Factors That Impact A Bulk Solid’s Flowability

When handling bulk solids, there are several factors that can affect your material flow. Most of these are environmental; all of them need to be taken into consideration. Moisture content, temperature, particle size, and time of storage at rest can have a tremendous impact on your material’s flow properties. How your material flows is a function of its cohesive and friction properties. As such, conditions that affect the cohesive strength and friction properties will have an impact on its handling capabilities. In the following article we will examine each factor.

Moisture Content
In my career as a solids handling consultant, I have observed that “as the moisture content of a solid increases, so does it’s cohesive strength.” However, there is a point at which some solids become saturated and behave more like slurries than solids. Even though there may be only a slight increase in moisture – say from 5-6% – the flowability of your material can be significantly impacted. Hygroscopic materials can experience significant moisture increases simply by being exposed to humid air. Your material flow properties should be measured using a representative value for moisture content.

When you are having your material flow properties evaluated, make sure that the testing laboratory determines the moisture content as you do, when they receive the sample, to ensure that they are working with representative moistures.

Cohesiveness is also affected by the solid’s temperature. Some materials are sensitive to increases in temperature (e.g. room temperature to 150°F). Others are sensitive to constant temperature. Perhaps you dry your product and deposit it into a storage silo and then allow it to cool. These conditions can be simulated in the laboratory through flow properties tests.
Soybean meal, for example, when stored in a bin or hopper at 90°F, is relatively easy to handle. At 110°F and greater, soybean meal becomes extremely difficult to handle and capable of bridging over very large openings. Additionally, when storing your product in cold weather and filling the storage silo with warmer product can cause moisture to migrate to the silo walls. For instance, if your warm material enters the silo at say 5% moisture, the moisture at the walls can increase to 8% easily. Obviously, this may affect your material flow.

Particle Size
I have also observed “as a bulk solid becomes finer, it also becomes more cohesive and subsequently more difficult to handle.” Fibrous and angular particles are usually more cohesive than particles that are rounded. Particles that are consistently ½ in. and larger do not typically present cohesive arching problems. They can, however, form interlocking arches. You cannot determine your material’s flowability from its particle size distribution.

Time of Storage at Rest

As a solid remains at rest in a bin or hopper, it can become more cohesive and difficult flowing. At rest, the compaction loads due to head pressure can produce a strong cohesive bond. A chemical reaction, crystallization, or adhesive bonding can also cause this. Sometimes, after a cohesive arch is broken up, say by somehow initiating flow (likely with a sledge hammer), the material can revert back to its original flow condition and not exhibit a similar cohesion if left at rest again. More often than not though, materials will bridge and rathole after remaining a rest for some period, even after flow is re-initiated.
This is why it is absolutely necessary to measure the flow properties of your material to determine the affects of the environmental conditions discussed above.

7 Proven Ways to Genuinely Connect With Your Employees

Communicating openly with your employees, recognizing them for good work, and giving them room to grow will vastly improve their engagement and your company’s bottom line.

What kind of difference would it make for your company to get every one of your employees excited about solving problems, making recommendations, expressing their new ideas, and taking care of your customers?

Every company today needs employees who are enthusiastic and who bring the very best of themselves to work. Companies need this not just from top performers but from every employee, every day, in order just to be competitive and survive, let alone thrive. The single element that distinguishes one company from another more than anything else is its people and the effort they exert.

The secret to unlocking this unlimited source of energy for your company is to build and strengthen the bonds between you and your employees. When you trust and respect your people–and really connect with them–they will respond with commitment and enthusiasm.

Give these seven strategies for connecting with your employees a try and see for yourself how your organization will benefit.

1. Put people first.

All employees–no matter what their positions are or how well they perform their jobs–want to be respected and valued for their contributions. Respect comes in many different forms: respecting opinions, respecting time, respecting culture, and more. And respect is a two-way street. Employees also need to respect their employers and their own careers instead of viewing their jobs and salaries only as entitlements.

2. Create a safe haven.

In many organizations, bosses rule their employees through bullying, threats, and intimidation. Unfortunately, over the long term, fear causes employees to contribute less to their organizations and to disconnect both mentally (checking out, clamming up) and physically (absenteeism, resignation). Employees must feel safe when they take the initiative to try something new, whether or not the idea works. It’s your job to provide your people with a safe haven to bring forward their ideas, and to tell the truth–no matter how hard it may be for you to hear.

3. Break down barriers to information.

Information is power, and bosses have traditionally wielded this power by selectively granting information to employees or withholding it from them. Organizations today can no longer afford the practice of selective communication. Employees must be informed–through constant, complete, and unfettered communication by their co-workers, managers, and customers–about what’s going on in the organization and their place within it. Only when they have complete information can they and will they give all they have to their organization.

4. Create golden opportunities for personal growth.

Owners have an inherent interest in ensuring that their organizations get the biggest bang for their buck, that is, that revenue is maximized, expenses are minimized, and customers are consistently delighted with the products and services they receive. The granting of stock and other financial incentives is one way to develop a sense of ownership in employees. But there are many other nonfinancial ways that leaders can instill an owner’s mentality in the workplace, including giving employees real responsibility and authority to make decisions that affect their jobs and their work.

5. Undo the organization.

In the past, rigid, bureaucratic, and rule-bound organizations were the model of consistency, dependable results, and steady if not stellar profits. However, this old model of business is now officially extinct, and a new model of business–a lean model built on speed, flexibility, and the active involvement of frontline employees–has taken hold. When you give your employees the responsibility and the authority to do their jobs, you and your organization will be successful because you’re depending on them to do the right thing on their own instead of depending on policies and procedures that force them to do so.

6. Engage your people.

Although many organizations have spent a lot of time over the past few years developing and installing elaborate employee suggestion systems, few have made them a permanent part of the way they do business. Even fewer actually implement the good suggestions they receive. This is a mistake. Employees are a tremendous potential source of organizational improvement, and you should make it a point to regularly tap this wealth of ideas.

7. Make recognition a way of life.

Despite years of research proving the overwhelmingly positive effect of employee recognition on the bottom line, few bosses take the time to recognize and reward their employees for a job well done–and even fewer employees report that they receive either recognition or rewards at work. The amazing thing about this is that the most effective forms of employee recognition cost little or no money, such as verbal and written thank-you’s for employees who do a good job, and publicly celebrating team and group successes.