Plant Maintenance

Road Tanker Compartment Design

Road Tanker Design For Fast Unloading And Onshore Pump Drain Tank. To completely empty a road tanker the compartments need to be designed to have a sump that permits total drain-out of the liquid from the lowest point. If a pump is mounted on the trailer, it is best mounted under the trailer. Where a pump is mounted on the tray or fenders it will cavitate at low tanker liquid levels. For an onshore unloading pump installation it is best to install a buffer tank between the tanker and onshore pump to let the road tanker completely drain-out before the pump starts cavitating. Tanker load-out pumps must have a very low net positive suction head requirement.

Using Reliability Principles for a Cheap Way To High Pumping Circuit Availability. High plant availability is achieved by having redundant equipment that can be brought on-line as soon as the operating unit has failed. Redundancy is expensive as there are two items to buy, two to install and two to maintain at full operating capacity. There is an alternate option for maintaining high pumping circuit availability by designing quick methods to bring mobile equipment into the circuit when pumps are down. This article explains how to set-up piping for a mobile pump to maintain operation when the normal duty pump is out of use.

Use an Isocorrosion Diagrams To Recognise High Corrosion Situations And Design Process Equipment Accordingly. A true story of how a high nickel alloy (Alloy 28) reactor was holed in 8 weeks by sulphuric (sulfuric) acid running down the inside wall. When the situation was reviewed in detail using an iso-corrosion diagram for the alloy in sulphuric acid it was obvious that such a problem would occur. The iso-corrosion curves clearly showed the huge corrosion rates that would happen at local contact points within the reactor. A clear and detailed understanding of how to use iso-corrosion curves would have highlighted the problem at the design stage.

Mother Nature And Father Time have together built well. What they have left behind lasts a long time without failure. Humans can run for 100 years with very little maintenance. Trees can run for thousands of years without maintenance. There are lessons for us to take and apply. The life on our world shows us how to achieve truly outstanding reliability and availability. Do you want a thing to last 20 years trouble-free all its life, maybe 50 years without a problem? By looking at what the Mother Nature And Father Time left behind you will find the answers.

Error Proof Quick Mating Part Location And Alignment. For speedy and easy maintenance it is best to design equipment with a means to insure accurate and exact location of contacting parts. This removes the opportunity for alignment errors during rebuilds and speeds-up maintenance overhauls. In this article is a sketch of two common methods used to provide positive and certain location and alignment between mating parts.

Split And Clamped Mounting Hub For Shaft Attachments. For speedy and easy maintenance it is best to use a clamped hub to mount attachments to shafts when possible. This article presents a conceptual design of a split hub bolted and clamped to a shaft. The required attachment is then mounted to the removable hub.

Pressure Flange Seal For Liquid Filter Pressure Vessel. When a leak occurs between pressure flanges and the arrangement cannot be successfully sealed, it is necessary to change the sealing design. This article explains a successful modification done to the lid and body flanges of a vertical pressure leaf filter used to remove particulate from a liquid stream. It incorporates a ‘tongue and groove’ sealing arrangement, with the ‘tongue’ in the lid flange and the recess in the filter body flange.

Dust ingress into bearings is one of the great causes of premature bearing failure on bucket elevators. By selecting the right bearing housing and position, combined with this special dust seal arrangement, you can get quadruple the bearing life. The article provides the full details of the low pressure dust leak seal design along with a sketch of the successful set-up.

There is always a degree of uncertainty in selecting instrumentation for difficult or corrosive environments. Material selection for chemical compatibility involves a strained decision between cost and equipment reliability and longevity. The other major uncertainty is whether the instrument is appropriate for the application – will it repeatedly give truly representative readings all it’s operating life? This article presents a list of instrumentation successfully used in a range of difficult and chemically demanding environments.

The cyclo-drive gearbox is a variation of a planetary gearbox. They have the added advantage of not using gear teeth to drive the shafts; rather they use an internal offset cam arrangement to drive rolling pins that turn a cycloidal wheel inside the gearbox. The rollers are capable of taking 500% overload without breaking the gearbox. One other benefit of the cyclo-drive gearbox for users is that many models are grease filled and do not use oil.

Acid Sparge And Acid Sparging. When you want to introduce acid directly into a liquid below its surface a sparge pipe is used. It is necessary to select materials that are compatible with the chemicals and the process. This article explains the issues to address when selecting the sparge pipe materials for injecting acid into a process reactor and what to consider when designing and installing the sparge pipe into such vessels or tanks.

Air Mover And Air Amplifier problems! Touted as great maintenance savers and a very efficient means of moving large volumes of air, they can in fact be extremely energy hungry. Based on using a small amount of compressed air to draw through a large amount of entrained air they can cause huge energy waste if an air compressor is run in order for the air mover to operate. It is wasteful to install an air mover on a plant air system unless the air compressor is always running well under peak demand.

Budgets represent plans or expectations for the future! They are a means to plan, forecast, coordinate and control the activities needed to achieve the business’ objectives. The budget document contains the amount of money that has been allocated to achieve those goals and the timing of its spending. Budgets cover the planned use of men, materials, external resources and management effort that is expected to be sufficient to hit the targets. Once the budget is finalised it becomes a tool to feedback how the actual progress is going compared to what was expected. [Read more…]

Tracking belts on bucket elevators and short belt conveyors. Flexible, flat belts are used on bucket elevators and belt conveyors to carry loose, bulk product. The belt is stretched tight from head drum to tail drum and the friction generated on the turning head drum is used to drive the belt and carry the product. The belt must run true on the end pulleys (drums) and stay within the sides of the equipment structure. If the belt runs off the drums, buckets will be destroyed and belt edges frayed. In the worst cases the belt runs off the pulleys resulting in a breakdown repair. Proper and long- lived tracking of belts is critical for trouble-free operation. [Read more…]

Bag house dust bag selection. The dust bags within a bag house must handle the process conditions they experience. The choice of bag materials is usually based on the cheapest fabric that will handle the conditions for a minimum of 3 to 5 years’ operation. The selection of the bag materials requires a good understanding of the process temperature, moisture content, chemical reactions with the bag fibre, dust loading effects and behaviour of the dust bags in operation. [Read more…]