What Is a Hydraulic Hose Assembly?

Hydraulic hoses are aliased as hydraulic oil pipes, hydraulic hoses, high-pressure hoses, hydraulic pipes, steel wire high-pressure pipes, steel wire braided hoses, steel wire wound hoses, and are generally divided into steel wire braided hydraulic hoses and steel wire wound hydraulic hoses. The hydraulic hose is mainly composed of a liquid-resistant inner rubber layer, a middle rubber layer, 2 or 4 or 6 steel wire winding reinforcement layers, and an outer rubber layer. The inner rubber layer has the function of subjecting the conveying medium to pressure and protecting the steel wire from erosion. The outer rubber layer protects the steel wire from damage, and the steel wire layer is a skeleton material for reinforcement.

First, the pipe

When the hydraulic hose joint is matched with other equipment, ensuring the seal between the hydraulic hose and the hose is the most critical step. Let's take a look at it below:

1.Hydraulic hose connector and hose connection

1. Ferrule joint connection-pressure range: 250-800 Bar; applicable steel tube size range: 4-42 mm; applicable materials: carbon steel and stainless steel.

The ferrule type pipe joint is composed of three parts: a connector body, a ferrule and a nut. When the ferrule and nut sleeve are inserted into the joint body on the steel pipe, when the nut is tightened, the outer side of the front end of the ferrule fits with the conical surface of the joint body, and the inner edge is evenly bite into the seamless steel pipe to form an effective seal.

Advantages: widely used and mature; relatively low cost parts; no special machine required.

Disadvantages: only suitable for pipe connections below 42mm; not suitable for thin-walled pipes; large installation space and torque are required during installation; not suitable for high safety requirements; cannot be used for strong vibration, shock and pulse Working conditions.

2. JIC37 degree joint connection-pressure range: 420 Bar (250 Bar, 100 Bar); applicable steel pipe size range: 6-38 mm; applicable materials: carbon steel, stainless steel, brass, copper alloy, etc.

JIC37 degree joint connection consists of three parts: joint body, bushing and nut. After the bushing and the nut are sleeved into the steel pipe, the flaring equipment is used to expand the pipe at the end of the steel pipe, and then the joint body and the nut are tightened, and the tapered surface is rigidly sealed and the O-ring is sealed.

Advantages: widely used and mature; wide range of applicable materials; simple and convenient installation; repeatable disassembly and assembly.

Disadvantages: only suitable for pipe connections below 38mm; low nominal pressure (except DNV standard); not suitable for thick-walled pipes; need to be formed at the end of the flaring equipment.

3. Tail end connection (Walform)-pressure range: 250-800 Bar; applicable steel tube size range: 4-42 mm; applicable materials: carbon steel, stainless steel, copper alloy, etc. ^[3]

Walform connections are an alternative to ferrule joints. After the mother sleeve is inserted into the steel pipe, it is automatically extruded at the end of the steel pipe with a molding device. After the seal ring is inserted, the joint body and the nut are tightened, and the joint body and the molding surface are rigidly sealed and the seal ring is sealed.

Advantages: low torque and safe installation; fast and simple production process; advanced technology without leakage; repeatable disassembly and assembly.

Disadvantages: Only suitable for pipe connections below 42mm; the end of the forming equipment needs to be formed.

4. Socket welding connection-pressure range: 420 Bar (only for small pipe diameter); applicable steel pipe size range: 6-150 mm; applicable materials: carbon steel and stainless steel.

The socket welding connection is to extend the pipeline into the valve body for welding. After molding, the shape is similar to the internal thread connection.

Advantages: Wide application; low price of parts; advanced technology without leakage; simple connection for low voltage systems.

Disadvantages: Skilled welding workers are needed; welding equipment, good ventilation environment and fire prevention measures are needed; special cleaning and anti-corrosion treatments are needed; it will cause environmental pollution.

5. Butt-welded connection-pressure range: 500 Bar (only for small pipe diameters); applicable steel pipe size range: 6-608 mm; applicable materials: carbon steel and stainless steel.

There are butt welding flange connections and butt welding head connections.

Advantages: Wide application; low price of parts; advanced technology without leakage; simple pipe-to-pipe connection.

Disadvantages: Skilled welding workers are needed; welding equipment, good ventilation environment and fire prevention measures are needed; special cleaning and anti-corrosion treatments are needed; environmental pollution will result. ^[1]