What are the Types of Medical Check Valve？

Medical Check Valve also knowns as Silicone Check Valve, Silicone One Way Valve, Rubber Non Return valve and Medical Diaphragm Flow Control Valve. Medical check valves used in medical devices are generally duckbill valves, umbrella valves, disk valves, v-ball valves, combination and bi-directional valves. There are many considering factors, such as material and processing way, when deciding which medical valve is suitable for application.

Material of medical check valve and its properties

Since 1960, silicone rubber has found widespread use in medical applications. Silicone rubber is an inorganic polymer formed by silicon, oxygen, carbon and hydrogen. To achieve its final characteristics, catalysts- platinum and peroxide are added during the curing process creating a chemical bond between the backbones called crosslinks. The cross-linked molecular chains enable them to combine the resilience and sealing force of an elastomer with the chemical inertness and thermal stability. Silicone rubber has become the ideal material for medical silicone valve because of its properties: good resistance to compression set, inert and stable compounds, flexibility over wide temperature ranges and a wide range of durometers.

Processing of duckbill check valve

Molding

Medical silicone valve is typically molded by three main methods: liquid injection molding, transfer molding or compression molding. During molding, temperature, pressure and time are three variables that must be controlled. The liquid injection molding process, often chosen for high-volume applications, employs lower pressures, higher temperatures and fast speed than the other molding methods. Therefore, liquid injection molding is one of the most common manufacturing processes for silicone rubber medical valve, own to its high levels of precision, high-volume production, decreasing labor processing cost, consistent quality and shorten vulcanizing curing time. Additional advantages include valve without burrs, flash-less tooling and reduced material waste.

The secondary cure

We had received complain about the odor of silicone rubber products. If medical silicone valve has odor, people are unavoidable to worry about its security, which is the biggest concern for medical grade valves. By nature, medical grade silicone is odorless, non-porous and tasteless, so odor molecules is hard to cling to silicone product.

Why does it happen? First of all, an aroma akin to vinegar on new made silicone products is normal. The smell of silicone products is produced during production processes-vulcanization process and curing process.

On the vulcanization process, additives are add into odorless silicone. It will have a chemical reaction. And some reactions may product with smell.

And on the curing process, mixed raw material will be put in a production machine in high temperature to be formed into its desired shape. Generally speaking, odor molecules evaporate at high temperatures. If odor molecules doesn’t evaporate completely, it will have strong odor.

In order to evaporating these smell molecules completely, the secondary cure process, that heat medical silicone valve in oven, is a good choice. Moreover the secondary cure can move away low molecular to achieve more stable products’ performance than without secondary cure.

All in all, it is necessary to secondary cure for medical silicone valves.

Major one way check valve types used in medical device applications

General-service valves

Pinch valves

Isolation valves

Proportional valves

Silicone check valve used in medical applications

There is a central requirement for gas and fluid handling in medical treatment today, seen in applications such as:

Dialysis

Dialysis is one of the most prominent applications, where general-service valves are used in both hemodialysis and peritoneal dialysis equipment.

Ventilation and respiratory therapy

Ventilators use proportional valves to control the mix of oxygen and air delivered to patients or to support more advanced breathing features. General-service valves are used in gas-handling and gas-delivery devices.

Surgical instruments

Surgical facilities depend on proportional and general-service valves. And pinch valves are used in surgical rinsing and suction, which demand the high-purity and hermetic separation characteristics.

Therapeutic devices

Therapeutic devices reply on robust proportional valves, which can meet ever-changing pressure and flow requirements within dynamic devices’ respective systems.

Our company

Xiamen Better Silicone is specialized in making silicone rubber compression molding & plastic injection molding & LSR injection molding and has rich experience in custom make silicone, rubber, plastic and liquid silicone rubber products by compression molding and injection molding over than 10 years.

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