Gear Pump for Oil

It is a positive displacement pump in which two gears turn inside a casing. The drive shaft receives the motor's rotation and turns the other gear. Meshing creates a depression in the suction chamber, the oil fills the cavities between the teeth and the casing and is carried around the periphery to the discharge. The meshing itself prevents return to suction, so pumping is continuous (2026 FBE catalogue, p.2). In the FBE series, the body is cast in a single piece, with feet and ports opposed at 180°. The gears have helical teeth, the shafts run in bushings and the seal sits at the front of the pump (MTEC-01/01, p.1 and p.6). The manual covers sizes from 1/8″ to 6″, with flows up to 390 m³/h; the 2026 catalogue also lists the 10″ on p.6. The 2026 catalogue gives a range of 30 to 100,000 SSU and discharge pressure up to 22 kgf/cm². These are series limits: each size has its own, and they do not apply at the same time.

• Petrochemicals, oil and gas: in refineries, diesel oil, crude oil, greases, kerosene, gasoline and oils in general (2026 FBE catalogue, p.3).
• Metalworking: hydraulic machines and equipment, filter presses, lubrication systems and oil burners (2026 FBE catalogue, p.3).
• Food: BPF fuel oil and vegetable oil are on the catalogue list, alongside syrups, molasses and glucose (2026 FBE catalogue, p.3).
• Outside these lists, the application is confirmed with the oil data sheet and the process data.

The oil's name does not select the pump. What selects it is the viscosity at the temperature at which it will be pumped, the flow, the pressure and the suction. A light hydraulic oil and a heavy fuel oil can use the same FBE series, but on different rows of the speed table: the light oil can run at 1,750 rpm with direct drive, while the heavy oil may need 850 rpm or a pulley and reducer. New, used and blended oils require different descriptions. For used oil, report water, particles and known contaminants: the MTEC-01/01 manual requires consulting FB when the fluid carries suspended solids (item 2.3). For oil that thickens or solidifies as it cools, report the minimum site temperature and the available heating.

• Lubricating oil: ISO VG grade, additives, circuit and startup temperatures.
• Hydraulic oil: the pump's role in the circuit, actual service pressure and reservoir temperature.
• Heavy fuel oil (BPF): startup and running viscosity and available heating, which can be the FBE heating chamber from 1.1/2″ to 6″.
• Vegetable oil: composition, temperature and contact and cleaning requirements.
• Used oil: water, particles and known contaminants, so that FB can assess the suspended solids.

The ISO VG grade classifies oil by kinematic viscosity at 40 °C, in cSt (mm²/s), and says nothing about any other temperature (ASTM D2422, items 1.2 and 4.4). The FBE speed table is in SSU. The 2026 FBE catalogue (p.5) gives the approximate conversion SSU = cSt × 4.635, valid above 300 SSU, that is, above about 65 cSt. Example 1: an ISO VG 68 oil has about 68 cSt at 40 °C, or 68 × 4.635 ≈ 315 SSU. Pumped at 40 °C, it falls on the 250 to 2,500 SSU row: 1,150 rpm, direct drive, FBE 1/8″ to 5″. Example 2: an ISO VG 680 has about 680 cSt at 40 °C, or ≈ 3,150 SSU, and falls on the 2,500 to 7,500 SSU row: 850 rpm, direct drive, FBE 1/2″ to 6″. If the oil is pumped colder, viscosity rises and the row may change; the oil data sheet gives the viscosity at the actual temperature. Below 300 SSU, use the catalogue conversion chart or the viscosity calculator.

• 30 to 250 SSU: 1,750 rpm, direct, FBE 1/8″ to 1″D.
• 250 to 2,500 SSU: 1,150 rpm, direct, FBE 1/8″ to 5″.
• 2,500 to 7,500 SSU: 850 rpm, direct, FBE 1/2″ to 6″.
• 7,500 to 10,000 SSU: 700 to 500 rpm, with pulley or reducer, FBE 1.1/2″ to 6″.
• 10,000 to 50,000 SSU: 500 to 300 rpm, with pulley or reducer, FBE 1.1/2″ to 6″.
• 50,000 to 100,000 SSU: 300 to 150 rpm, with pulley or reducer, FBE 3″ to 6″ (2026 FBE catalogue, p.5).

Viscosity sets the table row, and the row limits the sizes. According to the catalogue table, FBE 1/8″ and 1/4″ go up to 2,500 SSU; 1/2″ to 1″D, up to 7,500 SSU; 1.1/2″ and 2″, up to 50,000 SSU; and 3″ to 6″, up to 100,000 SSU. Each model's flow, by speed and pressure, is in the catalogue and manual tables. Do not extend one size's range to the others. Power rises with viscosity, because oil friction adds to the hydraulic power (Hydraulic Institute). The 2026 FBE catalogue (p.5) gives the efficiency η by viscosity and pressure. With flow Q in m³/h and pressure Δp in kgf/cm², shaft power is P (cv) = Q × Δp ÷ (27 × η), where cv is metric horsepower. Example: 6 m³/h, 7 kgf/cm² and 3,000 SSU, with η = 0.32 from the table, give 6 × 7 ÷ (27 × 0.32) ≈ 4.9 cv. With the 30% reserve for the 3 to 5 cv band, the commercial motor must have at least 6.3 cv. Between two viscosity columns, the more viscous column gives the lower efficiency and the safer result. Viscosity also changes the inlet pressure the pump requires, which is why suction is part of the enquiry.

• Efficiency η at 7 kgf/cm²: 40% at 1,000 SSU, 32% at 3,000 SSU, 26% at 7,000 SSU, 20% at 30,000 SSU and 17% at 50,000 SSU (2026 FBE catalogue, p.5).
• Efficiency η at 15 kgf/cm²: 45% at 1,000 SSU, 42% at 3,000 SSU and 28% at 50,000 SSU (2026 FBE catalogue, p.5).
• Motor power reserve: 50% up to 2 cv, 30% from 3 to 5 cv, 25% from 6 to 10 cv, 15% from 11 to 25 cv and 10% above 25 cv (2026 FBE catalogue, p.5; MTEC-01/01, Table 4).

The 2026 FBE catalogue lists the FBE in lubrication systems and in hydraulic machines and equipment, and in refineries for oils in general (p.3). In circulation duty, selection starts from the circuit flow, the pressure at the most demanding point and the oil's viscosity at operating and startup temperatures. When the same pump moves oils of different grades, such as ISO VG 68 and ISO VG 680 in the same circuit, the speed must fit the table row of the most viscous oil. From the examples above, at 40 °C that takes it from 1,150 rpm to 850 rpm. Flow and power are checked at both extremes. When replacing the oil pump of a gearbox, compressor or turbine, the FBE only replaces the original after flow, pressure, speed, direction of rotation, connections and mounting have been checked. Port size alone does not establish equivalence.

The 2026 FBE catalogue (p.3) lists the series materials. Casing and covers can be ASTM A48 CL30 cast iron, ASTM A536 60-40-18 ductile iron, ASTM A216 WCB carbon steel or ASTM A743 CF8M stainless steel. Shafts and gears are SAE 1045 steel or AISI 316L stainless steel, with special treatments on request. Bushings can be self-lubricating bronze, cast iron, PTFE (Teflon), graphite or babbitt metal. The choice follows the oil, temperature, pressure and contaminants, not a rule by oil name. Sealing is also chosen by fluid (MTEC-01/01, items 2.3 to 2.7). The packing is compressed by the gland and adjusted with a hex nut. The standard mechanical seal is type 21, in ceramic × graphite × Viton, with an AISI 304 stainless spring. The lip seal sits in a specially made cover or casing. The magnetic coupling is the special seal for when no leakage is allowed, as with corrosive, toxic or explosive fluids. Seal flush and quench are made according to the application and the customer's request (Table 17).

FB supplies two drive configurations for the FBE, both on a metal baseplate with a flexible coupling: direct to the electric motor or direct to the gear motor (2026 FBE catalogue, p.4). Above 7,500 SSU, the speed table calls for a pulley or reducer. The manual provides for an electric or combustion engine drive, a coupling with or without spacer, a coupling guard in carbon steel or non-sparking material and a baseplate in welded structural steel or U-channel plate (MTEC-01/01, p.7). For oil that thickens or solidifies as it cools, the pump must be kept warm. The heating chamber (CA variant) exists from FBE 1.1/2″ to 6″. The internal relief valve is a catalogue accessory, in brass or AISI 304 stainless steel.

• Ports: BSP thread from 1/8″ to 1″; ANSI B16.5 150 lb flanges from 1.1/2″ upward (2026 FBE catalogue, p.6).
• Heating chamber, inlet C1 and outlet C2: 3/8″ BSP on the 1.1/2″ and 1/2″ BSP on the 2″, 3″ and 4″ (MTEC-01/01, Table 17).
• Drains, instrument points, flush and quench follow Table 17 of the manual; instrument and sealing connections are made according to the application.

FB manufactures the FBE external gear series and the FBEI internal gear series in Cabreúva, Brazil, and the catalogues and manuals for both are in the site's technical library. Several FBE models are kept in stock, and the availability of each is given in the quotation. For high-viscosity oil, also compare the FBEI, whose standard series runs with a reducer at low speed (2026 FBEI catalogue, p.4). The MAN001-10 manual covers 10 models from 1″ to 4″, and the 2026 catalogue lists sizes from 1.1/2″ to 6″. For replacement, send the nameplate, complete code, available drawings and baseplate and connection dimensions; the FBE catalogue lists the spare components, from shafts and gears to bushings, seal and relief valve (p.4). For a new circuit, send the data below. The proposal identifies model, speed, materials, sealing, drive, accessories and included documentation.

• Oil: name, data sheet, ISO VG grade or viscosity with its measuring temperature.
• Temperatures: pumping, minimum at startup and maximum.
• Flow, discharge pressure and suction pressure or head.
• Contaminants: water, particles and suspended solids.
• Duty: continuous or batch, and the available heating.
• Installation: power supply, preferred drive and leakage restriction.