# US 11,079,021 B2 · Barrier system for mechanical seal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,021 B2 - Document ID: US11079021B2 - Status: Granted - Kind: B2 - Application number: 14/301,671 - Filed: 2014-06-11 - Published: 2014-12-18 - Granted: 2021-08-03 - Earliest claimed: 2013-06-12 - Applicants: AES Engineering Ltd. - Inventors: Andrew John Stoney - Web page: https://patentgrep.com/patent/US11079021B2 ## CPC - F16J 15/40: by means of fluid - F15B 1/08: using a gas cushion; Gas charging devices; Indicators or floats therefor - F16J 15/16: between relatively-moving surfaces (F16J15/50, F16J15/52 take precedence; bellows pistons F16J3/06; piston-rings or ring sealings of similar construction F16J9/00) - F15B 2201/3152: the flexible separating means being bladders - F15B 2201/4155: having valve means - F15B 2201/50: Monitoring, detection and testing means for accumulators - F15B 2201/51: Pressure detection - F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR ## Abstract A barrier system for a dual mechanical seal, the system comprising means for controlling barrier fluid pressure relative to product pressure. The pressure control means comprises means for monitoring the volume of barrier fluid in the system and for supplying additional fluid to the system to maintain the volume within a desired range. The system further comprises means for maintaining the barrier fluid pressure at a pre-determined pressure above product pressure. ## Claims ### Claim 1 A barrier system comprising: a dual mechanical seal comprising a pair of seals with a barrier seal chamber between the pair of seals, wherein the barrier seal chamber has a barrier seal pressure (Pbarrier); and, a controller comprising a product pressure reference (Pref) input, a valve output controlling flow of a barrier fluid into the barrier seal chamber, and pre-determined pressure (Pbias) setting above the product pressure reference (Pref); wherein the controller is configured to track the Pbarrier and control the barrier fluid flow to maintain the Pbias in the barrier seal chamber over the product pressure; wherein the controller further comprises a volume monitor adapted to monitor a volume (Vbarrier) of barrier fluid in the system; and, wherein the volume monitor comprises one or more flow meters selected from the group consisting of: a flow meter between a bladder accumulator and the barrier seal chamber; a flow meter receiving fluid flowing from the barrier seal chamber; a pair of flow meters with one of the pair upstream to the barrier seal chamber and one of the pair downstream from the barrier seal chamber; and three flow meters. ### Claim 2 (depends on 1) The barrier system of claim 1, wherein the pair of seals are spaced along a shaft. ### Claim 3 (depends on 1) The barrier system of claim 1, wherein a product having the product pressure is in contact with one of the pair of seals on a side opposite the barrier seal chamber. ### Claim 4 (depends on 3) The barrier system of claim 3, wherein the product having the product pressure is in direct contact with at least one of the seals. ### Claim 5 (depends on 1) The barrier system of claim 1, wherein the controller is adapted to provide the pressure in the barrier seal chamber of Pbias over the product pressure when the product pressure reference (Pref) input is zero. ### Claim 6 (depends on 5) The barrier system of claim 5, wherein the controller is adapted to control flow of the pressurized gas through a valve to a barrier fluid accumulator which provides barrier fluid to the barrier seal chamber. ### Claim 7 (depends on 6) The barrier system of claim 6, wherein the flow of the pressurized gas through the valve controls the Pbarrier of the barrier seal chamber. ### Claim 8 (depends on 7) The barrier system of claim 7, further comprising a bladder accumulator adapted to receive the pressurized gas and provide the barrier seal chamber with a barrier fluid at Pbarrier. ### Claim 9 (depends on 1) The barrier system of claim 1, wherein the volume monitor is adapted to monitor a volume of barrier fluid consumed by leakage through the seals. ### Claim 10 (depends on 1) The barrier system of claim 1, wherein the system is configured to monitor the barrier seal chamber pressure and increase the barrier seal pressure when the Pbarrier is less than the Pref plus the Pbias. ### Claim 11 (depends on 1) The barrier system of claim 1, wherein the controller is adapted to maintain the Pbarrier at a Pbias above the Pref, and adapted to monitor the (Vbarrier) in the system and supply additional fluid to the system to maintain the (Vbarrier) within a desired range. ### Claim 12 (depends on 11) The barrier system of claim 11, wherein the controller is adapted to receive pressure readings from the product and from the barrier fluid; and wherein the controller releases pressure from the barrier system when the Pbarrier is above Pref plus Pbias. ### Claim 13 (depends on 1) The barrier system of claim 1, wherein the system is adapted to maintain Pbarrier at Pref plus Pbias. ### Claim 14 (depends on 1) The barrier system of claim 1, wherein the barrier fluid is a liquid. ### Claim 15 (depends on 1) The barrier system of claim 1, wherein the volume monitor comprises a flow meter measuring a loss of fluid through the barrier seal chamber. ### Claim 16 (depends on 1) The barrier system of claim 1, wherein the product pressure reference (Pref) input comprises a tracked product pressure. ### Claim 17 (depends on 1) The barrier system of claim 1, wherein the pre-determined pressure (Pbias) setting above the product pressure has a value greater than zero.