Vacuum Pressure Impregnation for Wood Treatment

NASH liquid ring vacuum pumps offer several advantages to wood treatment applications. They have no trouble handling the saturated air with entrained liquid. They are also very tolerant of the resinous components and vapors of preservative chemicals.

Tolerant, Reliable Vacuum Solutions

Wood preservation impregnates the wood to stabilize its dimensions, increase its resistance to water and chemicals and reduce cracking.

The structure of wood is similar to a sponge, with cell cavities and cell walls, which represent the actual wood. Wood treatment coats these walls with preservatives to protect it from decay caused by wood-destroying fungi and insects. 

The preservative penetrates deep into the wood with pressure and vacuum. The vacuum removes the air from the cavities to create space for the preservation solution. This solution is forced deep into the wood under high pressure.

NASH Liquid Ring Vacuum Pump Basic Process Procedures

Basic Process

Wood treatment resists wood rotting and infestation due to soil or water, fungi, insects and other elements. This process is widely employed in damp and excessively humid areas. To obtain maximum penetration of preservatives, vacuum is used to impregnate the wood.

While process requirements vary in the desired vacuum and capacity, the basic procedures are similar. These procedures consist of the following processes:

  • Initial Vacuum - Once the wood is sealed in the autoclave, vacuum is applied using a single-stage Nash vacuum pump. This removes some surface moisture and expands cell structure for easier penetration. Removal of air at this point accelerates, and makes more effective, the following stages of treatment. The length of the vacuum cycle varies with the type of wood. 
  • Filling - The preservative is introduced from a storage tank, initially by vacuum and finally by a multistage high-pressure solution transfer pump. 
  • Application of Pressure – Autoclave pressure is raised between 100 and 200 psig and held until desired penetration is achieved. The time required varies with the size and type of lumber, the solution pressure and the efficacy of the pre conditioning. 
  • Discharging the Solution – Any solution not absorbed by the wood is returned to the storage tank for reuse. In some cases, solution removal may be assisted by using compressed air.
  • Recovery Vacuum – Another round of vacuum is used to help the bonding of the active principles of wood. 
  • End of Cycle – The autoclave returns to atmospheric pressure and the wood is removed.

NASH liquid ring vacuum pumps offer the following features and benefits for wood treatment applications:

  • Ability to handle, process carryover or recycled gases - increases operating efficiency and reduces operating costs
  • Long design life – highest reliability
  • No internal lubrication required -  less maintenance and less downtime
  • No metal – to – metal contact – simple operation and wear-free performance
  • Cool running – incoming vapor is condensed and smaller, less costly equipment can service application
  • Only one moving part – simple and trouble-free operation
  • Proven energy-efficient design – lower operating costs
  • Over a century of engineering and application experience – peace of mind

Watch This Animation from Nash to Learn How Our Liquid Ring Vacuum Pumps Work In Wood Treatment Applications

Best solution for Vacuum Pressure

The Vectra XL vacuum pump design includes improved cone angles, which decrease the size of the pump. The Vectra XL also utilizes NASH’s patented Gas Scavenging Technology, which improves pump performance at high vacuum levels.

Furthermore, VectraPaks are standardized pre-engineered solutions containing the necessary components that are assembled and piped. Customers purchase these because they arrive quickly and are ready to install.

The NASH SC is the most popular pump that delivers reliable performance with a broad range of suction volume, vacuum, and pressure. The SC series is a single-stage liquid ring vacuum pump available in 9 different models, with a capacity ranging from 130 to 3,200 ACFM (220 to 5,440 m3/hr).

Global Provider

NASH is a leading global provider of liquid ring vacuum pumps. For over 110 years, Nash has been providing reliable, engineered systems that stand up to the rigorous, nonstop demands of harsh industrial environments.

Downloads For Vacuum Pressure Impregnation For Wood Treatment

NASH Liquid Ring Pumps, Compressors & Systems - Vectra XL Series

Vectra XL Series