Pumps, Compressors, Turbines, and Mechanical Components for Fluid Movement and Power Generation
Rotating equipment is the mechanical heart of every oil and gas facility. Pumps move crude oil from wells to processing. Compressors push gas through pipelines. Turbines generate power and drive critical machinery. When a rotating machine fails, production stops—sometimes for days or weeks. The right spare parts, sourced quickly and correctly, are the difference between a brief shutdown and a costly outage.
Hoger supplies OEM, equivalent aftermarket, and reconditioned rotating equipment spares from qualified global manufacturers. Every component comes with full material certification, dimensional inspection, and OEM cross-reference verification.
Rotating Equipment
Our Rotating Equipment Categories at a Glance
Category
Primary Function
Key Products
Centrifugal Pumps
High-flow, continuous-duty liquid transfer
API 610, ANSI B73.1, ISO 5199 pump spares and complete units
Centrifugal pumps are the most common pump type in oil and gas. They use a rotating impeller to impart kinetic energy to the fluid, converting it to pressure in the volute or diffuser. They excel at high flow rates with steady discharge pressure.
Pump Types by Standard
Standard
Type
Description
Application
API 610
Overhung (OH1, OH2, OH3)
Impeller cantilevered from bearing housing. Foot or centerline mounted
Refinery process, hydrocarbon transfer, moderate head
API 610
Between-Bearings (BB1, BB2, BB3, BB4, BB5)
Impeller supported between bearings. Single or multi-stage
High pressure, boiler feedwater, pipeline, water injection
API 610
Vertical Suspended (VS1-VS7)
Pump submerged in sump or vessel
Condensate extraction, sump drainage, cooling water
ANSI B73.1
End-Suction, Foot-Mounted
Standardized dimensions for interchangeability between brands
Throttle leakage between high and low pressure zones
Every 2-5 years (API clearance limits)
Shaft
Transmits torque from driver
Overhaul or as inspected
Shaft Sleeve
Protects shaft at seal and bearing areas
Every seal replacement
Bearing (Radial / Journal)
Supports rotating assembly
Per vibration monitoring or 3-5 years
Bearing (Thrust)
Resists axial load
Per vibration monitoring or 3-5 years
Mechanical Seal
Prevents leakage at shaft penetration
2-5 years (process dependent)
Bushings / Throat Bushing
Stabilizes shaft, limits solids ingress
Overhaul
Gaskets & O-Rings
Static sealing
Every disassembly
Coupling
Transmits torque from driver
Per inspection or 5-10 years
POSITIVE DISPLACEMENT PUMPS
Positive Displacement (PD) Pumps
High-Pressure, Viscous, and Metered Liquid Transfer
Positive displacement pumps trap a fixed volume of fluid and displace it mechanically. Unlike centrifugals, they deliver near-constant flow regardless of discharge pressure—making them ideal for high-viscosity fluids, high-pressure injection, and precision metering.
PD Pump Types
Type
Principle
Best For
Reciprocating (Piston / Plunger)
Piston or plunger reciprocates in cylinder. Check valves control flow direction
Highest pressure. Water injection, chemical injection, mud pumps
Gear (External)
Two meshing gears trap fluid between teeth and casing
Viscous fluids. Lube oil, fuel oil, bitumen
Gear (Internal)
Internal gear meshes with external gear. Crescent seal
Viscous, shear-sensitive. Asphalt, polymers
Screw (Twin / Triple)
Intermeshing screws convey fluid axially
High flow PD. Crude oil transfer, multiphase, pipeline
Screw (Single / Progressive Cavity)
Rotor turns eccentrically in elastomeric stator
Slurries, solids-laden, viscous, high sand (oilfield PC pumps)
Diaphragm (Air-Operated – AODD)
Compressed air drives alternating diaphragms
Portable, solids handling, hazardous area, chemical transfer
Diaphragm (Metering / Dosing)
Positive displacement with adjustable stroke
Precision chemical injection. Methanol, corrosion inhibitor, demulsifier
Vane
Sliding vanes in rotor slot sweep fluid
Clean, low-viscosity fluids. LPG, solvents, fuel
Lobe
Two rotating lobes mesh without contact. External timing gears
Food-grade, shear-sensitive, polymers
Peristaltic (Hose Pump)
Roller squeezes hose, pushing fluid
Metering, abrasive slurries, shear-sensitive, no seals
Key Spare Parts (Reciprocating Pumps)
Component
Function
Piston / Plunger
Displaces fluid. Coated (ceramic, tungsten carbide) for abrasion
Piston Rings / Rider Rings
Seal between piston and cylinder. Wear items
Packing / Stuffing Box Packing
Seals around reciprocating rod
Valves (Suction & Discharge)
One-way flow control. Spring-loaded poppet, ball, or plate
Valve Seats & Springs
Sealing surface and return mechanism
Crankshaft Bearings
Support crankshaft in frame
Crosshead & Guide
Converts rotary to linear motion
Connecting Rod
Links crankshaft to crosshead
Key Spare Parts (Gear & Screw Pumps)
Component
Function
Gears / Screws
Pumping elements. Matched set
Bushings / Bearings
Support rotors
Timing Gears
Synchronize rotors (external gear and screw pumps)
Mechanical Seals
Shaft sealing
Casing / Liners
Contain fluid. Replaceable in abrasive service
CENTRIFUGAL COMPRESSORS
Centrifugal Compressors
High-Volume, Continuous-Duty Gas Compression
Centrifugal compressors use high-speed impellers to accelerate gas, then decelerate it in diffusers to convert velocity into pressure. They are the backbone of gas processing, LNG, and pipeline transportation. A single compressor can move hundreds of millions of standard cubic feet per day.
Compressor Configurations
Configuration
Casing Type
Stages
Application
Single-Stage Overhung
Radially split
1
Low pressure boost, recycle, vapor recovery
Multi-Stage Horizontally Split
Axially split
Up to 10+
Pipeline, gas processing, moderate pressure
Multi-Stage Barrel (Radially Split)
Barrel / Double casing
Up to 10+
High pressure. Gas injection, LNG, synthesis gas
Pipeline Compressor
Axially split
1-2
Pipeline transmission. High flow, low ratio
Integrally Geared
Multiple pinions
Multi-stage, intercooled
Plant air, nitrogen, CO2 compression
Key Spare Parts
Component
Function
Replacement Trigger
Impeller (Open, Semi-Open, Closed)
Accelerates gas
Erosion, fouling, overspeed damage
Diaphragm / Diffuser
Converts velocity to pressure. Stationary
Erosion, fouling
Labyrinth Seals (Eye, Interstage, Balance Drum)
Minimize internal gas recirculation
Clearance increase from wear. Monitored by performance degradation
Journal Bearings (Tilting Pad, Sleeve)
Support rotor radially
Vibration increase, Babbit wear
Thrust Bearing (Tilting Pad)
Resist axial thrust
Axial displacement increase
Dry Gas Seal (Primary, Secondary, Barrier)
Prevent process gas leakage at shaft
5-10 years typical. Leakage rate monitoring
Rotor Assembly
Shaft + impellers. Balanced
Overhaul, overspeed event
O-Rings & Gaskets
Static sealing
Every disassembly
Balance Drum / Piston
Compensates axial thrust
Clearance degradation
Coupling (Flexible Disc or Diaphragm)
Transmits torque from driver
Per inspection
Dry Gas Seals (DGS)
The critical shaft sealing technology for centrifugal compressors. A thin gas film (3-10 microns) separates rotating and stationary seal faces. Zero process gas leakage to atmosphere when connected to primary vent or flare.
Seal Gas System Components:
Seal Gas Filter (Duplex): Removes particulates >1-3 micron
Seal Gas Heater: Prevents condensation across seal faces
Primary Vent: To flare or safe location. Monitored for leakage rate
Secondary Vent: To safe location. Monitored for primary seal failure
Separation Gas (N2 or Air): Buffer between bearing oil and seal
RECIPROCATING COMPRESSORS
Reciprocating Compressors
High-Pressure, Low-to-Medium Flow Gas Compression
Reciprocating compressors use a piston moving within a cylinder to compress gas. Check valves control inlet and discharge. They are the technology of choice for high-pressure ratio applications where centrifugals are impractical—gas lift, gas gathering, hydrogen compression, and CNG.
Compressor Configurations
Configuration
Cylinder Arrangement
Stages
Horizontal
Cylinders on one or both sides of frame. Most common for large machines
Up to 6+
Vertical / V-Type
Cylinders arranged in V-shape. Compact
1-4
Balanced Opposed
Cylinders on both sides of frame. 180° opposed. Eliminates unbalanced forces
Multi-stage, large
Labyrinth Piston
Non-contact piston. No lubrication. For oxygen or ultra-clean service
Single stage
Key Spare Parts
Component
Function
Replacement Frequency
Compressor Valves (Suction & Discharge)
One-way flow control. Most common wear item
8,000 – 16,000 hours typical
Valve Seats & Springs
Sealing and return
With valve replacement
Piston Rings
Seal between piston and cylinder
8,000 – 16,000 hours
Rider Bands (Support Rings)
Support piston weight, prevent cylinder contact
With piston rings
Packing Rings (Pressure Packing)
Seal around piston rod at cylinder penetration
8,000 – 20,000 hours. Leakage-dependent
Piston Rod
Transmits force to piston. Precision ground/hard-coated
Overhaul or as inspected. NDE for cracks
Cylinder Liner
Replaceable cylinder bore for wear protection
Overhaul. Bored or replaced on wear
Crosshead & Crosshead Pin
Rotary-to-linear conversion. Bearing surfaces
Overhaul
Connecting Rod
Link between crankshaft and crosshead
Overhaul
Main Bearings
Support crankshaft
Condition-based. 5-10 years
Wipers & Oil Scrapers
Prevent oil migration between frame and cylinder
With packing replacement
Distance Piece Packing
Secondary seal. Isolates process from crankcase
Per condition
Compressor Valve Types
Type
Description
Best For
Plate Valve
Flat metal or plastic plate seats on flat seat
General. Most common
Ring Valve
Concentric metal rings. Good for high flow
High flow, moderate pressure
Poppet Valve
Individual poppets with springs. Each operates independently
Prime Movers for Power Generation and Mechanical Drive
Turbines convert thermal energy into rotational mechanical energy. Gas turbines burn fuel gas to produce hot combustion gases that expand through turbine blades. Steam turbines use high-pressure steam from boilers or HRSGs. Together, they drive generators, compressors, and pumps across the oil and gas industry.
Gas Turbine Types
Type
Output Range
Application
Microturbine
25 – 500 kW
Remote power, flare gas utilization
Industrial (Heavy-Duty)
1 – 500 MW
Power generation, LNG liquefaction, large compressors
Aeroderivative
10 – 100 MW
Offshore platforms, pipeline compression, fast start
Multi-Shaft
Variable
Mechanical drive (compressor, pump)
Single-Shaft
Variable
Power generation
Steam Turbine Types
Type
Description
Application
Condensing
Exhausts to vacuum (condenser). Maximum efficiency
Power generation
Back-Pressure
Exhausts at positive pressure for process use
Combined heat and power, process steam
Extraction
Steam extracted at intermediate pressure for process
Refinery steam systems
Induction
Low-pressure steam admitted to intermediate stage
Waste heat recovery
Key Spare Parts (Gas & Steam Turbines)
Component
Function
Replacement Trigger
Turbine Blades / Buckets (Rotating)
Extract energy from gas/steam. Precision forged/cast
Erosion, creep, foreign object damage
Nozzles / Vanes (Stationary)
Direct flow onto rotating blades. Stationary
Erosion, fouling, coating degradation
Journal Bearings (Tilting Pad)
Support rotor
Vibration, Babbit wear
Thrust Bearing
Axial positioning
Axial displacement
Labyrinth / Brush Seals
Minimize internal leakage
Clearance degradation
Combustion Liner / Transition Piece
Contains combustion (gas turbine)
Thermal cracking, distortion
Fuel Nozzle
Atomizes fuel into combustor (gas turbine)
Clogging, coking, erosion
Spark Plug / Ignitor
Ignites fuel-air mixture (gas turbine)
Routine replacement
Flame Detector
Confirms flame presence
Routine calibration/replacement
Lube Oil Pump & Motor
Supplies bearing oil
Condition-based
Lube Oil Filter (Duplex)
Clean oil
Differential pressure trigger
Trip & Throttle Valve
Emergency steam shutoff (steam turbine)
Routine testing/replacement
Governor / Control Valve
Controls steam or fuel flow
Routine maintenance
OEM Manufacturers We Support
Manufacturer
Specialty
GE (General Electric)
Heavy-duty & aeroderivative gas turbines, steam turbines
Siemens Energy
Industrial gas turbines, steam turbines, compressors
Solar Turbines
Mid-range gas turbines for mechanical drive and generation
Mitsubishi Heavy Industries (MHI)
Large-frame gas and steam turbines
Baker Hughes (Nuovo Pignone)
Gas turbines and compressors for oil and gas
MAN Energy Solutions
Industrial gas and steam turbines
Dresser-Rand (Siemens)
Steam turbines and reciprocating compressors
Elliott Group
Steam turbines and centrifugal compressors
Howden
Screw compressors, fans, rotary equipment
MECHANICAL SEALS
Mechanical Seals
Precision Shaft Sealing for Pumps, Compressors, and Mixers
Mechanical seals are the primary defense against process fluid leakage at the point where a rotating shaft exits a stationary housing. A correctly specified, installed, and operated mechanical seal eliminates visible leakage and meets environmental and safety requirements. Seals are manufactured to API 682 for refinery and chemical service, or to OEM specifications for specific machines.
Seal Types (API 682 Classification)
Type
Arrangement
Description
Application
Single Seal (Arrangement 1)
One seal. Sealed by process fluid or external flush
Simplest, lowest cost
Non-hazardous, non-flashing fluids. Clean service
Double Seal (Arrangement 3)
Two seals back-to-back or face-to-face. Barrier fluid between at pressure > process
Barrier fluid circulates. Zero process leakage to atmosphere
Hazardous, toxic, or high-value fluids
Tandem Seal (Arrangement 2)
Two seals in series. Buffer fluid between at pressure < process
Inner seal takes full pressure. Outer seal is backup
Flashing, hazardous fluids. Monitored leakage
Unbalanced
Seal face closing force increases with pressure
Simpler design. Older technology
Low pressure (<20 bar)
Balanced
Seal face closing force is proportionally reduced
Lower face pressure = lower wear and heat
High pressure (>20 bar). Modern standard
Pusher Seal
Dynamic secondary seal (O-ring) slides along shaft
Compensates for wear and misalignment
General service
Non-Pusher (Bellows) Seal
Metal or PTFE bellows provides flexibility. No dynamic secondary seal
No shaft fretting. Self-cleaning
High temperature, dirty or coking fluids
Key Seal Components
Component
Material Options
Function
Primary Ring (Stationary Face)
Carbon, Silicon Carbide, Tungsten Carbide
Stationary sealing face
Mating Ring (Rotating Face)
Silicon Carbide, Tungsten Carbide
Rotates with shaft. Forms seal gap with primary ring
Static sealing between seal components and shaft/housing
Spring / Bellows
316 SS, Hastelloy C276, Inconel 718, Elgiloy
Maintains face contact during wear, misalignment, and thermal expansion
Drive Mechanism
Set screws, drive pins, drive collars
Transmits torque from shaft to rotating face
Sleeve / Shaft Sleeve
316 SS, Duplex, Inconel
Protects shaft. Seal mounting surface
API 682 Seal Categories
Category
Temperature
Pressure
Application
Category 1
-40°C to +260°C
<22 bar
Standard refinery. Most common
Category 2
-40°C to +400°C
<42 bar
Higher temperature, pressure, and speed
Category 3
-40°C to +400°C
<42 bar
Tested to stricter qualification. Critical/unspared pumps
API 682 Seal Types (Material Sets)
Type
Metal Parts
Seal Faces
Secondary Seals
Application
Type A
316 SS
Carbon vs. SiC
FKM (Viton)
Water, light hydrocarbons, moderate temp
Type B
316 SS + Hard-faced
Carbon vs. SiC
FFKM (Kalrez)
Aromatics, acids, higher temp
Type C
Inconel 718
SiC vs. SiC
Graphite / PTFE
High temperature, coking, thermal cycling
BEARINGS
Bearings
Rotating Shaft Support and Load Transfer
Bearings support rotating shafts, transferring radial and axial loads while minimizing friction and wear. They are among the most replaced components in rotating equipment. Correct specification of bearing type, clearance, material, and lubrication is critical to equipment reliability.
Bearing Types
Type
Load Direction
Description
Application
Deep Groove Ball
Radial + Moderate Axial
Most common. Simple, versatile
Small-to-medium pumps, motors, fans
Angular Contact Ball
Radial + Axial (one direction)
Higher axial capacity than deep groove. Paired for bidirectional
Pumps, compressors, gearboxes
Self-Aligning Ball
Radial
Two rows of balls. Compensates for shaft misalignment
Fans, blowers
Cylindrical Roller
Radial (high)
Line contact for higher radial load
Large pumps, gearboxes, compressors
Spherical Roller
Radial (very high) + Axial
Barrel-shaped rollers. Self-aligning. High load capacity
Heavy-duty, crushers, conveyors
Tapered Roller
Radial + Axial (one direction)
Conical rollers. High combined load. Paired
Gearboxes, wheel bearings
Needle Roller
Radial
Small diameter rollers. Compact radial space
Connecting rod bearings, transmissions
Thrust Ball
Axial only
Flat washers with ball cage. Pure thrust
Vertical pump thrust, low load
Tilting Pad Thrust
Axial (very high)
Multiple pivoting pads. Hydrodynamic oil film
Compressors, turbines, high-speed pumps
Tilting Pad Journal
Radial (high) + Stability
Multiple pivoting pads around shaft. Excellent stability
High-speed compressors, turbines
Sleeve / Journal (Plain)
Radial
Simple cylindrical bore. Oil film or grease
Slow speed, moderate load, pumps, fans
Hydrodynamic Journal
Radial
Wedge-shaped oil film lifts shaft
Turbines, large compressors, generators
Magnetic
Radial + Axial
Electromagnetic levitation. No contact, no oil
Ultra-high speed, vacuum, no contamination
Bearing Selection Factors
Factor
Consideration
Rotational Speed (RPM)
High speed → Tilting pad, angular contact, precision ball
Load (Magnitude & Direction)
High radial → Roller. High axial → Thrust, angular contact
Tilting pad thrust and journal bearings. Large machines
Michell
Tilting pad bearings
Waukesha
Hydrodynamic journal and thrust bearings
COUPLINGS & ALIGNMENT
Couplings & Alignment
Shaft-to-Shaft Power Transmission and Misalignment Accommodation
Couplings connect the driving shaft (motor, turbine, engine) to the driven shaft (pump, compressor, generator). They transmit torque while accommodating unavoidable misalignment—radial, axial, and angular. A failed coupling can cause catastrophic machine damage.
Coupling Types
Type
Flexibility
Max Torque
Best For
Flexible Disc / Diaphragm
High
Very High
High-speed, high-torque. Compressors, turbines. API 671
Gear Coupling
High
Very High
High torque, moderate speed. Legacy. Being replaced by disc
Grid Coupling
Moderate
High
Pumps, fans, general industrial
Elastomeric (Jaw, Tire, Pin & Bush)
High
Low-Moderate
Small-to-medium pumps, fans, conveyors
Disc Pack Coupling
High
Very High
API 610 pumps, compressors
Flexible Element (Membrane)
High
High
High-speed. No lubrication
Fluid Coupling
Variable
Variable
Conveyors. Soft start, speed control
Rigid (Flanged, Sleeve)
None
High
Close-coupled shafts. No misalignment tolerated
Universal Joint (Hooke’s Joint)
Angular only
Moderate
Large angular misalignment. Drive shafts
Torsionally Soft Coupling
High (dampens)
Variable
Reciprocating compressors and engines. Dampens torque fluctuations
Coupling Selection Factors
Factor
Consideration
Torque (Continuous & Peak)
Must exceed driver maximum torque including service factor
Speed (RPM)
Affects balance grade and coupling type
Shaft Sizes
Determines hub bore capacity
Misalignment Capacity
Radial (parallel), axial (end float), angular
Service Factor
Multiplier for driver type (electric motor 1.0, engine 1.5-2.0, turbine 1.25-1.5)
Lubrication
Gear couplings require grease. Disc/diaphragm are dry
ATEX / Hazardous Area
Spark-resistant requirements for Zone 1/2
Shaft Alignment
Method
Accuracy
Application
Straight Edge & Feeler Gauge
Low
Small, non-critical machines
Dial Indicator (Rim & Face)
Moderate-High
Traditional method. Skill-dependent
Laser Alignment
Very High
Modern standard. Faster, more accurate, documented
LUBRICATION SYSTEMS
Lubrication Systems
Oil Supply, Conditioning, and Monitoring for Rotating Equipment
Lubrication systems supply clean, cooled oil to bearings, seals, gearboxes, and control systems. For critical, unspared machinery—turbines, large compressors, high-energy pumps—the lube oil system is as important as the machine itself. A lube oil failure can destroy bearings and seals in seconds.
