On-line leak sealing, on-site machining, in-situ safety relief valve testing & setting, hot tapping & line plugging, bolting services, pipe freezing, on-line ball/gate, valve servicing, flange/joint testing, pipeline composites repair. LEAK DETECTION/SEALING, OILFIELD SERVICE COMPANIES, ON-SITE MACHINING SERVICES, ESSEM HOLDINGS : On -Line Valve Servicing