Paper Mill Open Air Cushion Hydraulic Headbox for Paper Pulp Making Machine

Product Description

Headbox for Paper Machine

As the core front-end equipment of the paper machine dewatering element system, the headbox is known as the "heart of the paper machine". It is a key hub connecting slurry flow, sheet formation and dewatering processes, directly determining paper sheet uniformity, strength and basis weight stability, and further affecting the dewatering efficiency and service life of subsequent dewatering elements. This headbox covers three mainstream types: open type, air cushion type and hydraulic type, which can be selected according to the paper mill's production capacity, paper type requirements (cultural paper, packaging paper, tissue paper, specialty paper) and dewatering process. Adopting precise hydraulic design and corrosion-resistant materials, it can spray the diluted pulp suspension onto the forming fabric along the full width of the paper machine at a uniform and stable flow rate and angle, effectively dispersing fibers, preventing flocculation, coordinating the pulp-wire speed ratio, and laying a solid foundation for the efficient work of subsequent dewatering elements. It meets the needs of medium and high-speed operation, helping paper mills improve production efficiency and reduce energy consumption and production costs.

Specification

Product Classification

According to the structure and working principle, the headbox is mainly divided into three types: open type, air cushion type and hydraulic type. The three types of products are suitable for different papermaking processes, dewatering requirements and paper types. The core differences focus on pressure control, injection stability and adaptive vehicle speed, as follows:

1. Open Type Headbox

The open type headbox is a basic headbox with simple structure and economical cost. It has no closed pressure chamber, and the slurry is transported and sprayed to the forming fabric by its own gravity and slight liquid level difference, belonging to the atmospheric pressure headbox. Its core advantages are simple structure, easy manufacturing, easy cleaning and maintenance, low failure rate, suitable for low-speed paper machines (speed ≤ 300m/min), mainly used for the production of medium and low-grade paper such as tissue paper and ordinary packaging paper, and can be used with basic dewatering elements. This type of headbox has moderate slurry distribution accuracy, and the fiber dispersion effect meets the basic production needs. The material is 304 stainless steel, corrosion-resistant and not easy to hang pulp, suitable for small and medium-sized paper mills and old production line transformation. Its core function is to complete the preliminary distribution of slurry and provide a basic paper sheet for the subsequent dewatering process.

2.Air Cushion Type Headbox

The air cushion type headbox forms a stable air cushion in the box and uses air pressure to control the slurry pressure to achieve uniform injection. It is a mid-range product between open type and hydraulic type. Its core characteristics are stable pressure and better injection uniformity than open type, suitable for medium-speed paper machines, widely used for the production of medium-grade paper such as cultural paper and carton board, and compatible with various conventional dewatering elements. This type of headbox is equipped with an independent air pressure stabilization system, which can flexibly adjust the air pressure to control the jet speed and reduce paper defects such as streaks and uneven basis weight; the internal segmented slurry distribution design improves the cross-width slurry distribution accuracy. The material is 316L stainless steel, corrosion-resistant and wear-resistant, which can adapt to the pulp white water environment for a long time. It also has the advantages of easy maintenance and moderate energy consumption, balancing production efficiency and cost control.

3. Hydraulic Type Headbox

The hydraulic type headbox is currently a high-end and efficient mainstream type. It relies on hydraulic pressure to control slurry flow and injection, without an air cushion structure. Through precise hydraulic design , it achieves efficient dispersion and uniform distribution of slurry, suitable for high-speed paper machines, mainly used for the production of high-grade cultural paper, specialty paper and other products with high requirements for paper quality, and can be used with high-performance dewatering elements. Its core advantages are high slurry distribution accuracy and stable injection, which can effectively disperse fibers, prevent flocculation, and significantly improve paper uniformity and surface quality; it is equipped with a precise pressure regulation system, which can achieve perfect matching between pulp speed and wire speed, reduce paper breaks, and reduce the wear of subsequent dewatering elements; the material is 316L stainless steel, precision processed, with surface roughness ≤ 0.2um, strong sealing, not easy to hang pulp, easy to clean, and strong long-term operation stability, helping paper mills achieve high-speed, efficient and high-quality production and reduce comprehensive production costs.

Core Structure

Whether it is an open type, air cushion type or hydraulic type headbox, it is composed of three core parts: slurry distribution device, rectification device and wire feeding device. All components work together to complete the whole process of slurry transportation, homogenization and injection, providing guarantee for the efficient work of subsequent dewatering elements. With precise structural design, strong sealing, easy cleaning and maintenance, it meets the high-efficiency operation needs of modern papermaking equipment.

1. Pulp Supply Device 
The pulp distribution device is the core component for feeding and uniform distribution in the headbox, primarily responsible for evenly, stably, and disturbance-free allocation of pulp from the supply system along the width direction of the paper machine. It ensures consistent pulp flow and concentration across the entire width, eliminating uneven lateral distribution issues at the source. Through optimized flow channel design and pressure balance mechanisms, this component prevents vortex formation, flow deviation, or localized accumulation of pulp, laying a uniform foundation for subsequent rectification processes. It serves as a critical link in ensuring uniform grammage across the paper web.
2. Rectification Device 
The flow straightening device is the core of the headbox's flow stabilization and homogenization, receiving the pulp delivered by the distribution device. Its primary functions are to eliminate turbulence, stabilize pulp flow velocity, and enhance fiber dispersion. Through the regulating effect of flow straightening elements, the pulp flow velocity is made uniform, ensuring thorough fiber dispersion without directional alignment. Simultaneously, it removes bubbles and stress from the pulp, allowing the pulp to enter the next stage in a stable and homogeneous state. This directly determines the uniformity, fiber orientation, and surface quality of the final paper product.
3. Webbing Device 
The web forming device serves as the core for discharging and forming in the headbox, located at the end of the headbox. Its primary function is to spray the homogenized pulp onto the papermaking wire at precise, stable speed and angle. By controlling the lip opening, spraying speed, and deposition point, it ensures uniform pulp distribution on the wire cloth, achieving smooth connection between the pulp and the wire section. This minimizes issues such as flocculation and holes caused by spraying impact, ultimately providing an even pulp layer for paper formation and ensuring consistent thickness and density of the finished paper.

Core Performance Advantages

All three types of headboxes adopt scientific slurry distribution design, achieving different precision of cross-width slurry distribution according to different types, with hydraulic type being the best, air cushion type next, and open type meeting basic needs. It effectively reduces paper defects such as streaks and pinholes, provides guarantee for uniform dewatering of subsequent dewatering elements, and improves dewatering efficiency.

Adaptable to Different Working Conditions

Durable and Easy to Maintain

Different Type Advantages

The open type is suitable for low-speed, medium and low-grade paper types and basic dewatering processes; the air cushion type is suitable for medium-speed, medium-grade paper types and conventional dewatering elements; the hydraulic type is suitable for high-speed, high-grade paper types and high-performance dewatering elements. It can be flexibly selected according to the paper mill's production capacity, paper type and vehicle speed, balancing practicality and economy.

All adopt stainless steel materials, corrosion-resistant and wear-resistant, suitable for pulp white water environment, not easy to hang pulp and easy to clean; the structure design is simple, the failure rate is low, daily maintenance does not require complex processes, which can extend the service life of the equipment, reduce the wear of subsequent dewatering elements, and reduce the cost of shutdown maintenance.

Open type has high cost performance and is suitable for old production lines; air cushion type has stable pressure and moderate energy consumption, balancing accuracy and cost; hydraulic type has high accuracy and stable injection, suitable for high-speed and high-yield production, helping to improve paper quality and production efficiency.

Technical Specifications

Parameter	Open Type	Air Cushion Type	Hydraulic Type
Applicable Speed	≤300m/min	300-800m/min	≥800m/min
Cross-width Basis Weight Deviation	≤±2.0%	≤±1.5%	≤±1.0%
Material	304 Stainless Steel	316L Stainless Steel	316L Stainless Steel
Pressure Control	Liquid Level Gravity	Air Cushion Pressure	Hydraulic Pressure
Applicable Paper Type	Tissue Paper, Ordinary Packaging Paper	Cultural Paper, Carton Board	High-grade Cultural Paper, Specialty Paper
Matching Dewatering Elements	Basic Forming Board, Common Suction Box	Ordinary Dewatering Elements, Low Vacuum Suction Box	High-performance Dewatering Elements, High Vacuum Suction Box

After Sales Service

Quality Assurance

·All headboxes have undergone strict raw material testing, dimensional accuracy testing, pressure testing and trial operation testing to ensure stable equipment operation;

·The material meets the corrosion resistance and wear resistance standards of the papermaking industry, and the slurry distribution accuracy and injection stability meet the standards; 

·12-month warranty period is provided, and a professional technical team provides installation guidance, commissioning and after-sales maintenance services. 

·Products can be customized according to customer drawings, paper machine parameters and dewatering requirements to ensure perfect adaptation of the equipment with dewatering elements and papermaking production lines.