• lens seals, which provide peripheral sealing;
• trunnion seals, which seal the valve shaft.
  In some cases, a connecting seal is also used between the valve body and the pipe.

Let's take a look at the constraints of butterfly valves in terms of sealing and the different types of seals available.

1. Specific features/constraints of butterfly valve seals

Comprehensive support, from design to operation

1. Design and expertise: analysis of the existing solution on site and in the design office.
2. Technical recommendations: delivery of a technical file including analysis of existing equipment and recommendations, 2D and 3D drawings, and drawings of parts to be re-machined with dimensions and machining tolerances.
3. Manufacture of the sealing system: manufacture of molds (if necessary) or production of seals using existing tools.
4. Assembly assistance: participation in dry assembly at the customer's workshop, adjustment and inspection of the seal to ensure uniform contact around the entire circumference of the valve body and a perfect seal.

Butterfly valve with centered trunnions and bezel seal (monobloc between the lens and trunnion parts)

2. Types of valves

There are two scenarios: centered or off-center lenses. The sealing structure differs considerably between these two scenarios.

Butterfly valve with centered lens / Butterfly valve with offset lens

a. Off-center lens cases

In the case of butterfly valves with off-center pins, the lens seal is not affected by the presence of the pins and can therefore be monobloc. PXL SEALS designs and manufactures monobloc lens seals, molded without joints in its production workshops in Valserhône.
This technology guarantees optimal and consistent sealing, even on very large diameters.
Key benefits:

• Fully molded seal, without gluing or joints
• No size limitations (we have produced seals with diameters of over 7 m for this type of equipment)

b.Centered lenses

In the case of a butterfly valve with centered pins, we offer a high-quality molded seal delivered in length.
In this case, given the complexity of the connection between the lens seal and the pin seal, it will be necessary to make adjustments and modifications directly on the valve once the seals have been installed. Given the precision required for these operations, we recommend that you call on experienced technicians or our teams to carry them out.

3. Lens seals for butterfly valves

- Standard lens seals

Joint de lentille standard PXL SEAL


Simulation extract of a lens seal

- Other lens seals used
The profile shown in the previous section, although the most common, is of course not the only lens seal available. Depending on the original design of the valves, or in order to address specific operating issues, there are a multitude of seal profiles available, which is why we have a wide range of tools at our disposal.
From moulding to packaging, each stage is carried out under strict control:

• Quality control at each stage of production,
• Customised packaging to preserve the integrity of the seal until delivery
• Comprehensive technical support.
  

4. Butterfly valve spindle seals

For spindle seals, PXL SEALS offers a wide range of solutions adapted to the operating conditions and specific design of each valve. The seal usually consists of a combination of several seals: static seals between the bronze bushings and the valve body, dynamic seals between the bronze bushings and the pins, but also and above all seals between the bronze bushings and the lens seal, which are also considered dynamic.
While static seals are mainly composed of O-rings or D-profiles, dynamic seals can be made with a number of different solutions depending on the valve design: U-seals, chevrons, composite seals, elastomer rings, flat strips, washers.
In terms of materials, again, a wide variety is possible depending on the type of seal and the conditions of use:

• U-shaped seals: NBR, HNBR, PU, etc.
• Composite seals: combinations of high-performance materials such as polyurethane (PU), PTFE or polyethylene (PE) with NBR and HNBR.
• Chevron seals: made of textile NBR or polyurethane.

5. JB182 flange gaskets

Butterfly valve flange gaskets are installed between the valve body and the pipe. While these seals are sometimes provided by simple O-rings, in some cases they are provided by the JB182 gasket profile specifically developed by PXL SEALS.
This profile was developed to replace the old seals made from matted lead.
This profile consists of two separate parts, making it easy to install while ensuring the essential functions of this seal:

• Rigidity is ensured by the inner part
• The outer elastomer envelope ensures sealing and also gives the system flexibility and deformation capacity

Deployed at several sites, this new profile has proven its reliability and significantly facilitates installation, while eliminating the use of lead, which is no longer usable today for this type of function.

Check out the article JB182 profile for butterfly valve flange sealing

For any design, replacement, or maintenance requests, you can contact us at any time.
To learn more, discover some of our projects:

• Replacement of the butterfly valve sealing system
• Repair of a butterfly valve sealing at Génissiat

These gates play an essential role in the safety, operation, and performance of hydroelectric structures. Their seals are subject to mechanical, hydraulic, and environmental stresses and must meet high standards of reliability and durability.

PXL SEALS has many years of experience supporting operators and maintenance teams by offering innovative, tailored sealing solutions. One such solution is our EPDM HydroRubber compound, a robust, environmentally friendly material specially developed for valve seals that complies with DIN 19704, the industry benchmark standard.

1. Meeting the constraints of structured gates

PXL SEALS has been providing comprehensive solutions for various types of structured gates, including segment gates, lift gates, roof gates, wagon gates, cofferdams, and flap gates, for many years.

What are the challenges of valve seals?

Often considered "negligible" because they are obtained by extrusion, these seals are actually a major challenge.

• Depending on the type of valve, they are not always easy to replace. They are exposed to the elements and the presence of abrasive solids (sediment, dead wood, stones, etc.), so they can easily become damaged.
  Optimizing mechanical properties is therefore a major challenge for users.
• Connection areas (bonded joints) are also critical areas, as they can lead to leaks, torn seals, etc.
  For all these reasons, we present here the solutions and products offered by PXL SEALS to best meet your expectations.

2. Profiles Designed for framed valve Seals

To meet user requirements, PXL SEALS offers a dedicated range of structural valve seals.

We have a wide selection of profile dies, ranging from standard shapes like music notes, flat strips, and angle irons to highly specific profiles. We also develop profiles tailored to our customers' needs. We can supply any profile type according to your needs.

Musical notes (hollow, solid) - Angle bars, flat strips - Special profiles

Browse our selection of profiles. These profiles are obtained by extrusion, and the manufacturing tolerances are in accordance with ISO 3302-1-E2. A table of values is available upon request.

Toolings for framed gates seal manufacturing

3. EPDM HydroRubber Compound

We can offer a wide range of materials to meet your specific requirements. However, due to the primary constraints of these seals, we primarily offer our EPDM HydroRubber compound. This compound has been specially developed and tested for these applications.
The compound has been tested in a laboratory to validate its compatibility with DIN 19704, the reference standard in waterproofing for steel valves.
A summary of the values obtained for our compound is provided below.

Advantages of PXL HydroRubber:

• Meets the specifications of the main players in the hydroelectricity sector (DIN 19704)
• Offers exceptional durability in water and outdoors (good ozone resistance).
• It has a limited environmental impact and respects the aquatic environment. Unlike polychloroprene compounds used in the past, it has no toxic emissions and does not have a significant environmental impact.
• It has excellent resistance to breakage and tearing.

4. Corners, Frames, and Connection Methods

In addition to supplying profiles in various lengths, PXL SEALS offers finished or semi-finished corner blocks and frames.

• Molding corner blocks: Using molded corner blocks, when possible, avoids the need for cold bonding at 45° in corners. These areas tend to be subject to stress, with a high risk of bond failure.
  Furthermore, these joints are not always easy to make, especially for slightly unusual profiles, right angles, and single-note angles connected to double-note angles.
  These blocks can be delivered with extruded products to allow you to create joints on-site in straight areas. This method is much easier and more reliable.
  We currently have a wide range of blocks in stock and can produce new ones to meet your specific needs.

A few examples of molding corner blocks

• We offer half and complete frames as genuine turnkey solutions that facilitate assembly, reduce the number of joints that need to be made on site (often in difficult conditions), and ensure the joints are more reliable.
  We can supply different types of frames according to your needs, the type of profiles, and the valve. We recommend supplying half-frames with extra length that can be adjusted on site. This allows you to adapt exactly to the actual valve, which may differ from the plans.
• Most PXL joints are made using cold or hot bonding (HLB) depending on the circumstances (joint area, tools, profile type, frame design, etc.).

When manufacturing our frames, we use a hot bonding process with material addition (HLB).
In certain cases, PXL SEALS uses the HLB ("Hot Layer Bound") process, which was developed by our design office. This process does not require glue and provides superior results compared to cyanoacrylate bonding.
You can join directly at a 45° angle instead of using cold bonding. The extruded profiles are joined using a mold. Alternatively, the joints are made between molded angles and extruded profile lengths.
Depending on the type of profiles and the shape of the frame, one method or the other is used.
The frames are made from PROSEAL profile extrusions.

PXL SEALS has a large inventory of standard items and can also design profiles with specific dimensions.

4 - Expertise and replacement of complete frames on the customer's site.

In addition to supplying finished or semi-finished profiles and frames, PXL SEALS can work on-site to adapt seals to equipment and carry out bonding. In this case, we can only carry out cold bonding.

• Expertise and adaptation of solutions based on the technology and initial design of the valve.
  When replacing a structural valve seal, adaptation to the terrain, technology, and initial design of the valve is necessary. To determine the best solution, it is sometimes useful to visit the site and check for potential areas of weakness and risk of leakage.
• Installation and adjustment of valve frame seals
  PXL SEALS teams can assist with installing your valve frames on site when necessary. We can also cut to length, glue, and drill holes. See the possibilities, depending on the type of installation and our availability.
• Adjusting or shaping parts.
  Sometimes, it is necessary to "shape" parts to adapt them to the structure because this cannot be done directly on the manufactured part. Extra thickness can then be applied to the part in question to allow for these adjustments.

By choosing PXL SEALS and its HydroRubber range, operators are guaranteed a proven, environmentally friendly, sustainable solution that can withstand the most severe constraints of framed valves.
With expertise in design, manufacturing, and on-site interventions, PXL SEALS offers more than just seals—it offers a comprehensive, reliable, turnkey solution that guarantees performance and durability.
Opting for PXL SEALS' valve sealing solutions means choosing safety, reliability, and time savings thanks to simplified installation and reduced risk of leakage.

Contact us for more information on framed valve seals.

In the field of hydroelectricity, Kaplan turbine operators understand the importance of blade sealing. Failure of these components can result in an immediate halt to electricity production, causing economic losses that can amount to hundreds of thousands of euros.
With over 30 years' experience, PXL SEALS has developed a specially designed sealing solution for the blades of vertical and horizontal Kaplan (bulb) turbines, making operations safer and significantly extending turbine life.
How can the PXL SEALS sealing solution extend the life of your Kaplan turbines?
The answer lies in a fully tried-and-tested, comprehensive solution combining a set of seals and compensation rings that enable the optimal positioning of the seal within the housing, a unique MD WAY® on-site moulding process and the expertise of our service teams.

1. A seal profile specifically designed for hydroelectric turbine blades

The PXL SEALS solution is based on a one-piece, fully-molded seal: the U150-XI DE profile.
This joint is the result of decades of research and feedback from the field on Kaplan turbines. It takes into account not only the problems of the application itself, but also those of previous solutions, such as chevrons and back-to-back U-joints.
This tried-and-tested solution has been optimised regularly for over 20 years to address all the new problems encountered in the field. Its main advantages are :

• Easy-to-install single seal
• Good positioning in the housing
• Preservation of housing condition over time
• Can be molded on site using PXL SEALS’ MD Way system

This one-piece joint is moulded as a single unit with no joints, offering perfect dimensional consistency across its entire diameter.
This design guarantees stability in the housing, easy assembly, and a double-acting seal (oil/water and water/oil), which is essential for the safety and efficiency of installations.
Designed for both original equipment (OEM) and maintenance (MRO), the sealing system can be installed in most cases without reworking the housings.

2. The seal - ring combination to preserve the housing

The solution developed by PXL SEALS is not limited to the seal itself, but encompasses the entire sealing system, including seals and compensation rings. The rings are placed between the housing and the seal, enabling the seal to be positioned in the healthiest area of the housing to achieve the best possible sealing.
In new installations, the seal assembly with compensation rings preserves part of the housing: the seal is positioned on the water side and the oil side includes the compensation rings. During maintenance, the seal can be shifted to the oil side by moving the compensation rings. This means that the seal lips can continue to be applied to healthy surfaces that were previously maintained in oil.
The result is major time and cost savings, since the seal only needs to be positioned in a small part of the housing. This enables successive maintenance operations to be carried out without the surfaces (hub and blade) needing to be reworked.

3. The exclusive MD WAY® on-site molding process and the HLB hot-joint

Another decisive advantage is the patented MD WAY® process, developed and used exclusively by PXL SEALS. This technology enables molded joints to be made directly on site, without dismantling the equipment.

• A factory-like quality joint
  With mechanical and chemical resistance superior to conventional hot or cold finger-jointing methods.
• Easy to install!
  The MD WAY® process can be adapted to suit any site configuration, even in cases where access is difficult or there are severe constraints.
• Comprehensive expertise and a team that makes all the difference
  Every project includes a metrological assessment of the housing (eccentricity, surface conditions, tolerances), custom design of the sealing system, and preparation and installation of the elements. This expertise guarantees the long-term reliability of the solution.

However, the MD-WAY process is subject to a number of dimensional constraints. For blade trunnion dimensions that are too small, the alternative is our HLB hot-joining process. Although this process has slightly inferior characteristics to MD-WAY, it is still far superior to cold bonding.

4. Examples and feedback:

The PXL SEALS solution has already been adopted by numerous hydropower locations. Here are just a few examples:

- Sealing of Kaplan turbine blade bearing trunnions without dismantling

In order to ensure optimum production continuity while minimising plant downtime, PXL SEALS has replaced the traditional sealing method for Kaplan turbine blade trunnions at several hydropower plants, using the exclusive MD WAY® on-site moulding process.
On-site interventions included all or part of the following services:

• Design and installation of the sealing system;
• Metrological inspection of housings (e.g. eccentricity);
• Inspection of surface finish;
• Preparation of housings;
• Moulding and seal assembly.
• Delivery of a complete work report.

These activities were carried out on Kaplan turbines in France and abroad.

- Replacing blade trunnion seals on bulb turbines at the La Rance tidal power plant.

• Design and manufacture of the sealing system;
• Supply of scaffolding;
• Removal and reinstallation of seals;
• Implementation of turbine rotations;
• Metrological inspection of housings (e.g. eccentricity);
• Inspection of surface condition, including quantification of journal wear;
• Preparation of housings;
• On site moulding using the MD WAY® process and fitting of seals;
• Requalification implementation;
• Delivery of a complete intervention report.

- Replacement of blade trunnion seals with on-site reworking of the housings.

PXL SEALS took up the challenge of a complex intervention on a bulb turbine in operation: severe wear to the hub and trunnions, and significant variations in the cross-section of the housings (subsidence). Dismantling the turbine was not feasible given the scale of the project.
In response to these constraints, PXL SEALS developed a specific technique for reworking the housings and eccentricities on site without machining.
This innovative solution enabled us to use our U150-XI DE seal, which is joined via the MD WAY® process. This would not have been possible without the housing recovery.

Solution deployed:

• Assessment of the dimensions and quality of the units;
• Design of the wear and eccentricity recovery system;
• Installation of surface and eccentricity recovery systems;
• Re-appraisal after installation;
• Design and manufacture of seals;
• MD WAY® on-site moulding and assembly of seals and rings;
• Delivery of a full service report;
  The oil was requalified and the turbine was refilled as normal, ensuring continuity of operation.

The Kaplan blade seal solution from PXL SEALS offers a comprehensive and long-lasting response to the demands of the hydroelectric industry.
Thanks to its high-performance, one-piece design, adjustable compensation rings and exclusive MD WAY® process, it helps secure installations, minimise equipment downtime and prolong the lifespan of all machinery, regardless of operating conditions.

See also the full range of seals for hydropower
More information on on-site jointing processes

1) Seals for large bearings and slewing rings: 30 years of expertise

For over 30 years, PXL SEALS has been designing, manufacturing and supplying customized and standard sealing solutions for large bearings and slewing rings.
Our expertise is used in a wide range of sectors including energy (wind power, offshore), shipbuilding (PODs), industry (bottling lines....), construction, civil engineering and other activities requiring specific seals for bearings.
The command of the value chain, from solution design to on-site delivery, makes PXL SEALS a preferred partner of manufacturers and end-users of large bearings and slewing rings which are strategic components.

Sealing design in the design office

All the seals for large bearings and slewing rings designed by PXL SEALS are developed by our design office.
To do this, our engineers and design office technicians carry out studies and technical files, which can be based on on-site expertise.
They use advanced tools such as :

• Finite element analysis (FEA): analysis of seals’ behavior under stress.
• Laboratory tests: experiments on test benches, etc.

For these high-value applications, PXL Seals favours fully moulded solutions with tight tolerances.
When requirements are common to several applications, sealing solutions are integrated into PXL SEALS’ standard product range.

Manufacturing of large and very large diameter seals

Some equipment, such as tunnel boring machines or wind turbines in civil engineering, require very large-diameter seals that can be more than ten meters in diameter.
In its manufacturing facility, PXL SEALS is equipped with the machines and presses needed to produce these seals, guaranteeing total quality control.
Our products are then carefully packaged and shipped to site, with the option of installation by our PXL On-Site team.

2) Seals that meet the requirements of large bearing manufacturers

Large bearings and slewing rings are subject to extreme conditions:

• Continuous vibration: affecting part alignment
• Variations in temperature and humidity: affecting the ageing of seals.
• Abrasive environments: exposure to dust and mineral residues.
• Significant eccentricity: due to oscillating or slow rotating movements.

Our one-piece, fully moulded seals offer optimum sealing, preventing the intrusion of foreign bodies, while maintaining component lubrication.
These high-precision seals can be manufactured in a wide range of elastomer grades and sizes. They can be installed and joined on site using our MD WAY moulding process, which guarantees the same quality as mouldings made in our workshop.
The durability of the materials used is crucial to minimize maintenance operations on sites that are often difficult to access.

3) Case studies 

Discover some of our experiences on applications using large bearings and slewing rings, from design, manufacture to maintenance.

Naval sector: sealing of thrusters (PODS)

Seals on thrusters (PODS), propeller shafts and boat engines are particularly strategic, as replacing them is generally costly in terms of equipment downtime and the resources required to carry out the replacement (taking the vessel out of the water): they must therefore be extremely reliable.
Different options are available, depending on the type of seal and the needs of the equipment:

• Perobat-type rotary lip seals can be supplied ‘split’, enabling on site installation by cold gluing, without dismantling the equipment
• Full-elastomer seals can be supplied open for on-site moulding using the MD-WAY process, hot or cold joining.
• All these seals can also be supplied single-piece, without junctions, for original equipment.

Read the full article

Replacement of a propeller seal (PODS)

Our teams had the opportunity to replace POD seals in Las Palmas (Spain) following a leakage.
PXL SEALS replaced this strategic POD seal on a cruise ship with a fully moulded seal joined on site using the MD WAY process.
This kept dismantling to a minimum, enabling the work to be carried out in a short space of time and minimizing the vessel's downtime.

Monaco breakwater: maintenance of mechanical ball joints

Since 2000, PXL SEALS has been carrying out the 10-year maintenance on the seals of a mechanical connection linking a floating barge to the coast.
The seal, 2.30 m in diameter, is located 8 m below sea level.
In 2016, following a study, we replaced the ball joint seal without dismantling it, using the PXL SEALS’ MD WAY on-site moulding process, guaranteeing maximum protection against water intrusion.

Read the success story

Brighton: British Airways i360 seal replacement

After designing the seal, our team carried out a seal replacement of the observation tower's bearings of pulley, without disassembling the equipment, in a cramped environment.
Read the success story

4) Examples of seal types by sector

The following seals can be designed and manufactured by PXL SEALS:

Wind energy seals

Common seals include blade seals, rotor bearing seals, gear shaft seals, alternator seals and nacelle ring seals.

Seals for the offshore / oil and gas sector

Oil platform swivel seals are bearing seals that we supply to players in the offshore oil extraction sector.

Sealing for the naval and maritime sectors

In the naval sector, we design POD seals (rotating ring seals, slewing ring seals), propeller seals (nacelle bearing seals, blade seals and propeller shaft seals), radar seals such as tilt reducer seals and slewing ring seals.

Seals for public works and forestry machinery

Various types of seals are produced for the public works and forestry machinery sectors, such as crane seals (muffle gear seals, slewing gear seals, nacelle crown seals and carriage gear seals) and seals for mechanical machinery, mainly slewing bearing seals.

Construction and civil engineering equipment

Various types of seals, generally with large diameters, are used on construction equipment, such as seals for tunnel boring machines (TBMs), mainly to seal the bearing at the head of the TBM.

Industry in general: Seals for industry

PXL SEALS applies its expertise to equipment using large bearings and slewing rings.
From design to maintenance, our sealing solutions guarantee performance and reliability in complex environments.
We support our customers in their technical challenges with total control of manufacturing, our design office and unique on-site expertise to ensure the longevity of their equipment.

1.The constraints of seals for TBM and construction

These applications involve stringent demands on sealing systems because the slewing rings and large bearings present in equipment such as TBM (Tunnel Boring Machines), cranes and turrets undergo:

• Continuous vibrations which can affect the alignment of the parts,
• Substantial temperature and humidity variations,
• Abrasive environments such as dust and mineral residues,
• Substantial eccentricity which results from oscillating movements or slow rotation.

These conditions require seals that can maintain lubrication while preventing the infiltration of foreign bodies.

Moreover, the durability of the materials is crucial in order to minimize the maintenance work at sites that are often difficult to access.

2. The PXL Jumbo seal, a rapidly available, customized solution

The PEROBAT Jumbo seal was developed for applications that require low pressure seals combined with slow rotating movements, constraints which are specific to large bearings.

Its characteristics make it an ideal solution for the demanding environments of tunnelling, the mining industry and public works:

• Adapted to slow or oscillating rotating movements, the Jumbo seal can be adapted to variations of section and the eccentricity of parts, without compromising on the sealing,
• Designed with high-performance materials selected for specific conditions (temperature, contact with fluids, low pressure),
• Exceptional durability: entirely molded seals with narrow tolerances compared with other means of processing to ensure maximum compatibility.

Seals available within very short time frames

The systems available in our production facilities allow us to handle a wide range of requests and to make entirely molded parts, with diameters of up to several meters. Our manufacturing times range from several weeks for standard orders to very short deadlines of 1 to 3 weeks.

Here are some examples of standard sections:

* Diameters in mm

More info about large bearing seals

Download the JUMBO seal technical information sheet

Other dimensions are available, please contact us for further information.

3. Use of the Jumbo seal: different type of assemblies/configurations

The PXL Jumbo seal can be used in different assemblies as a function of the exterior environment and the level of safety required.

Here are some examples of assemblies of Jumbo profiles. The PXL SEALS team is at your service for advice and technical studies for your equipment.

• Mounting of a single seal

• Mounting of two seals in tandem

• Sealing in two opposing directions

Design, on-site services and work

Beyond the manufacturing of Jumbo seals, PXL SEALS accompanies its clients each step of the way in order to ensure optimal sealing:

• Technical on site expertise: our teams can come to you to evaluate the specific constraints and to offer adapted solutions. 
• Design and technical studies: with its 30 years of experience and its design department, PXL SEALS can also design customized sealing solutions. 
• Installation and maintenance: the seals can be molded or replaced directly on site, throughout the world, thanks to our on-site molding and bonding techniques.

PXL SEALS offers an innovative technique, the MD Way method, which involves molding seals directly on-site without needing to dismantle the equipment. This approach reduces downtime and optimizes costs.

Jumbo seals are a good example of PXL SEALS’s expertise and know-how in addressing the specific constraints of large bearings.

Their performance, combined with the customized services which we offer, make them the obvious choice to ensure the reliability and durability of equipment for the tunnelling and construction industry.

Contact us for further information.

Our HLB (Hot Layer Bonding) process is used to replace seals on all types of application, whatever your line of business.

The HLB process offers an effective quick repair solution to stop leaks without having to completely dismantle the equipment. By avoiding the need to dismantle the mechanical parts surrounding the seals, you save both time and maintenance costs.

Increasingly popular with our customers, the HLB process stands out for its simplicity and efficiency. But how exactly does it work? And what are its advantages over other available jointing techniques?

1. What does the HLB on-site jointing process involve?

Through the HLB process, the joints - manufactured in the workshop by PXL SEALS - can be jointed end-to-end directly on site using some added material.

The two ends of the component are placed against each other by inserting a non-vulcanised pellet of elastomer of identical quality to the already vulcanised product.

This process avoids the presence of hard spots (no additives other than the elastomer) and the mechanical properties are significantly improved in comparison with cold bonding.

The HLB portable press is a tool specially designed by PXL SEALS for use in the field.

2. For which applications?

With the HLB process a large number of seal profiles can be hot-jointed: extruded seals supplied to length (O-rings, quad-rings, U seals, V-rings, etc.) or even profiles moulded and closed to a diameter that cannot be installed as a single piece because of mechanical constraints and limited available space where the mechanism cannot be dismantled.

• Conditions for using the jointing process on an HLB site

The only constraint on the use of this process is the diameter of the seal, which must be large enough for it to be jointed. The process can generally be applied on seals with a diameter of 300 mm upwards with possible adjustments depending on the specifics of the project, such as the cross-section of the joint and the space available around the bonding area.

The HLB process can be used on all applications using elastomer seals (NBR, HNBR, EPDM, CR, etc.). The flexibility of the process means that seals with different diameters can be jointed end-to-end using the HLB press, subject to prior technical validation.

This ability to adapt to the specific needs of each installation makes the HLB process particularly versatile.

3. What are the advantages of HLB jointing?

• Increased resistance:

The HLB process stands out for its robustness. Unlike cold bonding, which uses glue that can degrade over time or under the effect of fluids, the HLB process relies solely on the elastomer, ensuring greater tensile strength and eliminating the risk of breakage.

• Durable:

Another major advantage of the HLB process is its durability. The elastomer used to create the joint is identical to that used for the seal, ensuring perfect compatibility with the fluids in contact with it.

This considerably reduces the risk of deterioration of the joints over time, offering a reliable and durable solution for your installations.

• Responsive and practical:

The HLB process also enables optimised stock management. Seals can be stored either closed to a diameter or in lengths, then jointed on location as required.

This flexibility makes it possible to respond quickly to unforeseen circumstances and maintenance requests without operations being delayed.

4. Training and installation of joints by your own teams

The HLB process does not necessarily require the direct involvement of PXL SEALS teams. We have designed the process so that it can also be used by your own teams after appropriate training.

• Training:

Training in the use of the HLB press is easy and accessible, even for operators with no previous experience in this field.

Our qualified trainers will help you to master every stage of the process, from preparing the seal to making the joint.

• Operational independence:

Once trained, your teams can make the joints themselves on site, without always having to call in our technicians.

This independence means that you can reduce response times, reduce the travel costs of our teams and respond immediately to maintenance needs. This is particularly advantageous for critical installations or in environments where downtime must be kept to a minimum.

• Technical assistance:

PXL SEALS is available to provide ongoing technical support if necessary. Whether for application-specific advice or one-off tasks, we make sure your team has all the support it needs to make the most of HLB technology.

5. Comparison with other on-site jointing processes

PXL SEALS offers several on-site jointing processes to meet the specific needs of each project:

• MD Way®: With this on-site moulding process, strategic or vital joints can be produced directly on site. This is ideal for configurations requiring maximum precision.
  However, it is more expensive and complex to carry out than the HLB process.
   
• Cold bonding: Cold bonding is a simpler but less resistant method, suitable for applications where mechanical stresses are lower (static assemblies) and where the installation can be easily dismantled and replaced.
  However, this process involves an increased risk of deterioration over time, particularly due to the use of glue.

The HLB process has the following advantages over these other methods:

• No hard spot: Unlike cold bonding, HLB jointing does not introduce any hard spots into the seal, ensuring optimum flexibility and elasticity.
• Savings: HLB is less expensive than the MD Way® on-site moulding process and offers an excellent compromise between cost and performance.
• Versatility: The HLB process makes it possible to join smaller diameters end to end than with MD Way, offering greater flexibility for various types of projects.
• Easy to carry out: The HLB process is easier to use than MD Way and your teams will be able to make the joints after a quick training session.

Find out more about the various on-site jointing processes offered by PXL SEALS.

To sum up, the HLB on-site jointing process provides an efficient, flexible and cost-effective solution for on-site maintenance operations, while maximising responsiveness and increasing the durability of the joints.

Whether you opt for the involvement of our experts or team training, PXL SEALS is committed to providing you with the tools and skills you need to optimise your on-site jointing processes.

Contact us for more information

Guide vanes are devices present at hydroelectric facilities, in the zone called the distributor which allows for regulation of the water flow arriving at the turbine by opening or closing. This regulation is more or less broad and operational according to the design of the machine.

Are turbine trunnion blade seals used in this place? What types of seals are used? What are the particular features of these seals? What sealing solutions can we offer?

1 - What types of seals should be used for turbine Guide vanes?

There are several sealing zones linked to these guide vanes. The most common ones and the ones that we work on very regularly are the guide vane seals. These are seals located at the level of the trunnion blades and which are intended to prevent water from entering the guidance area.

The company works in various sectors including hydroelectricity, wind energy, tidal power, oil and gas/offshore, naval equipment, public works and forestry equipment, defense, and various sectors of industry in which sealing is extremely important.

How does PXL SEALS meet the needs of manufacturers of large bearings, from their manufacturing up to on-site installation and maintenance?

Seals that comply with multiple constraints

The seals of large bearings and slewing rings have unique features. These strategic components must meet significant constraints, particularly:

• Very large diameter seals (greater than 3 meters)
• Vibrations
• Strength over time / durability
• Eccentricity / clearance of parts
• Orientation or continuous movement depending on the situation

The particular operating conditions of certain types of equipment, such as the presence of fluid in contact, speed, service life and temperature, may make it necessary to use specific materials.

PXL SEALS has the necessary know-how in elastomer chemistry to offer solutions adapted to its customers’ needs.

- The importance of materials

The choice of the materials for seals for large bearings and slewing rings is crucial to guarantee optimal performance. PXL SEALS offers a range of materials adapted to the various operating conditions, ranging from standard elastomers to specific materials developed in-house or with specialized partners.
This approach ensures maximal compatibility with the requirements of each application.

The manufacturing of seals for large bearings

1) The range of seals offered by PXL SEALS

In order to meet its customers’ specific needs, PXL SEALS offers a diversified range of entirely molded unitized seals, of large and very large diameters and high precision.

These dynamic seals for rotating or oscillating movement are available in various sizes and of several grades of elastomers.

- V-Ring seals

The family of V-Ring seals is broad, with many profiles. These seals are used to provide protection against dust and fluid splashing or to retain grease, without pressure:

- Function in contact with continuously rotating tracks.
- Offer a wide range of possible diameters.
- Can be made of various grades of materials depending on the operating conditions.

- PEROBAT seals

Another major product line is PEROBAT seals. These rotary shaft seals are designed to function on tracks in continuous rotating movement:
- Cover a very wide range of diameters.
- Made from different materials to adapt to specific requirements.
- Available in several versions, including single lip, reinforced double lip, and a JUMBO version for slewing rings or large bearings.

PEROBAT JUMBO seals

PEROBAT JUMBO seals for slewing rings or large bearings are designed to function on tracks in slow rotating or oscillating movement and must allow for recovery from eccentricity or section variations, often substantial, linked to the movement of parts with respect to each other.

These seals are designed to function at low pressure, or even in the absence of pressure.

Discover the PXL seal product lines for large bearings

2) Custom-made seals

PXL SEALS has a design department which capitalizes on more than 30 years of technical experience to meet the specific sealing needs of its customers.

This design department uses calculation and control methods such as the finite element method, often accompanied by tests on a test rig, to design customized solutions which are perfectly adapted to the requirements of each application.

In high-stakes applications, PXL SEALS favors entirely molded solutions, with tolerances which are narrowed with respect to other means of transformation. This approach ensures maximum compatibility with the specific constraints of large bearings and slewing rings, thereby guaranteeing optimal performance and increased durability.

On-site work

PXL SEALS offers a complete on-site service to support its customers during the assembly or repair of seals for large bearings and slewing rings.

Our various methods of on-site bonding provide turnkey solutions with no dismantling of equipment, whether for simple assembly, bonding or molding.

Discover some examples of seals for large bearings and slewing rings manufactured and installed or replaced at our customers’ premises

Maintenance of existing seals:

• Replacement of boat propeller seals (PODs): Maintenance work to replace the seals that equip a boat POD after damage. On-site molding to guarantee optimal sealing.
• Sealing of the ball joint for the Monaco seawall: Design, delivery and replacement of the seal in situ. On-site molding to ensure maximum protection against water seepage.

The manufacturing quality of the seals is guaranteed by the MD WAY on-site vulcanizing process®, guaranteeing standards of quality and finishing identical to those obtained during the initial molding.

Delivery and installation of new seals:

• Delivery of entirely molded seals to protect the bearings of a bottling plant.
• Manufacturing of entirely molded seals for the bearings of forestry machinery, equipment for construction and public works or tanks.
• Work on wind generator nacelles: Delivery of seals for the main bearing of large wind turbines and for slewing rings for wind turbines.
• Tunnel boring machine crown maintenance: Delivery of seals for tunnel boring heads and their main bearing, thereby guaranteeing reliable sealing in extreme conditions.

Our qualified teams work with responsiveness and professionalism in order to ensure the efficient implementation of on-site sealing solutions, while minimizing the downtime and ensuring the sustainability of the facilities.

Contact us for further information about seals for large bearings.

Download the Large bearings and slewing rings flyer

PXL SEALS was among the first to implement non-stick technologies that makes it easy to replace a joint without dismantling the equipment. This reduces maintenance times, resulting in considerable savings.

The on-site team uses two processes to carry out this maintenance: the patented MD Way™ on-site moulding process and the HLB (Hot Layer Bonding) on-site jointing process.

Our customers increasingly ask for on-site jointing using the HLB process.

What is the principle behind HLB on-site bonding? What are the advantages of HLB over other jointing methods?

1. What does the HLB on-site jointing process involve?

Using the HLB process, a new seal manufactured by PXL SEALS can be fitted directly on site, with added material.

The two ends of the component are butt-jointed by adding a pellet of non-vulcanised material. By adding a layer of material close to the jointing material, the appearance and properties of the joint area obtained becomes homogeneous.

2. What are the advantages of the HLB joint?

By adding a raw elastomer, which is vulcanised directly on site, the elastic properties of the elastomer, and therefore of the joint, are maintained and there are no hard points.

The joint can be made with a portable press by the PXL SEALS team or by your teams after purchasing a portable press and being trained in its use. HLB technology is easy to use and requires no particular experience or qualifications.

All diameters of 300 mm or more can be butt-jointed with an HLB portable press. Subject to validation, the diameter can be smaller depending on the profile and the available space.

All manufactured joints, closed to a given diameter or stored in lengths, can technically be butt-jointed using the HLB process.

When is the HLB process particularly suitable?

The HLB on-site jointing process is particularly suited to equipment where there is little space to make the joint.

3. Comparison with other on-site jointing processes

To meet the needs of our customers and the particular features of each rehabilitation project, PXL SEALS recommends different types of on-site jointing processes, depending on the project: MD Way®, HLB and jointing by cold bonding.

You can find out more about the characteristics of these on-site jointing processes on this page.

The advantages of the HLB process over other bonding solutions offered by PXL SEALS are as follows:

• There is no hard spot at the joint, unlike with cold bonding;
• It is a more economical solution than the MD Way process, which is true on-site moulding;
• Even the smallest diameters can be jointed ;

• The HLB process is easier to implement than MD Way. The joints can be made by your teams after training in the use of the portable press.

4. Examples of projects

Take a look at some examples of work carried out by PXL SEALS on our customers' sites.

Work on a paddle seal

Housing seal for the intermediate bearing of a reversible Francis turbine

The HLB on-site bonding process is a high-quality, cost-effective solution for many maintenance projects that do not justify the use of a fully moulded joint without bonding.

It is an interesting alternative to on-site bonding of the elastomer joint without dismantling turbines or equipment in the hydroelectric, energy, naval and industrial sectors.

The PXL SEALS team can help you choose the process best suited to your requirements.

With the on-site moulding and bonding solutions provided by PXL SEALS, you can save time and the cost of dismantling your installations!