Seal flush

Figure 3-31A. Typical seal flush arrangement for double mechanical seals.

Maximum Allowable Working Pressure, code, 399, 405, 406, 408 Mechanical seals, 171-177 Fundamentals, 172 Inside, 172 Installations, 173 Lubrication, 174 Outside, 173 Seal flush system, 176 Tandem, 177... 

All pipes which pass through walls should be sealed flush to the surface. 

Recycle Line Problems Seal Flush Problems... 

Syngas Homologation of Acetic Acid. To a N2-flushed liquid mix of acetic acid (50.0 gm) and methyl iodide (5.67 gm, 40 mmole), set in a glass liner is added 0.763 gm of ruthenium(IV) oxide, hydrate (4.0 mmole). The mixture is stirred to partially dissolve the ruthenium and the glass liner plus contents charged to a 450 ml rocking autoclave. The reactor is sealed, flushed... 

The autoclave was sealed, flushed with hydrogen and pressurized with 10 MPa of hydrogen. The mixture was stirred for 18 hours at 20 °C under 10 MPa of hydrogen. 

When a mechanical seal is specified, it shall be located at the cover plate to seal the vapor in the supply tank or vessel. Mechanical seals normally seal vapor however, they shall be designed to operate in liquid in the event of tank or vessel overfilling. With purchaser approval, the vendor may supply a seal pressurized by flush from the pump discharge or from an external source. External seal flush must be compatible with the liquid being pumped. The seal chamber shall have provisions for a high point vent. 

Zl FLOW RATE (GPM) SEAL FLUSH PIPING (2.7.3.19 AND APPENDIX D) 0 SEAL FLUSH PIPING PLAN... 

FLUID IS INJECTED INTO THE SEAL CHAMBER FROM AN EXTERNAL SOURCE. CARE MUST BE EXERCISED IN CHOOSING A PROPER SOURCE OF SEAL FLUSH TO EUMINATE THE POTENTIAL FOR VAPORIZATION OF THE INJECTED FLUID AND TO AVOID CONTAMINATION OF THE PUMPAGE WITH THE INJECTED FLUSH. ( DIAL THERMOMETER AND ROW INDICATOR ARE OPTIONAL). 

To avoid shortening seal life, consideration must be given to evolution of gas and vaporization in seal flushing streams. Where this potential exists, a seal flush from other than the HPRT inlet is generally recommended. 

A325 Seal flush pipe plan SEAL PI PL C 1 A.none BiAPI Plan 1 C API Plan 2 ... 

Seal glands and seal chambers shall have provision for only those connections required by the seal flush plan. If additional tapped connection points are specified and are not used, they shall be plugged in accordance with 5.4.3.7. 

The pump and seal chamber shall be continuously vented with a high point connection in either the seal chamber or seal flush piping. Systems needing manual venting require purchaser approval. 

To a 300 mL Hastelloy-B autoclave was added 110 mL (87.0 g, 2.71 mol) of methanol, 30.0 mL (23.3 g, 126 mmol) of tributyl amine, 11.0 mL (11.3 g, 83.8 mmol) of 1-chloropinacolone, and 0.1 mmol of catalyst. The autoclave was sealed, flushed with carbon monoxide, and pressurized to 30 psi with CO. The autoclave was then heated to 105°C and the pressure was adjusted to 80 psi. The temperature and pressure were maintained using a continuous carbon monoxide feed for 3 h. The mixture was then cooled and analyzed by gas chromatography. Phosphine effects and additional comparison were conducted at 150 psi of CO as noted in the tables. 

Provide seal flush kit including valves, tubing and gauges as required for WFI Service... 

Answer—there is an error in the design of this pump. The error is that this is a self-flushed pump. The mechanical seals on centrifugal pumps require a lubricant or seal flush material to keep the seal faces from touching and rubbing. In most pumps, this seal flush fluid comes from the discharge of the pump itself. Such pumps are called self-flushed pumps. 

When a self-flushed pump is running, the space between the seal faces is filled with the seal flush fluid. When the pump is shut down, the space between the seal faces is filled with the fluid in the suction of the pump. However, if the pressure at the suction of the pump is below atmospheric pressure, then air is drawn through the seal faces and into the suction of the pump. This air displaces the water in the pump s case and, with time, causes the pump to lose its prime. 

To fix this problem in Port Arthur, I connected an external source of seal flush water to the pump, from a nearby washwater station. Pumps which have subatmospheric suction pressures, and which are not in continuous service, should not be self-flushed pumps. They should have an external source of seal-flush material connected to the mechanical seal. 

As mentioned above, the defective pump was shut down early Monday morning before sunrise, and the mechanics started work about 10 30 A.M. on Tuesday, after the equipment was locked out. The pump was idle for about 28 hours before the well water seal flush was disconnected and the mechanics started disconnecting the 400-hp electric motor. 

The water circulation pump must be of sanitary design and may be equipped either with a single or a double mechanical seal. In the latter case, the purified water from the pump s discharge is used as a seal flush fluid (Fig. 5). If a spare circulation pump is installed for reliability, it is important to ensure that it does not constitute a long dead leg. This can be avoided either by valving it off and draining it free of water... 

Product from pump outlet throttled to 1-2 GPH at 2-S PSI for seal flush water supply... 

When the vacuum valve closes, its auxiliary contacts open causing interruption of the cir-cnits to the recirculation pump and pressure control pump motor starters. Auxiliary contacts in the starters open, intermpting the circuit to the seal flushing water solenoid valve and the remotely mounted control relay. The control relay is de-energized stopping the feed pump and macerator. 

To aid cleaning, all electrical cables and ducting for other services should be installed deep in cavity walls where they are accessible for maintenance but do not collect dust. All pipes that pass through walls should be sealed flush to the surface. 

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