Svanehøj Deepwell Pump
Spare Parts Requests
DW gas cargo pumps · NMB booster pumps · DW Fuel pumps — shaft seal, deck bearing, coupling and pipe-stack items for gas carriers and gas-fuelled ships
The Svanehøj pumps behind gas carrier and fuel gas enquiries
Svanehøj was founded in 1928 in Aalborg, Denmark, by the marine engineer F. Dam. It developed its deepwell pumps at the beginning of the 1960s and moved to its present works at Svenstrup in 1966. When ITT completed its purchase of the business in January 2024, it described the programme as mainly deepwell gas cargo pumps, fuel and energy pumps and tank control systems. In a deepwell pump the electric motor stands outside the tank, a lineshaft runs down the pipe stack and the pump end sits low in the tank, so the first thing a request should state is the job the pump does: cargo, booster or fuel. Engine-room centrifugal pumps from the same group are presented by the maker under the Hamworthy Pumps name and are covered on the Hamworthy page.
DW Gas · DWG
Lineshaft-driven deepwell cargo pump that discharges through its own column, built for gas carriers from small fully pressurised ships to fully refrigerated VLGCs; the maker lists LPG, ammonia, ethane, ethylene, LNG and CO2 among the cargoes it handles without component changes. The maker's deck-level service schedule names the flexible coupling element, the bearing arrangement, the sealing liquid and the anti-rotation device; the double mechanical seal set comes in when the seal system shows a fault.
NMB Booster Pump
Raises discharge pressure when a fully refrigerated carrier offloads lighter cargoes, and is also built as an in-line vertical unit. The maker describes its shaft bearings and seals as easy to reach and its drive as a heavy-duty flexible coupling to the electric motor, so seal items, bearings and the coupling element are the parts to name.
DW Fuel Pump
The DW gas pump downsized for fuel gas supply: a multistage centrifugal pump in cryogenic stainless steel with the motor outside the fuel tank, offered for LNG and also for LPG, ethane, methanol and ammonia. The maker states that the pump can be retracted even with gas in the tank, which is what its foot valve system is for; name those parts first, then seal and bearing items.
CS Fuel Pump · HPP Triplex Pump Unit · HP NH3 Booster Pump
The CS Fuel Pump is the maker's all-electric submerged design for LNG fuel, with a self-cleaning filter; the HPP Triplex Pump Unit is a high-pressure piston pump unit for LNG; the HP NH3 Booster Pump for ammonia, also presented as the HP NH3 Fuel Pump, is hermetically sealed and has no mechanical shaft seals. Name the unit exactly, since the three are built on different principles.
DL · DW · CKL
Electrically driven deepwell cargo pumps for product and chemical tankers: an explosion-proof motor on deck, an oil-filled shaft column running in slide bearings held by O-rings, and a pump head carrying a double mechanical seal with a cofferdam between the seals, piped to deck for purging. The DL and CKL discharge through a dedicated pipe. The same designations are already indexed on this site under Hamworthy, the former parent.
Tank Control Systems
Gauging and safety equipment for gas tanks, including the LTD Gauge, LTD Sensor and LTD Marine Gauge. The business has been part of the Svanehøj group since 2021, when Wärtsilä sold it, and traces back to Whessoe, established in Calais in 1961. For a gauge, state the gauge type and the tank it serves rather than a pump designation.
Where a deepwell gas pump shows its wear, and where it does not
A deepwell pump is worked on from the deck down, and the maker's own service schedule follows that order. Its pre-docking programme for the DWG model sets planned work at five and at ten years of service and keeps all of it at deck level. Below deck it recommends no scheduled maintenance at all, because wear there depends strongly on how clean the cargo is: the pump is opened only when it runs with abnormal noise or vibration, loses performance, or is slow to build up discharge pressure. A parts list that follows the same logic is shorter and easier to justify.
Double mechanical seal and sealing oil
The gas pump has back-to-back mechanical shaft seals with a sealing oil chamber. A pressure booster loads the sealing oil from the cargo tank pressure and from a spring, so the seal chamber pressure stays above tank pressure without any adjustment by the crew. A seal chamber gauge that no longer reads above tank pressure, a falling level indicator, or oil in the leak oil collection chamber of the lower seal or at the leak oil outlet of the upper seal all point to the shaft seal arrangement. The sealing liquid itself is renewed at every scheduled service.
Flexible coupling element
The element between the motor and the pump shaft is renewed at each service point in the maker's schedule. It is a planned item rather than a repair, so it belongs on the same list as the seal work instead of turning into a second enquiry.
Main bearing arrangement
The bearing arrangement on deck is greased according to the manual at the first service point and overhauled at the second. The maker's pre-docking inspection uses vibration measurements, taken while the pump discharges, to judge the expected life of the bearings, so a vibration report is worth attaching to a bearing request.
Anti-rotation device
Its function is tested at each service, the drop-pins are checked for damage and the bearing housing cover for wear. Drop-pins are easy to leave off a dry-dock list, which is exactly why they should be named.
Pipe stack and multi-stage cylinder
Under the deck plate the pump has a bearing for each pipe-stack section, split couplings, an axially split housing, the multi-stage pump cylinder and an inducer. These are opened on evidence rather than by the calendar, so a request for them should carry the symptom and the cargo history, not a running-hour count.
Foot valve system
On the DW Fuel Pump the foot valve is kept shut by the fuel tank pressure, which is higher than the pressure in the pump caisson, and it is operated from outside the tank. Nitrogen presses the LNG out of the caisson through the foot valve, and once the valve is closed and the remaining gas vented, the pump can be withdrawn without emptying the tank. A foot valve that does not seat takes that option away, so its parts head any fuel pump list.
Svanehøj items that come up on dry-dock lists
Listed from the deck down, following the sectional drawing of the DW pump, so that each request line can carry the drawing item number from the ship's own manual. Where the manual words an item differently, the manual's wording wins.
- Double mechanical seal sets for the shaft seal arrangement
- Static seals, O-rings and joints of the seal housing
- Pressure booster and sealing oil chamber parts
- Seal chamber pressure gauge, level indicator and manometer arrangement items
- Flexible coupling elements and spacer coupling parts
- Main bearing arrangement bearings and bearing housing covers
- Anti-rotation device parts, drop-pins included
- Pipe-stack section bearings and split couplings
- Multi-stage pump cylinder internals, inducer parts and split housing joints
- DW Fuel Pump foot valve system parts
- NMB Booster Pump seals, bearings and coupling elements
- DL and CKL items: shaft seals, casing wear rings, column slide bearings with their O-rings, cofferdam purge connections
What to send from a Svanehøj pump
The owner's name on Svanehøj documents changed with the business. Svanehøj was bought by Hamworthy Pumps a few years after 1985, came to Wärtsilä together with Hamworthy in 2012, became an independent brand again in 2018 under Svanehøj Group A/S and has belonged to ITT Inc. since January 2024; in the Wärtsilä years the brand was written Wärtsilä Svanehøj. Send the plate exactly as it reads, then the items below.
- Plate photographed square-on, with the maker name exactly as it appears
- Full model designation: the family letters, the number after them and every suffix character
- Serial number and year of build
- Duty of the pump: cargo, booster or fuel, and for a cargo pump the tank number and pump position
- Cargoes or fuel the pump handles in service: LPG, ammonia, ethylene, LNG, CO2 or chemicals
- Pipe-stack length taken from the manual or arrangement drawing, not estimated
- Motor plate on deck, photographed on its own
- Item numbers from the sectional drawing in the pump manual
- Seal chamber pressure against cargo tank pressure when the fault was seen, and the symptom itself
- Latest condition assessment report or performance test sheet, if the ship holds one
Tools for this equipment: the mechanical seal material code for the seal faces, the flange identifier for the suction and discharge flanges, and the affinity laws calculator when a centrifugal pump runs on another supply frequency. Where the motor or the bearing arrangement on deck is regreased, the bearing grease quantity calculator gives the grease to add from the outside diameter D and the width B of the bearing, Gp = 0.005 x D x B, and the gun strokes for it; a quantity given in the manual comes first.
Supply route review for Svanehøj deepwell pumps
On a gas carrier a deepwell pump is part of the cargo system, so the route for each line follows from what that part does in the system.
Seals are a containment question
The shaft seal of a gas cargo pump is the barrier between the tank and the deck. Mechanical seal sets, the static seals of the seal housing and the foot valve parts of a fuel pump are quoted against the maker's reference, and where that reference cannot be confirmed for the serial in front of us, we say so in writing instead of offering a near match.
Deck-level consumables
Coupling elements, rolling bearings identified from their own markings and gaskets are a different case. For these a verified alternative can be put beside the OEM-route reference, within whatever the buyer's approval list allows for cargo-handling equipment.
One dry-dock scope
Where the ship holds a condition assessment report from a pre-docking inspection, the list is read against it as one scope: seal, coupling, bearing arrangement and anti-rotation items together rather than line by line.
Owner lineage checked
For a pump built under Hamworthy or Wärtsilä ownership, the documents that describe it are established before any part is named. The owner's name alone does not settle which drawing applies.
Below-deck work raised separately
Pipe-stack bearings, the pump cylinder and the inducer go on a separate line with the evidence that justifies lifting the pump, so the deck-level scope is not held up waiting for a decision on the pump end.
Svanehøj pump parts — recurring questions
The manual says Hamworthy or Wärtsilä Svanehøj. Is it the same maker?
For a Svanehøj deepwell pump, yes: the business simply had earlier owners. Svanehøj was acquired by Hamworthy Pumps a few years after 1985, passed to Wärtsilä with Hamworthy in 2012 and was sold with the rest of Wärtsilä's pumps business to Solix Group in 2018, when Svanehøj Group A/S was established as its parent; it has been part of ITT Inc. since January 2024. Send the plate as it reads together with the model designation: the designation and serial identify the pump, not the owner's name.
Which parts of a Svanehøj DW gas pump can be renewed without lifting it out of the tank?
The maker's pre-docking schedule for the DWG model lists the deck-level work: inspect and grease the electric motor, renew the flexible coupling element, grease and later overhaul the bearing arrangement, renew the sealing liquid, test the anti-rotation device and check its drop-pins and the bearing housing cover, and inspect the manometer arrangement. No below-deck work is scheduled; the maker advises it only for abnormal noise or vibration, lost performance or slow build-up of discharge pressure.
Seal chamber pressure on a Svanehøj cargo pump is falling. What goes on the request?
The sealing system is designed so that a pressure booster, loaded by tank pressure and a spring, keeps the seal chamber above cargo tank pressure. A falling seal chamber reading, a dropping oil level, or oil in the leak oil collection chamber of the lower seal or at the leak oil outlet of the upper seal points to the shaft seal arrangement. Name the double mechanical seal set, the static seals of the seal housing and fresh sealing liquid, and give the gauge readings, the tank pressure at the time and where the leak oil shows.
Can a Svanehøj DW Fuel Pump be serviced without emptying the fuel tank?
That is what its foot valve system is for. Fuel tank pressure holds the foot valve closed, the valve is operated from outside the tank, nitrogen presses the LNG out of the pump caisson, and once the valve is shut and the remaining gas vented the pump can be withdrawn for a full overhaul or a minor job. Confirm the foot valve parts before any other fuel pump item, because the whole procedure depends on them.
What should a Svanehøj pump RFQ contain?
The plate as it reads, the full model designation with every suffix character, the serial number and year of build, the duty with tank number and position, the cargoes or fuel handled, the pipe-stack length from the manual, the motor plate and the item numbers from the sectional drawing. Add the seal chamber readings or a description of the symptom, and the latest condition assessment report if there is one.
Is Vessel Core connected to Svanehøj?
No, and there is no agreement of any kind. Vessel Core holds no distribution, representation or partnership agreement with Svanehøj, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the plate and the last condition report.
List the model designation, serial number, duty, tank number and pump position, the items wanted and the port. Seal, coupling and deck bearing items are then read as one deck-level scope, and anything below deck is raised separately with the evidence that would justify opening it.
