Crude Oil Non-Pusher Secondary Seal

Abstract

Crude oil pipeline pumps traditionally suffer from seal leakage due to the fretting or wearing of the dynamic O-ring. A new concept secondary seal has been developed to eliminate this fretting occurrence. All major seal suppliers have products designed specifically for the operational challenges of crude oil pipeline services, some more than others recognize the application difficulties and have design characteristics that belie these. However none are designs based on non-pusher secondary seal concepts. A “non-pusher� style represents a targeted response to customer dissatisfaction and root cause of failure where crude oil is sealed. A more robust non-dynamic secondary seal cannot hang up and a non-dynamic secondary seal does not wear the stub sleeve. Site surveys and equipment Root Cause Analysis, have shown that solids & debris contained in the pumped product result in secondary seal damage and ultimately seal failure. Degradation of this secondary seal subsequently wears the stub sleeve making refurbishment more costly. Providing a more reliable secondary seal, especially as pumping stations that serve transmission and gathering pipe lines can be very remote and often unmanned, increases both pump and pipeline reliability. Reduced sleeve fretting maintains seal integrity, delivering improved spill prevention, and is valuable to operators in terms of assets protected as well as critical asset expansion. This paper will look at the design theory of a non-collapsible flexible sealing membrane, the subsequent successful development and testing of a non-pusher elastomer seal, and field deployment.