The difference between the Delivery Hose and the Suction and discharge Hose

There are fundamental design and functional differences between the "delivery hose" and the "suction and discharge hose" categories. These differences directly determine their application scenarios, performance, and safety. As an enterprise that has been deeply involved in the rubber hose export industry for many years, we hope that through this detailed technical analysis, we can help global customers make more accurate, safer, and more economical choices.

I. Essential Differences

Delivery Hose: One-way pressure-driven system

Core principle: The piping for conveying is a passive transmission channel. It relies on the positive pressure generated by an external pump or pressure source to "push" the medium from the high-pressure end to the low-pressure end. The piping itself does not generate power; it merely serves as a conduit and bears the internal pressure.

Suction and discharge hose: Bidirectional pressure circulation system

Core principle: The suction and discharge hose is a part o     f an active pressure circulation system. It first needs to create negative pressure (vacuum) at the inlet end of the pump to "suck in" the medium into the hose, and then withstand positive pressure at the outlet end of the pump to "discharge" the medium. A complete suction and discharge process involves a complete cycle of pressure from negative to positive.

II. Structural Design Features

Structural characteristics of the conveying hose:

The reinforcement layer is designed to withstand internal pressure primarily.

Usually, wire-reinforced layer is used.

The inner liner is smooth to reduce flow resistance.

Pressure resistance is its key performance indicator.

Structural features of the suction and discharge hoses:

The reinforcing layer needs to simultaneously resist negative pressure collapse and positive pressure expansion.

Spiral steel wire + wire reinforcement layer is commonly used.

The Hosewall is usually thicker to maintain rigidity.

Resisting collapse is the primary consideration.

III. Differences in Inner Seal Materials

Conveying hose：

Key points: Compatibility with the medium, low permeability, low friction coefficient.

For example: NBR (nitrile butadiene rubber) for transporting fuel, FKM (fluororubber) or EPDM (terpolymer ethylene propylene diene monomer) for transporting chemicals, platinum-sulfided silicone rubber or EPDM for transporting food.

Suction and discharge hoses:

Focus: Besides medium compatibility, resistance to flex fatigue and high elastic modulus are more critical.

As the Hosewall undergoes periodic deformation during suction, the inner rubber must be able to withstand repeated "micro-collapse-recovery" cycles without cracking.

Usually, high-strength and high-elasticity rubber compounds are used, and anti-static agents (used to prevent sparks when transporting flammable media) may be added.

IV. Application Scenario Comparison

Special scenarios for Conveying hose:

Fixed pipelines in factories: Pipes connecting reaction vessels, storage tanks and packaging machines.

Hydraulic systems: Hydraulic oil pipes for construction machinery (extremely high pressure, pure positive pressure).

Compressed air transportation: Air supply for pneumatic tools.

Garden watering: Household tap water flexible hoses.

Special scenarios for suction and discharge hoses:

Oil tanker loading and unloading: Suction oil from underground storage tanks to the tanker, and then discharge to the target oil depot.

Waste discharge and dredging: Suction trucks, river dredging vessels.

Suction grain machines: In agriculture, extract grains from grain silos.

Firefighting water pumping: Pump water from lakes and pools to extinguish fires.

V. Purchase Guide

When choosing a conveying hose, please consider:

• Work pressure range

• Chemical properties of the transmission medium

• Environmental temperature conditions

• Required bending radius

• Type of connector and compatibility

When choosing the suction and discharge hoses, please note:

• The required vacuum level (negative pressure)

• The range of allowable positive pressure at the same time

• The wear resistance of the medium

• The bending frequency during use

• Whether it needs to be used in a relaxed state

VI. Common Misconceptions and Precautions

• Do not use interchangeably: The suction and discharge hose can be used for transportation, but the transportation hose is not suitable for vacuum suction and discharge scenarios.

• Pressure level misunderstanding: High-pressure transportation hoses may collapse easily under negative pressure.

• Life expectancy difference: Due to more demanding working conditions, suction and discharge hoses usually require more frequent inspection and replacement.

• Connection selection: Suction and discharge hoses require more stringent sealing connections to prevent air from entering.