Poppy and the Steam Forum and Power Forum

Welcome to the steam and power forum, a bulletin board dedicated to questions and answers to Steam Plants and Power Generation Plants for steam boilers, turbine generator and heating problems. Dedicated to power plants, power generation, supercritical, and heating plants as well as steam boilers, steam turbine generators, gas turbines or combustion turbines, hrsg, steam heating, pressure vessels, steam line, including ASME questions and more. Remember the forum is made up of volunteers from experts to beginners. Unfortunately, we cannot allow free commercialism that promotes products, services, or sites.
 
The Steam Forum and Power Forum is being sponsored by the following:
Poppy   Steam Forum  

Lou Okonski on Non return valves sticking

By: Lou Okonski [1187] 1 Stars
Date: Wednesday, January 19, 2011
Time: 8:08:43 AM

Than you much for the attention to my post. The 6 right angle non return sits on the top of the steam outlet which sits on top of the steam drum of a 20,000#/hr CE boiler. The steam will leave the boiler vertically and turn 90 degree through the valve. Down stream there is a gate isolation valve. The line then travels from the isolation valve into the main steam header for distribution. This setup is identical on the four boilers. Importantly, the non return protects personel and property by closing in the event of a tube failure or the like and not allowing steam to discharge through the plant. As many of you know, a non return is a code requirement in a multi boiler system going into a common header.

Another function the non return supplies is to bring the boiler on line by allowing the disc in the valve to slide open when the valve disc sees enough force to lift. The pressure differential needed to lift the disc is calculated by the weight of the disc and the surface area of the disc with a little friction small amount thrown in. This I understand is 1/2 psi to 2psi or therabouts. There may be a little chatter as the valve seat lifts.

When buying an NRV, it becomes important to size the NRV to the steam flow of the boiler not necessarily to the outlet size. In most plants that we are in the NRV is sized to match the outlet. That means that many NRVs in the world are oversized. Obviously the outlet has been designed to allow for maximum steam that the boiler can supply or more. What this says to me is that we cannot simply look at the valve and replace in kind. It also beggers a question Has something changed and what?. When replacing a NRV with a smaller one, a code spool piece would have to be made on both sides of the valve. This complicates matters in a retrofit because of the dimensional change. Oh that we could just change like for like. This is an area of the steam plant that is overlooked.

Again, has something changed such as the design of the NRVs or is this something that valve manufacturers are doing due diligence on after years of just selling. I have heard from the people that both sell and rebuild valves that there is a difference between older valves and the newer imports. I myself have more confidense in an old rebuilt because of being bit hard in this situation. With four valves from the same manufacturer, bought at the same time, slamming at 30-40 psi differential something is wrong.

The leak by on old valves most likely comes from a worn seat. The seat wear can be from erossion or seat chatter. These are easily machined and often at 1/4-1/3rd the cost of a newer valve 6 and up. We have gotten numerous valves rebuilt with success. There were a few that were too far gone.

Mostly, I wanted to share my experience with the message that NRVs are not as simple as may first be seen. Also wanted to get feedback from this respected forum.
Thank you
Lou

Click on picture for full size view or to view PDF!


Viewed 1025 times
Published on steamforum.com

 

 


There are three-methods to find all the replies to this steam or power forum question or answer: 1) Use the 'Next >>' or '<< Previous' menu links above, or 2) Look at the year of the post and click on the applicable year an scan the postings for the date/title, or 3) Use the 'View Post Tree' feature, which is new to help you find all tree-truncations to the postings and replies on the steam & power forum that you are interested in.

Featured
High Sulfite Residual
By: Ross. [390]

First, I want to say that large amounts of Sodium Sulfite NaSO3 becomes a contaminate because it will produce foaming and other problems, but foaming is the primary problem.

Your 500-psi Water Tube Boiler is seems to have reasonable level of residual Sodium Sulfite NaSO3 remaining in the boiler water. Nice pH too.

Your 300-psi Waste Heat Recovery Boiler has twice what I would expect for Sodium Sulfite NaSO3 at ranging 80-ppm to 100-ppm. pH is good so you are getting a good yield.

As....   Read All
Advertising Info - Click Here!

It's hard not to look at this ad at least once, then you go to the next page an notice it again. Maybe you will not read the message, but you will be thinking about the brand and we call that brand impressions.

About 2/3 of internet traffic is useless traffic and consist mostly of malicous-bad-robots.  However, there are good robots too.  We block bad-robots, and allow the good one's through, but we just do not count the good one's.  We want good straight-brand impressions for our advertisers with human impressions!

Imagine your static or animated display advertisement placed here, and if that is not enough you can include text too to expound on the virtues of your services and or products.    In addition, you can benefit by using our new advertisement feature to have your video included in your ad space.  Wow, make an infomerical with text and a display by combining all features to enhance the readers or audience's experience using your brand.  Ads can be much more than a static display ad. Here is an example of how your video could be used or position in this ad space:

 

Caption: This public domain video shows from TGM - Turbine Generator Maintenance - who provides the Right Plans, Processes, People, Tools and Attitude to provide superior Turbine Generator inspection and repair.  The author of the video is not an advertiser and is being used to show how the video ad can be of value to the reader since you have already being viewing the video.  It is hard not to think about the authors brand after viewing the video ad.  This is the benefit of Branding.

- Ask for our Media Kit -

 

 

A Long-Game that Earns Tomorrow's Sales


Click on this Promotional Advertisement to Contact Us Today!

Good Branding Puts Your Brand or Company in the Front of a Decision-Maker’s Mind for a Purchase either Months from Now or Five-Years in the Future.

Good branding makes your brand or company the leader in a crowded field of other brands or companies vying for your potential or existing client's attention. 

An invitation to the buyer's table to negotiate potential sales from $thousands to $millions of dollars in any of these: Systems sale, Capital Equipment, Upgrades & Modifications,  Repairs, or Capital Project becomes easier now with a recognized brand that thinks forward by brand advertising.

Your advertising will cost you an unbelievable low amount, so ask for our Media Kit that has Specs and Rates. 

Below is some of our demographic data for steam and power forum users will speak for itself:

Bus Sector Percent   Education Percent
Manufacturing 11%   College 51%
Power Gen 20%   Grad School 20%
Chemical & Petroleum 15%      
Medical Facilities 6%      
Pulp & Paper / Forest 7%      
Pharmaceutical 7%      

Our network works hard for you with placements for full coverage on part of the network, or full network placement.  Brand yourself today and don’t miss-out on being invited to your client or future client's table because they forgot you.  Be the leader they will remember and be part of their capital project.  Tomorrow’s clients are your future.

 

Advertising and Marketing Agency for the steam and power forum
PE Marketing, LLC

Branding.jpg

Sponsors/Advertisers
Industrial Training School
 
Industrial Training School - Maintenance
 
Industrial Training School
 
National Assoc of Stationary Operating Engineers
 
Confidentiality, Disclaimer; Policy
STEAM and POWER FORUM
© 2001 to Steam Forum, All Rights Reserved.
PE Marketing LLC is representing the steamforum for advertising and marketing
Valid XHTML 1.0 Transitional