Stepanovich Blog

O rings are acceptable for static sealing but inappropriate for dynamic sealing applications such as pumps and compressors, and high and low pressure applications.

In cases where dynamic sealing applications are required such as pumps and compressors, and high and low pressure applications, a single elastomer may be used with an X-ring profile to prevent twisting in rotary applications. However a composite seal design is often preferred.

A composite seal is a combination of two or more materials to produce a seal that offers the best attributes of both materials. For example, a T-shaped seal comprises an elastomer T-shaped component and two plastic back up rings. The seals are used in reciprocating piston, rod and rotary applications. The T-shaped design prevents the elastomer rolling and the plastic back-up rings, energised by the rubber elastomer, provide improved high pressure performance. Importantly the T-seals can be installed into standard O-ring grooves. Other standard composite seal designs include spring reinforced seals, encapsulated seals, lip seals, energised lip seals and cap seals.

Where greater customisation is needed seal design engineering techniques based on popular CAD packages such as Solidworks, Catia, Pro Engineer and AutoCAD are employed. 3D modelling and analytical behaviour predictive tools such as finite element analysis (FEA) can then be used to explore ‘what if’ simulation scenarios to produce a ‘right first time’ design.

Seal selection tools to assist the engineer are also available sonline. Temperature and chemical compatibility, groove dimensions for the most common o-ring sizes, and physical performance datasheets enable selection of the most appropriate o-ring seal.

Seal customisation is possible for the physical properties of an elastomer. By making changes to the filler system it is possible to optimise the physical properties of a particular grade of material when compared to others within the same grade. The reinforcement effect of a filler is complex and dependent upon its structure, particle size and chemical make-up of the particles themselves.

In conclusion, the combination of online material selection tools, and application of seal engineering techniques, make it easier than ever for design engineers to optimise the specifications (and performance) of equipment rubber o rings and rubber seals.

Industrial Air Power Ltd is the authorised distributor for Ingersoll Rand Industrial Technologies products throughout Wales and the South West of England. The two companies have made a dramatic shift from being suppliers of equipment to providers of solutions. We are fully conversant with all aspects of air generation and equipped to carry out energy audits on any installed system, regardless of size or manufacturer.

A full system audit includes leak detection, measurement of energy consumption, and flow measurement including pressure, temperature and final air quality.

As utility rates continue to rise and firms continue to look to green initiatives, energy consumption has become a growing concern for manufacturers.

One of the largest energy users within a plant is the compressed air system. Energy recovery provides a cost-effective way for manufacturers to reduce their energy bills while simultaneously benefiting the environment by capturing the thermal energy created through the compression process and putting it to work. Where the heat produced from a compressor can be fully utilised, simple payback periods of less than two years are frequently achieved.

Having already worked with Carbon Trust on a variety of projects, Terram called on its expertise when faced with rising energy costs. The specialist manufacturer of geosynthetic materials, employing 95 staff at its manufacturing plant near Pontypool, worked with Industrial Air Power to eliminate energy inefficiencies and redesign and install a new air compressor system. The result was an industry best in terms of energy usage and savings of £202,000 per annum. It also produced:

* Energy savings of approximately 11.25 million kWh over five years
* Cost savings of approximately £1m in five years
* Emission savings of 7,390 tonnes CO2 in the same period
* Payback of approximately 24 months

David Roberts, control engineer at Terram Ltd, said: “The savings we are seeing now are unbelievable but just as important is the fact that we are reducing our carbon emissions and therefore benefiting the environment.”

Although Terram had already started to investigate the costs for new compressed air systems, it hadn’t looked at where, when, how much air was being used. Carbon Trust helped it identify this and used Industrial Air Power to design a system to meet its needs.

Having a tailor-made system installed in turn allowed Terram to capitalise on secondary savings such as heat recovery and compressed air leak reduction.

Ongoing monitoring of the fully automated system allows the savings to be quantified. Monitoring also ensures that the focus on savings is maintained and remains a high priority for Terram.

The new air compressors were located into the steam boiler house. This enabled Terram to recover the waste heat generated by the compressors and use this to raise the temperature of the water in the hot well, which feeds the boiler. Increased water temperature in turn reduces the amount of gas needed to generate steam.

The aggregated savings from the installation of the new system and implementation of the measures identified represented an 11.8 per cent reduction in the site’s energy consumption and overall a 38.7 per cent reduction in the electrical energy consumption directly associated with the generation of the compressed air.

An annual CO2 saving of 1,214 tonnes has been achieved plus an additional 264 tonnes from a reduction in gas usage due to the heat recovery process.

From monitoring the system, it was calculated that Terram was using on average 85m3/min of compressed air with an efficiency of 8kW/m/min, which equated to 7.2 million kWh per annum. By installing a new compressor set supplied by Industrial Air Power, it was calculated that the efficiency could be improved to 6kW/m3/min. Post-installation monitoring has proved that the new machinery provides an average efficiency of 5.8kW/m3/min – delivering significant savings. The gas savings are on top of this.

The benefits to Terram have been fourfold: a significant reduction in energy costs, the ability to protect plant integrity, reduced maintenance cost and the added benefit of reduced gas consumption from the increased water temperature in the steam boiler hot well.

Installing new Ingersoll Rand two stage fixed speed compressors along with a Nirvana two stage trim compressor, fully automated via a control system provided Terram with primary energy savings. Secondary savings came as a result of the heat recovery process, lower maintenance costs and the leak reduction programme.

The exercise has been successful in achieving reductions of CO2 emissions and the overall costs of supplying the service of compressed air to the business.

A Carbon Trust Wales consultant worked together with Industrial Air Power and Terram engineers providing impartial, independent advice enabling the company to make an informed decision and deliver value for money. Carbon Trust independently validated the energy savings and confirmed that they exceeded Industrial Air Power’s initial projections.

Through our experience in carrying out hundreds of compressed air audits we have identified the majority of existing compressed air systems include one or more of these deadly sins. This will have and adverse affect on your reliability, productivity and energy consumption.

* System over-pressurisation resulting in increased artificial demand
* Excessive waste through air leakage
* False loading of compressors due to lack of system automation and volume
* Inefficiency caused by cycling fixed output compressors
* Excessive pressure drop

If you would like advice on calculating your savings potential and increasing your company’s profitability contact Industrial Air Power on 01656 658961, email sales@airpower.co.uk

A UKAS temperature laboratory uses a range of reference platinum resistance thermometers, noble metal thermocouples, stirred liquid baths, specially designed isothermal calibration furnaces and black body sources to provide a comprehensive facility for cost effective thermometer calibration over the range -35ºC to 1,200ºC.

Both contact thermometers such as thermocouples, prts and dial thermometers; and non-contact infrared thermometers and thermal imaging cameras are covered. We can even calibrate temperature sources such a dry block calibrators or calibration baths.

The temperature calibration service company will also be able to offer stand alone UKAS calibration of digital thermometer readouts. As these are essentially an electrical instrument they are calibrated in the calibration services electrical laboratory.

The calibration uncertainties detailed below are typical examples of our best calibration and measurement capability for a reasonably repeatable thermometer. The final uncertainties quoted on the calibration certificate will include an allowance for the actual repeatability of the thermometer under test during the calibration. If the thermometer was submitted with its own readout and hence calibrated as a system, then an additional allowance will be included in the uncertainty budget to cover the resolution of the thermometer readout.

Indicating Thermometer Calibration (thermometer with readout, calibrated as a system). The device under test may be an electronic display with an attached probe. All thermometer probe types are covered, including PRT, thermistor or thermocouple. Dial thermometer and chart recorder type devices are also covered. The basic calibration uncertainty will be a little better than the uncertainties achievable for 4 wire PRTs, plus allowances for repeatability of the device under test and resolution of its readout.

Calibration of Infrared Thermal Imaging Camera (Thermal Imager)
Thermal imaging cameras that are able to display a measured radiant temperature should be calibrated. Our temperature ranges and uncertainties for UKAS calibration of a thermal imager will be similar to those quoted for an infrared thermometer calibration.

Dredging is required for various reasons including environmental, commercial and industrial uses.

Environmentally, examples of the use of dredging are to clear waterways also to collect sand in order to repair coastal erosion. Industrial and commercial uses dredging are for example the collection of materials used in concrete production and the dredging for valuable trace substances.

Dredging has become an essential operation in process of flood prevention through increasing an area’s capacity for holding or carrying water away.

Dredging requires not only the correct craft but also the correct dredging equipment which is mainly the dredging bucket. Each type of dredging project requires a different type of bucket as each location and material required to be dredged is different.

Dredging buckets are made by the process of the fabrication of steel through welding. They are either constructed in a workshop or onsite depending on the nature of the usage and location. Dredging buckets can range from 3m3 to 25m3. The first process is to design the bucket using CAD software and then the drawing service. It is these critical initial stages that enable the bucket to be fabricated.

The materials used in the construction of dredge buckets, excavator buckets and mining buckets are highly sophisticated. The steel is high strength and abrasion resistant with tungsten or chromium carbide wear protection systems. Each bucket is ESCO wear resistant encompassing their protection systems and are bushed and line bored.

As mining, dredging and excavation buckets are often used in challenging and demanding situations, it is important to keep on top of refurbishment. A professional dredge bucket manufacturer should also offer the service of repair and refurbishment.

The refurbishment and repair of mining and dredging buckets is as skilled a job as manufacturing. The welding and fabrication processes are as complex and so a fully equipped workshop is required with a lifting capacity in the region of 15 tonnes. The welding should be to ASMA 9 standard or higher with a mobile line boring facility. Once the welding and fabrication has been completed the process of the abrasion resistant and steel plate coatings can be implemented.