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Hydraulic Oil Filters: Suction and Return Filters with Elements
Suction filters from 25 to 750 l/min, tank-top and in-line return filters, complete filter assemblies and replacement filter elements.
The great majority of hydraulic faults come down to a single cause: dirt in the oil. Metal particles shed by wear, dust introduced during assembly and rubber crumbs from seals circulate through the micron-scale clearances of pump and valves. The filter is the only element that breaks this cycle, and although it is one of the cheapest parts in the system, neglecting it produces the most expensive damage.
A filter occupies one of three positions in the circuit. The suction filter works at the pump inlet, submerged in the tank; it is a coarse filter and protects the pump from large particles. Its rating is given in l/min (25, 45, 65, 90, 125, 180, 225, 300, 500, 750) and must not be selected below the pump flow. Its dimensions are listed as length, diameter and thread (L:160 D:61 A:1, for instance), because it has to fit inside the tank.
The return filter comes into play as oil flows back to the tank. It is a fine filter, and since all the circulating oil passes through it, it does the real cleaning. Tank-top versions simplify mounting. The pressure line filter is used after the pump, immediately ahead of a sensitive valve that needs protecting; it gives the finest filtration, but its housing is built to withstand full system pressure.
The second axis of selection is pore size, given in microns and visible in the product code (C25 = 25 micron). A finer filter delivers cleaner oil but clogs sooner and causes more pressure drop. Typical values are 100–125 micron on suction and 10–25 micron on return.
Filters are sold either as complete housings or as elements alone. Routine maintenance normally changes the element while the housing stays in place. A clogged suction filter creates a vacuum at the pump inlet, bubbles form in the oil and the pump cavitates — this is the most common reason for a pump that runs with a growling noise. Read this page together with the fault notes on the «Hydraulic Pumps» page.
Brands and series
Ferro 13 products
Series pages are in Turkish; product codes are the same in every language.
Other products (brand not specified)
21 products in our price lists with no brand or no code stated, sorted by name (in Turkish). Pages: 1.
Brands and standards in stock
Manufacturer part numbers
These products are searched for in the field by the manufacturer's part number, not by our stock code. The code follows this pattern: TİP + HORTUM ÖLÇÜSÜ + DİŞ — for example ZFB10-FE. Every code in the lists below can be supplied; some are held in stock ready to ship.
Vakum filtresi
Vacuum filter. Every code listed can be supplied. The manufacturer's catalogue lists 10 codes in this series; all can be supplied.
10 codes
ZFB10-FEZFP30-FEZFB15/20-FEZFP100-FEZFB25-FEZFP120-FEZFB40-FEZFP40ZFP100ZFP120Filtre
Filter. Every code listed can be supplied. The manufacturer's catalogue lists 5 codes in this series; all can be supplied.
5 codes
OFF-3OFF-4OFF-7OFF-5OFF-6The codes listed are the manufacturer's own part numbers. For sizes not held in stock, ask for the lead time — supply is quick because we carry the series. Prices are given on quotation.
Frequently asked questions
Which matters more, the suction filter or the return filter?
They do different jobs. The suction filter protects the pump from large particles and is coarse by necessity — it cannot be fine, because a pressure drop at the pump inlet causes cavitation. The real cleaning is done by the return filter: all the oil circulating in the system passes through it on its way back to tank. A healthy circuit has both.
How is filter flow rating selected?
The filter rating must not be below the pump flow. On the suction side this rule is especially strict: an undersized filter creates a vacuum at the pump inlet and leads to cavitation. On the return side, allow for the surge of flow produced as a cylinder retracts and choose one size up.
What does the micron value mean?
It is the size of the smallest particle the filter will stop; it appears in the code as C25, meaning 25 micron. A smaller number means finer filtration. Typical values are 100–125 micron on suction and 10–25 micron on return. A filter finer than needed clogs quickly and opens its bypass valve, leaving the system running unfiltered.
How often should a filter be changed?
Go by the contamination indicator rather than by elapsed time. Where an indicator is fitted, change the element when the needle enters the red zone. Without one, make the first change within the first 50 hours after commissioning — that element collects the assembly debris — and thereafter typically every 500 to 1000 hours. The filter must always be changed with the oil.
Should I buy a complete filter or just the element?
If the housing is sound the element alone is enough, and that is what routine maintenance changes. A complete filter is bought for a new installation, for a cracked housing, or when moving to a different flow. When ordering an element, state both the housing type and the micron value — elements of the same size are produced in several pore ratings.
The pump growls — could the filter be involved?
Very likely. A clogged suction filter creates a vacuum at the pump inlet; vapour bubbles form in the oil and collapse in the pressure zone. This phenomenon, cavitation, produces the characteristic growl and eats the pump from the inside. The first places to check are the suction filter and the oil level.
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