MechChem Africa March-April 2023

⎪ Products and industry news ⎪

The hygienic solution to pressure surges

Designed, engineered and manufactured in South Africa, Instrotech has designed a successful Acoustic Steam Leak Detection System (Inspecta ASLD) and has now developed a fully automatic purging system that’s easily retrofitted to exist ing Inspecta installations. The system eliminates routine manual purging of the pipe-sets and maintains the leak detec tion system at peak performance, without manual intervention. Installed in most ESKOM power sta tions, Inspecta ASLD systems use acoustic detection technology that detects tube leaks less than 2.0 mm in diameter in the large boiler structure. The coal used The Ingelfingen-based valve specialist GEMÜ has developed the GEMÜ 652 pulsation damper. Based on its tried and tested diaphragm valve technology, this damper is also suitable for use in sterile applications. It is completely drainable and CIP/SIP capable, taking the specified draining angle into account. In many production plants, unwanted pressure surges arise, which are generat ed by switching on pumps, by temperature changes in enclosed liquids or by quickly switching valves, for example. Opening valves can also result in pressure surges if the media supply is at a high level and the fluid column to lower plant components suddenly starts moving. These pressure surges may damage plant components, such as filters, sen sors, pumps and piping. Likewise, they can result in shut-off valves briefly opening inadvertently. This can, in turn, result in possible contamination of the medium. In

amount of fly ash remaining after combus tion. This fly ash swirls inside the boiler and quickly blocks the ‘listening’ pipe-sets that contain the sensitive leak-detection microphones. Unless the systems are frequently manually or automatically cleaned, their ability to detect the leaks early, is significantly degraded. To optimise effective leak detection operation, the pipe-sets, located particu larly in the combustion areas of the boiler, should be cleared of fly ash build-up every 1.5 to 2 hours. It is not practical to reli ably achieve this using a manual purging system. If the fly ash is allowed to build up, over a period of 5 to 6 hours, this will result in a serious deg the worst case, they can result in down time due to required repair work or a loss of product. As a solution to the problem, GEMÜ has launched the GEMÜ 652 pulsation damper, which is designed to open up as much volume as possible in a given operat ing range and thereby absorb and compen sate for the pressure surge. Its body does not include a sealing weir, meaning that it is not suitable for shutting off media. The actual expansion volume is made available by a moving diaphragm. By using different actuator sizes and spring sets, it is possible to adjust the op erating range and the volume that can be compensated for. Also, increased expan sion volume can be achieved by installing multiple pulsation dampers in series. The control air connector is only used for assembly. Actuation via control air is not required for operation, as its function is accomplished solely using spring force.

The GEMÜ 652 pulsation damper uses a moving diaphragm to absorb and compensate for pressure surges.

leak, the leak was detected promptly, the boiler was shut down before significant secondary tube damage had occurred and the resulting outage time was limited to 2 days before the boiler was brought back online. In the case of a delayed detection of a tube leak, however, the boiler shut down 2 hours after case 1. The leak progressed rapidly and created significant secondary damage, so that upwards of 40 tubes were damaged. From EPRI information (EPRI 2003), the boiler outage time increases steeply with secondary damage and it took 11 days to repair the boiler, which resulted in 11 days of lost electricity production. The Inspecta APS system can be in stalled into the current Inspecta ASLD configuration by simply replacing the existing Inspecta pipe-set with an Inspecta APS enabled one. All existing plant wir ing remains the same. This ensures the pipe-sets are automatically kept clear of fly ash and that the sensitivity of the Inspecta steam leak detection system is not compromised. This, in turn, will enable the system to reliably detect small tube leaks at a very early stage. Reducing downtime for leak repairs in a large generation unit by only one day delivers savings in electricity production loss that exceed the cost of the Inspecta APS system by ten-fold. Scan the QR code oppo site to find out more. www.instrotech.co.za The GEMÜ 652 pulsation damper is avail able in nominal sizes from DN 15 to DN 80 – diaphragm size 25 to 80. To ensure high flexibility of applications, the valve bodies and diaphragms are available in various materials and designs. Due to the diaphragm valve technology used, the product complies as standard with the current standards in the foodstuffs and pharmaceutical industry, such as BSE/TSE, FDA, USP Class VI and Regulation (EC) no. 1935/2004. www.gemu-group.com

Automatic purge system for power stations

by ESKOM is very high in ash con tent, so there is a considerable

radation in the leak detection sensitivity of the Inspecta ASLD. Under these degraded conditions, tube leaks may only be detected after pro gressing for some time. The resulting delay in de tecting a tube leak may well result in extensive secondary tube dam age and significantly extend the downtime to repair the damaged boiler. In one case of an early detection of a tube

The Inspecta APS Purge System, developed in South Africa by Instrotech, automatically keeps pipe-sets clear of fly ash to ensure that the sensitivity of the Inspecta steam leak detection system is not compromised.

38 ¦ MechChem Africa • March-April 2023