Initially pump head for a particular flow is decided after calculating the system head (combination of static lift and frictional losses). When the pipes are new or an error occured in calculation, actual system head will be lower than calculated system head. So if no additional frictional loss...
The use of hydraulic submersible or vertical line shaft pumps depends on where it is installed and cost. On semisubmersible platforms, hydraulic submersible pumps are used where vertical line shaft pumps and horizontal direct driven pumps cannot be installed. On fixed platforms, vertical line...
It was observed that pump Vendor had installed an orifice in the cooling water line to gear box cooler of very small diameter which can flow only 1/4th of designed flow. The orifice diameter is increased to more than double which as per calculations can provide the required flow. The testing is...
Thanks for al the input. Will inform the final findings once Vendor comes out with any suggestions (like increase of setting height, increase of cooling water flow, reduction of engine and pump speed) and implementation to reduce the temperature within a rise of 40 Deg C above ambient. Right now...
Gear Box Vendor is the sub Vendor of Pump Vendor. Hence we do not have direct contact with Gear Box Manufacturer. Gear box was selected for the downthrust provided by Vendor. My point is if downthrust disappears due to contact between impeller and casing at bottom (due to shaft extension during...
As the performance curves are different for fixed speed steam turbine driven pump and VFD / Motor driven pumps, the capacity sharing will not be equal. As all the pumps were working in parallel before, one will assume the drivers are rated for end of curve power. From the system...
This issue was discussed with Gear Box manufacturer and their recommendation is to use mineral oil with change in every 3 months and synthetic oil with change in every 6 months. The cooling water flow is 42 lpm. One factor they might be missing is functioning of thrust bearing of gear box which...
API 610 is followed for pump design and construction. For performance selection, NFPA 20 is followed. Is bearing oil temperature as high as 112 Deg C accepable at site conditions. API 610 allows maximum 93 Deg C. Gearbox manufacturer recommends mineral oil for temperature upto 82 Deg C and...
As per API 610, 11th Edition, Clause 6.10.2.4b - For ring oil or splash system, oil sunp temperature below 82 Deg C (180 Deg F). During shop testing, the pump oil temperature shall not exceed 40K (70 Deg R) and (if bearing temperature sensors are supplied) outer ring temperature shall not exceed...
As the intention is to reduce head for the same flow for motor driven pumps by the use of VFD, steam turbine driven pump with constant speed ( high head)will deliver the major share of total flow. So it is possible to operate 4 pumps in parallel. But instrumentation is not clear. Unless some of...
When engine driven vertical turbine type fire water pup is shop tested, right angle gear box temperature is found to be 62 deg above ambient for radial bearing and 42 deg above ambient for thrust bearing. Pump is 5000 gpm capacity with head of 132 m. Same temperature is found in similar 4 pumps...
Nonflow test is running the pump at shut off with discharge valve closed. Only the recirculation valve flow for motor driven pumps and cooling water flow for engine cooling are permitted. My concern is running such high capacity (5000 gpm) pumps at shut off with NFPA 25 permitted water flow may...
Thanks LiitleInch, bimr and Artisi. NFPA 25 requirements are more clear now. NFPA 25, 2014 Edition Clause 8.3.1.2 requires "A nonflow test shall be conducted for electric motor fire pumps without recirculating water to the pump suction .." and Clause 8.3.2.1 requires "A test of fire pump...
Dear LittleInch,
Thanks. Vendor confirms that pump can work at about 6 m3/hr flow ( flow for a 1" relief valve). We requested Vendor to measure vibration during shop test at 6 m3/hr flow, but Vendor is not agreeing. Instead pump will be opened and checked for any rubbing after test since NFPA...
Hi,
We have a motor driven horizontal split casing (BB1)fire water pump in a new project under construction with rated capacity = 1136 m3/hr, Head = 131.5 m, Motor rating = 780 kW. As per NFPA 20, only a 1" relief valve is provided for minimum thermal flow. As per NFPA 25, pump is to be tested...
