API STD 675:2014 pdf free download.Positive Displacement Pumps— Controlled Volume for Petroleum, Chemical, and Gas Industry Services
6 Basic Design
6.1 General
6.1.1 The Purchaser shall specify the period of uninterrupted continuous operation, during which time the equipment should not require shut down to perform maintenance or inspection.
NOTE 1 It is realized that there are some services where this objective is easily attainable and others where it is difficult. NOTE 2 Auxiliary system design and design of the process in which the equipment is installed are very important in meeting this objective.
6.1.2 Vendor shall advise in the proposal any component designed for finite life.
6.1.3 The Vendor shall assume responsibility for the pump and all auxiliary equipment included in the scope of the order.
6.1.4 The Purchaser shall specify the equipment’s normal operating point on the data sheets. Anticipated process variations that may affect this equipment (such as changes in pressure, temperature, or properties of fluids handled, and special plant startup conditions) shall be specified by the Purchaser.
6.1.5 Control of the sound pressure level of all equipment supplied shall be a joint effort of the Purchaser and the Vendor having unit responsibility. The equipment provided by the Vendor shall conform to the maximum allowable sound pressure level specified. If requested by the Purchaser, the Vendor shall provide data confirming compliance to the maximum sound pressure level specified.
6.1.6 Equipment shall be designed to run at the maximum rated input speed and relief valve settings simultaneously without damage. Vendor shall advise Purchaser of increased power operating requirements necessary to achieve this.
6.1.7 The arrangement of the equipment, including piping and auxiliaries, shall be developed jointly by the Purchaser and the Vendor. The arrangement shall provide adequate clearance areas and safe access for operation and maintenance.
6.1.8 Motors, electrical components, and electrical installations shall be suitable for the area classification (class, group, and division or zone) specified by the Purchaser and shall meet the requirements of the applicable sections of IEC 60079, or NFPA 70, API 500, and NEC as specified, as well as any local codes specified and supplied by the Purchaser.
6.1.9 Oil reservoirs and housings that enclose moving lubricated parts such as bearings, shaft seals, highly polished parts, instruments, and control elements shall be designed to minimize contamination by moisture, dust, and other foreign matter during periods of operation and idle periods.
6.1.10 All equipment shall be designed to permit rapid and economical maintenance, particularly regarding packing and valves. Major parts or components (such as the gearbox/drive, pump head, liquid end housing, and valves) shall be designed and manufactured to ensure accurate alignment on reassembly.
6.1.11 The pump design shall allow access for adjustment or replacement of liquid end components including packing, seals, check valves, and other wetted parts that require maintenance.
6.1.12 The check valves shall be removable from the liquid end for servicing or replacement. If removable spool pieces are required in the Purchaser’s piping to accomplish this, the Vendor shall so state in the proposal.
6.1.13 The equipment, including all auxiliaries, shall be suitable for operation under the environmental conditions specified by the Purchaser. The environmental conditions shall include whether the installation is indoors (heated or unheated) or outdoors (with or without a roof), maximum and minimum temperatures, unusual humidity, dusty, or corrosive conditions.
6.1.14 Spare and replacement parts for the machine and all furnished auxiliaries shall meet all the criteria of this standard.
6.1.15 The pump flow rate shall be adjustable over the specified turndown ratio while the pump is running.
6.1.16 Rated capacity shall be at least 110 % of the maximum capacity specified.
6.1.17 The steady state flow accuracy shall be within ± 1 % of rated flow over a turndown ratio of at least 10:1.
NOTE It should be recognized that this accuracy generally cannot be guaranteed below 10 percent of rated flow.
6.1.18 The flow repeatability shall be within ± 3 % of rated flow over the specified turndown ratio.
6.1.19 Deviation from linearity shall not exceed ± 3 % of rated flow over the specified turndown ratio.API STD 675 pdf download.API STD 675:2014 pdf free download
