention should be paid to this area of entrepreneurship.

Further, he stresses the importance and value of enhancing service life cycles through training in aspects such as identifying system leaks.

“We have seen an increasing demand for reliable sealing to reduce leakage,” Plotz says, noting that leakage can occur when incorrect replacement parts are fitted, owing to the perceived lower cost of using cheaper seals and parts. However, the cost of using incorrect parts is higher, owing to damage caused to equipment because of premature failure or incorrect specification, he adds.

In most instances, the quality of a seal is directly associated with the quality of the material, while overall lip design and operating conditions, such as temperature and pressure, as well as correct seal selection, play a vital role in seal performance and reliability, he says.

Other key focus areas includes equipment and seal maintenance, which is becoming increasingly important to reduce breakdowns and downtime, as well as increasing the life span of equipment or components, which requires training and education for the end-users, Plotz asserts.

“End-users and customers must understand the cost implications of using products that are high maintenance and thus the importance of using high-quality sealing products, and products or materials that are durable.

End-users must also understand the application of products on which they use sealing technology to prevent any problems, such as shaft misalignment, which accounts for 50% of all costs associated with breakdowns, Plotz says, citing preventative maintenance as one of the best ways to avoid costly downtime.

“Understanding the potential causes of seal failure can help prevent unplanned maintenance; once predictive maintenance is implemented, companies can reduce and enhance inventory levels of spare components,” he concludes.

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