Field Engineering Bulletin - Sundyne

1 14845 West 64th Avenue, Arvada, Colorado 80007 USA Tel: 303-425-0800 Fax: 303-425-0896 Bulletin No. Sunflo Pump seal Plans EFFECTIVE: APRIL 11, 2006 Rev: A An overriding majority of pump problems are not with the pump, but with the mechanical seals. Pump mechanical seals need three conditions for successful operation: 1. Clean Liquid 2. Cool Liquid 3.

2 Low Pressure Liquid The single seal auxiliary kit drawings are used to provide any one or all of these requirements for single seal pumps. Process fluid is altered to satisfy the mechanical seal , and then reunited with the main stream inside the pump. There is no loss in net flow rate, and no contamination of the process from external sources. The environmental seal plans should be employed based on past experience and common sense. Many applications will not require that an auxiliary system be used for the mechanical seal . However, when a customer inquires about a harsh service or experiences repeated seal failures, it is important to supply the proper environmental seal kit.

3 Consult the factory whenever necessary. Although these kits will resolve a majority of seal problems, the following guidelines apply to double and tandem seals used for severe services. DOUBLE seal APPLICATIONS Double seals should be used whenever the single seal auxiliary kits prove unsuccessful. Hot water applications (in excess of 260 F (127 C)) always require double seals. Water services between 180 F (82 C) and 260 F (127 C) can use double seals if process cooling cannot be tolerated. Conversely, the single seal cooling plans 21 & 41 can be used with double seals above 260 F (127 C) as long as the heat exchanger is resized for adequate cooling and the buffer outlet can be plumbed into the pump suction line.

4 Finally, double seals are an excellent method for sealing hazardous or poisonous liquids that cannot leak into the workmen s environment. Double seals must have a pressurized buffer system (15 psig (1 bar) above seal cavity pressure) that circulates approximately 2 gpm ( l/m) of process compatible buffer fluid. A Plan 53 is normally used with double seals. The buffer fluid should be cool water, seal oil, or some other liquid that is easy for the mechanical seals to handle. TANDEM seal APPLICATIONS Tandem seals may be used instead of a single seal for leak detection and backup.

5 Typically, an atmospheric buffer system is employed with provision for self-circulation or forced circulation of to 2 gpm ( to l/m) required to control the seal temperature. The buffer may be cool water, oil or other suitable non-volatile liquid. Field Engineering Bulletin Title: Sunflo Pump seal Plans Rev A Bulletin No. Page 2 of 13 A description of the auxiliary seal kit numbering system will aid in selecting the proper seal kit. KF XX XX XX Kit, Flush (Single seals only)

6 Similar to API Plan 11 12 13 Pump Model Number 21 FL = P-1000 23 = P-1500 Varies Note 1 31 UT = P-2000 32 SP = P-3000 41 52 53 Note 1: Varies based on process conditions, heat exchanger, etc. Refer to individual kit drawings for specific information about orifice sizing, flush flow rate, maximum pressure, and maximum temperature limits. seal FLUSH PLANS Below is a brief description of the seal flush plans available for Sunflo pumps.

7 PLAN 11 This kit circulates process fluid from the pump discharge, through an orifice, then into the seal cavity. It maintains an ample supply of gas-off when the seal cavity pressure is below atmospheric pressure. Plan 11 is recommended when vacuum can be detected in the seal flush port during pump operation. This occasionally occurs on low suction pressure units (less than 20 psig ( bar)) that do not have an inducer. PLAN 12 Plan 12 is similar to plan 11 except a filter or strainer is added to the flush line.

8 This kit is used to provide a clean seal flush in the event the product contains abrasives or fouling material which cannot be removed by a centrifugal separator. Satisfactory seal life may be achieved by filtering to a maximum particle size of two microns. The orifice must be sized to allow 1 to 2 gpm ( to l/m) of clean product flow into the seal flush port. This kit may be helpful in machine tool coolant service and paper shower service (where the water contains wood pulp). Title: Sunflo Pump seal Plans Rev A Bulletin No. Page 3 of 13 PLAN 13 Plan 13 is similar to plan 11 except the flow exits the seal chamber and returns to the pump suction.

9 This auxiliary seal kit recirculates liquid and entrained vapors from the seal cavity chamber, through a tubing orifice, then back to the pump suction. The amount of recirculation is regulated by the inch ( mm) tubing inside diameter and the length specified on each kit drawing. This kit provides maximum circulation around the mechanical seal face and helps to ensure that liquid, not vapor, is available at the seal faces. Plan 13 is recommended for light hydrocarbon services and any other time the process vapor pressure is above atmospheric pressure.

10 It can be helpful whenever a centrifugal separator is ineffective; such as saltwater processes and applications involving suspended wood particles. Refer to the Plan 31 description for further details. PLAN 21 Plan 21 is similar to plan 11 except with cooling. This auxiliary seal kit causes the vapor pressure of fluid in the seal cavity to be below atmospheric pressure when the remainder of the pumpage is not. Allowance is made for friction reheating the fluid as it crosses the mechanical seal face so that the fluid remains in the liquid phase. A small portion of liquid is tapped off the pump discharge then forced through an orifice, heat exchanger, and to the seal cavity.