HVAC Duct Valve Application

Application Description

An HVAC 6' × 6' duct valve is located 30 feet above a manufacturing process facility floor. The baffle needs to be adjusted periodically to maintain proper airflow through the building. The loads, duty cycle and other operation details have been identified. The concern is with the amount of dust and particulate that will accumulate on the actuator due to the fact that it is located directly above foam manufacturing equipment. Electric cylinder systems from Nook Industries are the solution.

Step 1: Determine Specifications

  • Maximum force to open and close the valve under maximum airflow is 2,000lbs
  • Cylinder will be in compression
  • Maximum speed is 32 inches per minute
  • Actuation cycle: 2 times per day; 365 days per year
  • Desired design life is twenty years
  • Mechanism must be mounted overhead
  • Limit Switches needed
  • Maximum stroke is 18 inches

Step 2: Analysis

There is a specific life requirement so the type of linear motion system required is a ball screw actuator. As shown on the Series DD-25 product reference page 366 of our Precision Screw Assemblies Catalog, using the DD-2512-HD with a 1/2 hp brake motor will provide a travel rate of 36"/min and give 4.1 million inches of life at 2,000 lbs.

Additionally, the charts show that this application is within the column load strength of the DD-2512-HD. The door swings through an arc so a double clevis style will be needed. Due to the environment concerns an enclosed Rotary Limit Switch should be used instead of a Rod type Limit Switch.

Step 3: Product Selection

DD-2512-HD / 05BT -1 / 2CA - 4E / CC / 18 / S Figure 1


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