The Velan Challenge

The Challenge - The United States Navy

In the early 1950s the United States Navy approached Velan Engineering with a challenge.  The Navy wanted a new steam trap designed to do the following things:

  1. Work on high pressure – high temperature applications.
  2. Waste no steam.
  3. Operate quietly with no blast discharge.
  4. Last longer than anything else in the marketplace.

 

The Navy also had two other conditions:

  1. All valve seats must be stellite #6.
  2. Be unaffected by waterhammer.

 

This was the challenge.  Velan Engineering created a product for the United States Navy that has been unmatched in durability, reliability and efficiency to this day.

The Challenge - The Velan Idea

 

Due to the fact that the current product offerings in the marketplace in 1947 did not handle high pressure – high temperature application well, Velan Engineering had to think outside the box as far as steam trapping. All manufacturers of the day discharged condensate at steam temperature. Velan looked at drip leg applications and asked, “What advantage is there in discharging condensate at saturated temperature?”  “If I lowered the temperature of the condensate a determined amount,” Velan surmised, “wouldn’t less flash steam be created in the condensate return system, and wouldn’t less turbulence occur across the seating surface?”  This was the beginning of the Velan theory of steam trapping for the marketplace.

DISCHARGE AT NEAR-TO-STEAM TEMPERATURES

The standard Velan steam trap opens only when condensate temperature drops 15-20ºF below saturated temperature.  During this time the comparatively small quantity of near-to-steam temperature condensate collects in the drip pockets. Standard drip pockets, following established good piping practice, is all that is required to keep equipment free of condensate and eliminate steam leakage.

 

ADVANTAGE

The drop in temperature of the accumulating water causes a slight drop in pressure. Water particles flowing with steam can easily find their way into the drip pocket. Because the trap is under water most of the time, leakage of steam is impossible. Trap remains tight in presence of superheat.

The Challenge - Applications at a Glance

When Velan Engineering looked at steam trapping in the marketplace, they noticed that many different manufacturers were selling the same designs.  They tried to sell their products with a universality of applications, meaning that one trap fit all.  Velan looked at this and said that this is not true.  There are really two applications in all steam systems, and each has an inherently different function.

 

 

  1. There are drip leg/Tracing applications.
  2. There are heating/process applications.

 

Velan figured that each application had a different set of pro's and con's.

The Challenge - Drip Legs/Tracing


When A.K. Velan looked at drip leg and tracing applications, he realized that they both shared similar characteristics. Steam traps on those two applications had to:

  1. Handle a controlled startup load.
  2. Handle low to medium flow conditions.
  3. Discharge large quantities of air.

 

The available steam traps in the marketplace at that time only discharged condensate at steam temperature.  Velan looked at the population of drip leg / tracing applications and realized they constituted the majority of all steam traps in a plant.  Therefore, Velan reasoned, what advantage was there to the customer to discharge condensate at steam temperature on these applications when discharging it a few degrees below saturated temperature would yield the following advantages:

  1. Steam traps that constantly modulate condensate at all times will create a pressure drop in the drip leg or tracing line and precipitate better condensate drainage, versus blasting open, then clearing whatever had formed in the drip pot.
  2. Steam traps that modulate versus blast on – blast off will last longer.
  3. Steam traps that discharge condensate a few degrees below saturated steam temperature will help lower condensate return pressures, thus putting less stress on the other steam traps and the condensate pumps.

The Challenge - Applications at a Glance
Forced Heat Applications


When A.K. Velan looked at forced heat applications, he realized that those applications had different requirements than drip leg and tracing applications.  Steam traps on heat transfer applications had to:

  1. Handle a large startup loads.
  2. Handle varying flow conditions.
  3. Discharge large quantities of air.
  4. Get rid of condensate at steam temperature.

 

The available steam traps in the marketplace at that time did a very good job of discharging condensate at steam temperature.  A.K. Velan saw the need for a mechanical steam trap, but realized that under low flow conditions, a thermostatic steam trap would still give great advantage to a steam trap’s longevity.  Therefore, Velan reasoned, what advantage was for the market if he created a thermostatic steam trap that acted like a mechanical steam trap if the flow forced the trap to behave that way.

  1. Steam traps that constantly modulate condensate at all times will create a pressure drop in the forced heat application and precipitate better condensate drainage.
  2. Steam traps that modulate versus blast on – blast off will last longer.
  3. Steam traps that discharge condensate a few degrees below saturated steam temperature will help lower condensate return pressures, thus putting less stress on the other steam traps and the condensate pumps.

Steam traps that can open mechanically and override the thermostatic bimetallic element, can be manufactured with only one orifice.  Therefore, the trap can only fail in the open position.  The steam trap WILL NOT FREEZE, if placed in a climate below 32 deg F.