Development of a Single Mechanical Seal equipped with a High-Pressure Containment Seal for Multiple Fluid Pipeline Pumps

LecturesThis paper discusses the critical design aspects, calculations, laboratory verification testing and field experience of a mechanical seal arrangement for multiple fluid Pipeline Pumps. The seal cartridge consists of a single wet lubricated mechanical seal on the product side in combination with a high-pressure containment seal on the atmospheric side. The single mechanical seal has been designed to operate in a product range from the flashing hydrocarbons ethane, propane, butane all the way up to non-flashing hydrocarbons like Natural Gasoline. Basically the single seal runs product lubricated in the media with a specific gravity range of 0,35 up to 0,65 and is designed for a pressure window up to 100bar, respecting the Pipeline Pressure. To assure this, a lift off of the mechanical seal faces at all media and at all operation conditions was targeted. To achieve this the functional components of the mechanical seal were subject of an extensive performance calculation and optimization with FEM (Finite Element Method. The mechanical seal concept includes a containment seal which withstands the full pipeline pressure in the unexpected event of a catastrophic mechanical seal failure of the single product side seal. This means massive leakage cannot leave the seal gland in an uncontrolled way under any case. To achieve similar safety and environment protection with a mechanical seal in a multiple fluid pipeline pump, conventionally a double pressurized mechanical seal with a pressurized supply system was needed. The proposed mechanical seal design provides a reliable pump sealing solution for these critical applications with a “single mechanical seal” in combination with a “high-pressure containment seal”. It provides the performance advantage and the safety philosophy of a double pressurized seal arrangement with the more costefficient single seal arrangement

Development of a Single Mechanical Seal Equipped With API Piping Plan 11/66a for Large Mainline Crude Oil Pipeline Pumps

Lectur

Development of a Single Mechanical Seal equipped with a High-Pressure Containment Seal for Multiple Fluid Pipeline Pumps

LecturesThis paper discusses the critical design aspects, calculations, laboratory verification testing and field experience of a mechanical seal arrangement for multiple fluid Pipeline Pumps. The seal cartridge consists of a single wet lubricated mechanical seal on the product side in combination with a high-pressure containment seal on the atmospheric side. The single mechanical seal has been designed to operate in a product range from the flashing hydrocarbons ethane, propane, butane all the way up to non-flashing hydrocarbons like Natural Gasoline. Basically the single seal runs product lubricated in the media with a specific gravity range of 0,35 up to 0,65 and is designed for a pressure window up to 100bar, respecting the Pipeline Pressure. To assure this, a lift off of the mechanical seal faces at all media and at all operation conditions was targeted. To achieve this the functional components of the mechanical seal were subject of an extensive performance calculation and optimization with FEM (Finite Element Method. The mechanical seal concept includes a containment seal which withstands the full pipeline pressure in the unexpected event of a catastrophic mechanical seal failure of the single product side seal. This means massive leakage cannot leave the seal gland in an uncontrolled way under any case. To achieve similar safety and environment protection with a mechanical seal in a multiple fluid pipeline pump, conventionally a double pressurized mechanical seal with a pressurized supply system was needed. The proposed mechanical seal design provides a reliable pump sealing solution for these critical applications with a “single mechanical seal” in combination with a “high-pressure containment seal”. It provides the performance advantage and the safety philosophy of a double pressurized seal arrangement with the more costefficient single seal arrangement

Comparison of contacting wet and dry gas seals for main pipeline pumps in NGL services

TutorialsRecent incident reports and studies of pipeline equipment indicate that pump seal performance is likely at the root of a significant increase in releases to the environment. Although these releases are small compared to a breach in a pipeline, they are of great concern to pipeline companies. While crude oil and refined fluid pipelines have been around for a long time, the pumping of natural gas liquids (NGLs) such as ethane, propane, butane and various mixtures of these liquids is relatively new and presents demanding challenges for the mechanical seal manufacturer and pump OEM’s. API (American Petroleum Institute) 682, the governing mechanical seal standard for mechanical seals in hydrocarbon services, is a great foundation for the sealing of process plant equipment. However, for pipeline services API 682 is of limited use due to more demanding operating conditions as well as the different operating character of pipeline pumps. Generally, two seal face lubrication technologies can be applied to seal NGL Pipeline Pumps with dual unpressurized seals: A contacting wet lubricated mechanical seal (2CW-CS / Arrangement 2 Contacting Wet – Containment Seal) A non-contacting Dry Gas Seal (2NC-CS / Arrangement 2 Non Contacting – Containment Seal) Both sealing solutions include a high-pressure non-contacting containment seal to protect the environment. Within this paper we discuss the general design aspects for two different sealing technologies, in particular the leakage and friction behavior in NGL services. The impact of critical operating parameters like vapor pressure and temperature margin, flush flow rates, ed. In addition, the safety, leakage containment and monitoring related aspects are described, summarized and compared with the mechanical seal recommendations

Development of a Single Mechanical Seal Equipped With API Piping Plan 11/66a for Large Mainline Crude Oil Pipeline Pumps

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The genomic and transcriptional landscape of primary central nervous system lymphoma

Primary lymphomas of the central nervous system (PCNSL) are mainly diffuse large B-cell lymphomas (DLBCLs) confined to the central nervous system (CNS). Molecular drivers of PCNSL have not been fully elucidated. Here, we profile and compare the whole-genome and transcriptome landscape of 51 CNS lymphomas (CNSL) to 39 follicular lymphoma and 36 DLBCL cases outside the CNS. We find recurrent mutations in JAK-STAT, NFkB, and B-cell receptor signaling pathways, including hallmark mutations in MYD88 L265P (67%) and CD79B (63%), and CDKN2A deletions (83%). PCNSLs exhibit significantly more focal deletions of HLA-D (6p21) locus as a potential mechanism of immune evasion. Mutational signatures correlating with DNA replication and mitosis are significantly enriched in PCNSL. TERT gene expression is significantly higher in PCNSL compared to activated B-cell (ABC)-DLBCL. Transcriptome analysis clearly distinguishes PCNSL and systemic DLBCL into distinct molecular subtypes. Epstein-Barr virus (EBV)+ CNSL cases lack recurrent mutational hotspots apart from IG and HLA-DRB loci. We show that PCNSL can be clearly distinguished from DLBCL, having distinct expression profiles, IG expression and translocation patterns, as well as specific combinations of genetic alterations

The genomic and transcriptional landscape of primary central nervous system lymphoma

Primary lymphomas of the central nervous system (PCNSL) are mainly diffuse large B-cell lymphomas (DLBCLs) confined to the central nervous system (CNS). Molecular drivers of PCNSL have not been fully elucidated. Here, we profile and compare the whole-genome and transcriptome landscape of 51 CNS lymphomas (CNSL) to 39 follicular lymphoma and 36 DLBCL cases outside the CNS. We find recurrent mutations in JAK-STAT, NFkB, and B-cell receptor signaling pathways, including hallmark mutations in MYD88 L265P (67%) and CD79B (63%), and CDKN2A deletions (83%). PCNSLs exhibit significantly more focal deletions of HLA-D (6p21) locus as a potential mechanism of immune evasion. Mutational signatures correlating with DNA replication and mitosis are significantly enriched in PCNSL. TERT gene expression is significantly higher in PCNSL compared to activated B-cell (ABC)-DLBCL. Transcriptome analysis clearly distinguishes PCNSL and systemic DLBCL into distinct molecular subtypes. Epstein-Barr virus (EBV)+ CNSL cases lack recurrent mutational hotspots apart from IG and HLA-DRB loci. We show that PCNSL can be clearly distinguished from DLBCL, having distinct expression profiles, IG expression and translocation patterns, as well as specific combinations of genetic alterations

The influence of perivascular tissue on lateral thermal expansion during bipolar vessel sealing

Background: Lateral heat propagation has been an unavoidable effect of bipolar sealing with the risk of damage to surrounding structures. It is presently unknown whether leaving the perivascular tissue in situ may be advantageous in the sense of an isolation effect. Material and methods: Two groups were formed from ex vivo carotid specimens. Group A (n = 10) consisted of carotid artery with the perivascular connective tissue in place (mean preparation diameter: 10.57 ± 0.16 mm) and group B (n = 10) of skeletonized carotids (mean vessel diameter: 5.21 ± 0.12 mm). All specimens were fixed on a plastic plate and mounted vertically in a holder. Sealing was performed perpendicular to the axis of the specimens. The temperature during the sealing process was recorded by a thermal camera. Group comparison was performed by a nonparametric test and significance was set at p < 0.05. Results: Mean sealing time in group A was 3.71 ± 0.37 s compared to 3.42 ± 0.37 s (p = 0.009) in group B. The maximum temperature in the middle of the jaws was significantly different. Group A had a temperature of 71.4 ± 3.9 °C and group B had a temperature of 91.4 ± 7.4 °C (p < 0.0001). RILATE risk scores (percent of necrotic zone in relation to potential area of necrosis) at both upper and lower sides of instrumental jaws were significantly different. For group A, it was 14.9 ± 1.6 at the upper side of jaws, 20.4 ± 2.63 at the lower side of jaws and for group B, it was 21.9 ± 3.5 at the upper side of jaws, 30.2 ± 6.2 at the lower side of jaws. Conclusion: Perivascular connective tissue acts as an insulator with respect to lateral heat propagation. Peak temperature between instrument jaws is significantly reduced with perivascular tissue in situ. This may result in a negative impact on sealing quality

Detection of the Lateral Thermal Spread during Bipolar Vessel Sealing in an Ex Vivo Model&mdash;Preliminary Results

Background: As an unwanted side effect, lateral thermal expansion in bipolar tissue sealing may lead to collateral tissue damage. Materials and Methods: Our investigations were carried out on an ex vivo model of porcine carotid arteries. Lateral thermal expansion was measured and a calculated index, based on thermographic recording and histologic examination, was designed to describe the risk of tissue damage. Results: For instrument 1, the mean extent of the critical zone &gt; 50 &deg;C was 2315 &plusmn; 509.2 &micro;m above and 1700 &plusmn; 331.3 &micro;m below the branches. The width of the necrosis zone was 412.5 &plusmn; 79.0 &micro;m above and 426.7 &plusmn; 100.7&micro;m below the branches. For instrument 2, the mean extent of the zone &gt; 50 &deg;C was 2032 &plusmn; 592.4 &micro;m above and 1182 &plusmn; 386.9 &micro;m below the branches. The width of the necrosis zone was 642.6 &plusmn; 158.2 &micro;m above and 645.3 &plusmn; 111.9 &micro;m below the branches. Our risk index indicated a low risk of damage for instrument 1 and a moderate to high risk for instrument 2. Conclusion: Thermography is a suitable method to estimate lateral heat propagation, and a validated risk index may lead to improved surgical handling

An expert consensus definition of failure of a treatment to provide adequate relief (F-PAR) for chronic constipation \u2013 an international Delphi survey

Background: As treatments for constipation become increasingly available, it is important to know when to progress along the treatment algorithm if the patient is not better. Aim: To establish the definition of failure of a treatment to provide adequate relief (F-PAR) to support this management and referral process in patients with chronic constipation. Methods: We conducted an international Delphi Survey among gastroenterologists and general practitioners with a special interest in chronic constipation. An initial questionnaire based on recognised rating scales was developed following a focus group. Data were collected from two subsequent rounds of questionnaires completed by all authors. Likert scales were used to establish a consensus on a shorter list of more severe symptoms. Results: The initial focus group yielded a first round questionnaire with 84 statements. There was good consensus on symptom severity and a clear severity response curve, allowing 67 of the symptom-severity pairings to be eliminated. Subsequently, a clear consensus was established on further reduction to eight symptom statements in the final definition, condensed by the steering committee into five diagnostic statements (after replicate statements had been removed). Conclusions: We present an international consensus on chronic constipation, of five symptoms and their severities, any of which would be sufficient to provide clinical evidence of treatment failure. We also provide data representing an expert calibration of commonly used rating scales, thus allowing results of clinical trials expressed in terms of those scales to be converted into estimates of rates of provision of adequate relief