Connections, straight hydraulic fittings  

Straight threaded connections for power hydraulics, connections with a seal 

Standardly, straight fittings have a male thread without a cone on one side (connection side), which is screwed into a block, in valve, distributor or another element, and a male thread with a cone on the other side for screwing in a hydraulic hose. stainless steel fittings ( acid-resistant )

What are straight fittings?

Straight fittings are fastening elements used in power hydraulics that allow for safe and tight connection of hydraulic lines with various system components, such as valve bodies, pumps, or distributors. Thanks to their simple design and high-quality workmanship, these fittings are a reliable choice in diverse industrial and mobile applications. Interestingly, modern hydraulic fittings use cones, so these elements can be used as a connection (for connecting) or as a connector for joining hydraulic lines. 

Types of straight fittings used 

Fittings can come in several versions: 

Connection with ED seal	Connector / Fitting	Fitting (old type)
+ does not require additional sealing	- requires metal-rubber washer + can be used as a connector	- requires metal-rubber washer

Straight fittings with ED seal

The latest and most popular type of straight fittings available on the market. This type has a special undercut and a square-section seal; just tighten it with a wrench to achieve a perfect tight connection. Fittings with an O-ring seal (regular O-ring) have appeared on the market, but they do not provide as good a seal as square-section ED seals. For this fitting, we do not need to use any additional sealing. 

Straight fitting GE-R-ED

The GE-R-ED straight fitting is a key element of power hydraulic systems, connecting an end with a male BSPP inch thread to an EO end with a 24° cone. Thanks to the factory-applied Eolastic ED soft seal (ISO 1179), this connector guarantees 100% tightness and eliminates the risk of working fluid leaks even under high pressure and strong vibrations.

Depending on installation requirements, GE-R-ED connectors are available in three pressure classes: very light series (LL), light (L), and heavy (S). Standard execution is corrosion-resistant galvanized steel (CF suffix), but stainless steel (71) and brass (MS) versions are also offered. Products are delivered in OMD configuration (body without nut and ring), allowing for optimal adjustment to the pipeline being built. Choose proven GE-R-ED fittings and ensure trouble-free operation of your machinery!

Connectors / fittings 

Fittings marked with this type of name inform us that these elements have a dual application: 1) they can be used as regular fittings (it is necessary to use a metal-rubber or copper washer). The second application is as a standard connector (this element has a thread and a cone on both sides), e.g., for connecting hydraulic hoses. Elements of this type usually have a larger hexagon (larger than standard connectors), allowing the use of sealing washers, metal-rubber, or copper ones. 

Fittings 

Standard fittings. Old-type fittings with no cone (no seal) on one side and a male thread with a cone on the other. On the connection side, it is necessary to use a metal-rubber washer or a copper seal. Formerly, all fittings were produced in this type. This type of straight fittings is produced according to the POLISH STANDARD and is known as: STRAIGHT FITTING BODY (PN-65/M-73140). It is possible to order a set according to PN-65 M-73126: Version A – Straight fitting body + cutting ring + nut or Version B – Straight fitting body + spherical end + nut. 

Where are straight threaded connections used? 

Straight fittings are commonly used in hydraulic installations, providing durability and tightness in demanding environments. Fittings are primarily used in the power hydraulics industry. Connections are also used in industries such as: Heavy industry: Hydraulic systems in construction and industrial machinery, Chemical industry: Pipelines and transmission installations for aggressive media, Transport: Hydraulic systems of trucks and agricultural machinery. Energy: Oil and water installations in power plants. 

Technical parameters of straight connections 

• Material: Carbon steel, stainless steel AISI 316
• Protective coating: Standard galvanization, Zn-Ni,
• Thread types: metric, BSP, UNF, ORFS
• Pressure range: up to 630 bar.
• Standards: DIN 2353, ISO 8434-1, SAE J514.

Different versions of hydraulic connections 

Straight fittings are available in many varieties:

• With ED seal: Elastomeric O-rings for better tightness.
• With metal sealing edge: For high-pressure and precision applications.
• Reducing versions: Allow the connection of lines with different diameters and different threads